resources: Enhancements to user and group

This patch adds autoedges between users and groups, and extends
users with additional fields for supplementary groups and a named
primary group. Also, some small fixes to log and error messages.

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,9 @@
+## Versions:
+
+* mgmt version (eg: `mgmt --version`):
+
+* operating system/distribution (eg: `uname -a`):
+
+* golang version (eg: `go version`):
+
+## Description:

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,36 @@
+## Tips:
+
+* commit message titles must be in the form:
+```topic: Capitalized message with no trailing period```
+or:
+```topic, topic2: Capitalized message with no trailing period```
+
+* golang code must be formatted according to the standard, please run:
+```
+make gofmt		# formats the entire project correctly
+```
+or format a single golang file correctly:
+```
+gofmt -w yourcode.go
+```
+
+* please rebase your patch against current git master:
+```
+git checkout master
+git pull origin master
+git checkout your-feature
+git rebase master
+git push your-remote your-feature
+hub pull-request	# or submit with the github web ui
+```
+
+* after a patch review, please ping @purpleidea so we know to re-review:
+```
+# make changes based on reviews...
+git add -p		# add new changes
+git commit --amend	# combine with existing commit
+git push your-remote your-feature -f
+# now ping @purpleidea in the github PR since it doesn't notify us automatically
+```
+
+## Thanks for contributing to mgmt and welcome to the team!

.gitignore

@@ -2,6 +2,7 @@
 .omv/
 .ssh/
 .vagrant/
+.envrc
 old/
 tmp/
 *_stringer.go

.gitmodules

@@ -13,3 +13,12 @@
 [submodule "vendor/github.com/purpleidea/go-systemd"]
 	path = vendor/github.com/purpleidea/go-systemd
 	url = https://github.com/purpleidea/go-systemd
+[submodule "vendor/honnef.co/go/augeas"]
+	path = vendor/honnef.co/go/augeas
+	url = https://github.com/dominikh/go-augeas/
+[submodule "vendor/github.com/grpc-ecosystem/go-grpc-prometheus"]
+	path = vendor/github.com/grpc-ecosystem/go-grpc-prometheus
+	url = https://github.com/grpc-ecosystem/go-grpc-prometheus
+[submodule "vendor/github.com/ugorji/go"]
+	path = vendor/github.com/ugorji/go
+	url = https://github.com/ugorji/go

.travis.yml

@@ -1,18 +1,21 @@
 language: go
 go:
-  - 1.6
-  - 1.7
+  - 1.8.x
+  - 1.9.x
   - tip
+go_import_path: github.com/purpleidea/mgmt
 sudo: true
 dist: trusty
-before_install: 'git fetch --unshallow'
+before_install:
+  - sudo apt update
+  - git fetch --unshallow
 install: 'make deps'
 script: 'make test'
 matrix:
   fast_finish: true
   allow_failures:
     - go: tip
-    - go: 1.7
+    - go: 1.9.x
 notifications:
   irc:
     channels:
@@ -25,4 +28,7 @@ notifications:
     use_notice: false
     skip_join: false
   email:
-    - travis-ci@shubin.ca
+    recipients:
+      - travis-ci@shubin.ca
+    on_failure: change
+    on_success: change

AUTHORS

@@ -4,5 +4,7 @@ If you appreciate the work of one of the contributors, thank them a beverage!
 For a more exhaustive list please run: git log --format='%aN' | sort -u
 This list is sorted alphabetically by first name.
 
+Felix Frank
 James Shubin
+Julien Pivotto
 Paul Morgan

COPYING

@@ -1,5 +1,5 @@
-                    GNU AFFERO GENERAL PUBLIC LICENSE
-                       Version 3, 19 November 2007
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
 
  Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
  Everyone is permitted to copy and distribute verbatim copies
@@ -7,15 +7,17 @@
 
                             Preamble
 
-  The GNU Affero General Public License is a free, copyleft license for
-software and other kinds of works, specifically designed to ensure
-cooperation with the community in the case of network server software.
+  The GNU General Public License is a free, copyleft license for
+software and other kinds of works.
 
   The licenses for most software and other practical works are designed
 to take away your freedom to share and change the works.  By contrast,
-our General Public Licenses are intended to guarantee your freedom to
+the GNU General Public License is intended to guarantee your freedom to
 share and change all versions of a program--to make sure it remains free
-software for all its users.
+software for all its users.  We, the Free Software Foundation, use the
+GNU General Public License for most of our software; it applies also to
+any other work released this way by its authors.  You can apply it to
+your programs, too.
 
   When we speak of free software, we are referring to freedom, not
 price.  Our General Public Licenses are designed to make sure that you
@@ -24,34 +26,44 @@ them if you wish), that you receive source code or can get it if you
 want it, that you can change the software or use pieces of it in new
 free programs, and that you know you can do these things.
 
-  Developers that use our General Public Licenses protect your rights
-with two steps: (1) assert copyright on the software, and (2) offer
-you this License which gives you legal permission to copy, distribute
-and/or modify the software.
+  To protect your rights, we need to prevent others from denying you
+these rights or asking you to surrender the rights.  Therefore, you have
+certain responsibilities if you distribute copies of the software, or if
+you modify it: responsibilities to respect the freedom of others.
 
-  A secondary benefit of defending all users' freedom is that
-improvements made in alternate versions of the program, if they
-receive widespread use, become available for other developers to
-incorporate.  Many developers of free software are heartened and
-encouraged by the resulting cooperation.  However, in the case of
-software used on network servers, this result may fail to come about.
-The GNU General Public License permits making a modified version and
-letting the public access it on a server without ever releasing its
-source code to the public.
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must pass on to the recipients the same
+freedoms that you received.  You must make sure that they, too, receive
+or can get the source code.  And you must show them these terms so they
+know their rights.
 
-  The GNU Affero General Public License is designed specifically to
-ensure that, in such cases, the modified source code becomes available
-to the community.  It requires the operator of a network server to
-provide the source code of the modified version running there to the
-users of that server.  Therefore, public use of a modified version, on
-a publicly accessible server, gives the public access to the source
-code of the modified version.
+  Developers that use the GNU GPL protect your rights with two steps:
+(1) assert copyright on the software, and (2) offer you this License
+giving you legal permission to copy, distribute and/or modify it.
 
-  An older license, called the Affero General Public License and
-published by Affero, was designed to accomplish similar goals.  This is
-a different license, not a version of the Affero GPL, but Affero has
-released a new version of the Affero GPL which permits relicensing under
-this license.
+  For the developers' and authors' protection, the GPL clearly explains
+that there is no warranty for this free software.  For both users' and
+authors' sake, the GPL requires that modified versions be marked as
+changed, so that their problems will not be attributed erroneously to
+authors of previous versions.
+
+  Some devices are designed to deny users access to install or run
+modified versions of the software inside them, although the manufacturer
+can do so.  This is fundamentally incompatible with the aim of
+protecting users' freedom to change the software.  The systematic
+pattern of such abuse occurs in the area of products for individuals to
+use, which is precisely where it is most unacceptable.  Therefore, we
+have designed this version of the GPL to prohibit the practice for those
+products.  If such problems arise substantially in other domains, we
+stand ready to extend this provision to those domains in future versions
+of the GPL, as needed to protect the freedom of users.
+
+  Finally, every program is threatened constantly by software patents.
+States should not allow patents to restrict development and use of
+software on general-purpose computers, but in those that do, we wish to
+avoid the special danger that patents applied to a free program could
+make it effectively proprietary.  To prevent this, the GPL assures that
+patents cannot be used to render the program non-free.
 
   The precise terms and conditions for copying, distribution and
 modification follow.
@@ -60,7 +72,7 @@ modification follow.
 
   0. Definitions.
 
-  "This License" refers to version 3 of the GNU Affero General Public License.
+  "This License" refers to version 3 of the GNU General Public License.
 
   "Copyright" also means copyright-like laws that apply to other kinds of
 works, such as semiconductor masks.
@@ -537,45 +549,35 @@ to collect a royalty for further conveying from those to whom you convey
 the Program, the only way you could satisfy both those terms and this
 License would be to refrain entirely from conveying the Program.
 
-  13. Remote Network Interaction; Use with the GNU General Public License.
-
-  Notwithstanding any other provision of this License, if you modify the
-Program, your modified version must prominently offer all users
-interacting with it remotely through a computer network (if your version
-supports such interaction) an opportunity to receive the Corresponding
-Source of your version by providing access to the Corresponding Source
-from a network server at no charge, through some standard or customary
-means of facilitating copying of software.  This Corresponding Source
-shall include the Corresponding Source for any work covered by version 3
-of the GNU General Public License that is incorporated pursuant to the
-following paragraph.
+  13. Use with the GNU Affero General Public License.
 
   Notwithstanding any other provision of this License, you have
 permission to link or combine any covered work with a work licensed
-under version 3 of the GNU General Public License into a single
+under version 3 of the GNU Affero General Public License into a single
 combined work, and to convey the resulting work.  The terms of this
 License will continue to apply to the part which is the covered work,
-but the work with which it is combined will remain governed by version
-3 of the GNU General Public License.
+but the special requirements of the GNU Affero General Public License,
+section 13, concerning interaction through a network will apply to the
+combination as such.
 
   14. Revised Versions of this License.
 
   The Free Software Foundation may publish revised and/or new versions of
-the GNU Affero General Public License from time to time.  Such new versions
-will be similar in spirit to the present version, but may differ in detail to
+the GNU General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
 address new problems or concerns.
 
   Each version is given a distinguishing version number.  If the
-Program specifies that a certain numbered version of the GNU Affero General
+Program specifies that a certain numbered version of the GNU General
 Public License "or any later version" applies to it, you have the
 option of following the terms and conditions either of that numbered
 version or of any later version published by the Free Software
 Foundation.  If the Program does not specify a version number of the
-GNU Affero General Public License, you may choose any version ever published
+GNU General Public License, you may choose any version ever published
 by the Free Software Foundation.
 
   If the Program specifies that a proxy can decide which future
-versions of the GNU Affero General Public License can be used, that proxy's
+versions of the GNU General Public License can be used, that proxy's
 public statement of acceptance of a version permanently authorizes you
 to choose that version for the Program.
 
@@ -633,29 +635,40 @@ the "copyright" line and a pointer to where the full notice is found.
     Copyright (C) <year>  <name of author>
 
     This program is free software: you can redistribute it and/or modify
-    it under the terms of the GNU Affero General Public License as published by
+    it under the terms of the GNU General Public License as published by
     the Free Software Foundation, either version 3 of the License, or
     (at your option) any later version.
 
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Affero General Public License for more details.
+    GNU General Public License for more details.
 
-    You should have received a copy of the GNU Affero General Public License
+    You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 Also add information on how to contact you by electronic and paper mail.
 
-  If your software can interact with users remotely through a computer
-network, you should also make sure that it provides a way for users to
-get its source.  For example, if your program is a web application, its
-interface could display a "Source" link that leads users to an archive
-of the code.  There are many ways you could offer source, and different
-solutions will be better for different programs; see section 13 for the
-specific requirements.
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
 
   You should also get your employer (if you work as a programmer) or school,
 if any, to sign a "copyright disclaimer" for the program, if necessary.
-For more information on this, and how to apply and follow the GNU AGPL, see
+For more information on this, and how to apply and follow the GNU GPL, see
 <http://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<http://www.gnu.org/philosophy/why-not-lgpl.html>.

COPYRIGHT

@@ -1,16 +1,16 @@
 Mgmt
-Copyright (C) 2013-2016+ James Shubin and the project contributors
+Copyright (C) 2013-2017+ James Shubin and the project contributors
 Written by James Shubin <james@shubin.ca> and the project contributors
 
 This program is free software: you can redistribute it and/or modify
-it under the terms of the GNU Affero General Public License as published by
+it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU Affero General Public License for more details.
+GNU General Public License for more details.
 
-You should have received a copy of the GNU Affero General Public License
+You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.

Makefile

@@ -1,18 +1,18 @@
 # Mgmt
-# Copyright (C) 2013-2016+ James Shubin and the project contributors
+# Copyright (C) 2013-2017+ James Shubin and the project contributors
 # Written by James Shubin <james@shubin.ca> and the project contributors
 #
 # This program is free software: you can redistribute it and/or modify
-# it under the terms of the GNU Affero General Public License as published by
+# it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU Affero General Public License for more details.
+# GNU General Public License for more details.
 #
-# You should have received a copy of the GNU Affero General Public License
+# You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 SHELL = /usr/bin/env bash
@@ -37,6 +37,11 @@ RPM = rpmbuild/RPMS/$(PROGRAM)-$(VERSION)-$(RELEASE).$(ARCH).rpm
 USERNAME := $(shell cat ~/.config/copr 2>/dev/null | grep username | awk -F '=' '{print $$2}' | tr -d ' ')
 SERVER = 'dl.fedoraproject.org'
 REMOTE_PATH = 'pub/alt/$(USERNAME)/$(PROGRAM)'
+ifneq ($(GOTAGS),)
+    BUILD_FLAGS = -tags '$(GOTAGS)'
+endif
+
+default: build
 
 #
 #	art
@@ -105,9 +110,9 @@ $(PROGRAM): main.go
 	@echo "Building: $(PROGRAM), version: $(SVERSION)..."
 ifneq ($(OLDGOLANG),)
 	@# avoid equals sign in old golang versions eg in: -X foo=bar
-	time go build -ldflags "-X main.program $(PROGRAM) -X main.version $(SVERSION)" -o $(PROGRAM);
+	time go build -ldflags "-X main.program $(PROGRAM) -X main.version $(SVERSION)" -o $(PROGRAM) $(BUILD_FLAGS);
 else
-	time go build -ldflags "-X main.program=$(PROGRAM) -X main.version=$(SVERSION)" -o $(PROGRAM);
+	time go build -i -ldflags "-X main.program=$(PROGRAM) -X main.version=$(SVERSION)" -o $(PROGRAM) $(BUILD_FLAGS);
 endif
 
 $(PROGRAM).static: main.go
@@ -115,9 +120,9 @@ $(PROGRAM).static: main.go
 	go generate
 ifneq ($(OLDGOLANG),)
 	@# avoid equals sign in old golang versions eg in: -X foo=bar
-	go build -a -installsuffix cgo -tags netgo -ldflags '-extldflags "-static" -X main.program $(PROGRAM) -X main.version $(SVERSION)' -o $(PROGRAM).static;
+	go build -a -installsuffix cgo -tags netgo -ldflags '-extldflags "-static" -X main.program $(PROGRAM) -X main.version $(SVERSION)' -o $(PROGRAM).static $(BUILD_FLAGS);
 else
-	go build -a -installsuffix cgo -tags netgo -ldflags '-extldflags "-static" -X main.program=$(PROGRAM) -X main.version=$(SVERSION)' -o $(PROGRAM).static;
+	go build -a -installsuffix cgo -tags netgo -ldflags '-extldflags "-static" -X main.program=$(PROGRAM) -X main.version=$(SVERSION)' -o $(PROGRAM).static $(BUILD_FLAGS);
 endif
 
 clean:
@@ -183,7 +188,7 @@ $(SRPM): $(SPEC) $(SOURCE)
 #
 $(SPEC): rpmbuild/ spec.in
 	@echo Running templater...
-	#cat spec.in > $(SPEC)
+	cat spec.in > $(SPEC)
 	sed -e s/__PROGRAM__/$(PROGRAM)/g -e s/__VERSION__/$(VERSION)/g -e s/__RELEASE__/$(RELEASE)/g < spec.in > $(SPEC)
 	# append a changelog to the .spec file
 	git log --format="* %cd %aN <%aE>%n- (%h) %s%d%n" --date=local | sed -r 's/[0-9]+:[0-9]+:[0-9]+ //' >> $(SPEC)

README.md

@@ -2,18 +2,20 @@
 
 [![mgmt!](art/mgmt.png)](art/)
 
-[![Go Report Card](https://goreportcard.com/badge/github.com/purpleidea/mgmt)](https://goreportcard.com/report/github.com/purpleidea/mgmt)
-[![Build Status](https://secure.travis-ci.org/purpleidea/mgmt.png?branch=master)](http://travis-ci.org/purpleidea/mgmt)
-[![Documentation](https://img.shields.io/docs/markdown.png)](docs/documentation.md)
-[![GoDoc](https://godoc.org/github.com/purpleidea/mgmt?status.svg)](https://godoc.org/github.com/purpleidea/mgmt)
-[![IRC](https://img.shields.io/irc/%23mgmtconfig.png)](https://webchat.freenode.net/?channels=#mgmtconfig)
-[![Jenkins](https://img.shields.io/jenkins/status.png)](https://ci.centos.org/job/purpleidea-mgmt/)
-[![COPR](https://img.shields.io/copr/builds.png)](https://copr.fedoraproject.org/coprs/purpleidea/mgmt/)
-[![arch](https://img.shields.io/arch/aur.png)](https://aur.archlinux.org/packages/mgmt/)
+[![Go Report Card](https://goreportcard.com/badge/github.com/purpleidea/mgmt?style=flat-square)](https://goreportcard.com/report/github.com/purpleidea/mgmt)
+[![Build Status](https://img.shields.io/travis/purpleidea/mgmt/master.svg?style=flat-square)](http://travis-ci.org/purpleidea/mgmt)
+[![GoDoc](https://img.shields.io/badge/godoc-reference-5272B4.svg?style=flat-square)](https://godoc.org/github.com/purpleidea/mgmt)
+[![IRC](https://img.shields.io/badge/irc-%23mgmtconfig-brightgreen.svg?style=flat-square)](https://webchat.freenode.net/?channels=#mgmtconfig)
+[![Jenkins](https://img.shields.io/badge/jenkins-status-brightgreen.svg?style=flat-square)](https://ci.centos.org/job/purpleidea-mgmt/)
 
 ## Community:
-Come join us on IRC in [#mgmtconfig](https://webchat.freenode.net/?channels=#mgmtconfig) on Freenode!
-You may like the [#mgmtconfig](https://twitter.com/hashtag/mgmtconfig) hashtag if you're on [Twitter](https://twitter.com/#!/purpleidea).
+Come join us in the `mgmt` community!
+
+| Medium | Link |
+|---|---|
+| IRC | [#mgmtconfig](https://webchat.freenode.net/?channels=#mgmtconfig) on Freenode |
+| Twitter | [@mgmtconfig](https://twitter.com/mgmtconfig) & [#mgmtconfig](https://twitter.com/hashtag/mgmtconfig) |
+| Mailing list | [mgmtconfig-list@redhat.com](https://www.redhat.com/mailman/listinfo/mgmtconfig-list) |
 
 ## Status:
 Mgmt is a fairly new project.
@@ -21,35 +23,21 @@ We're working towards being minimally useful for production environments.
 We aren't feature complete for what we'd consider a 1.x release yet.
 With your help you'll be able to influence our design and get us there sooner!
 
-## Questions:
-Please join the [#mgmtconfig](https://webchat.freenode.net/?channels=#mgmtconfig) IRC community!
-If you have a well phrased question that might benefit others, consider asking it by sending a patch to the documentation [FAQ](https://github.com/purpleidea/mgmt/blob/master/docs/documentation.md#usage-and-frequently-asked-questions) section. I'll merge your question, and a patch with the answer!
-
-## Quick start:
-* Make sure you have golang version 1.6 or greater installed.
-* If you do not have a GOPATH yet, create one and export it:
-```
-mkdir $HOME/gopath
-export GOPATH=$HOME/gopath
-```
-* You might also want to add the GOPATH to your `~/.bashrc` or `~/.profile`.
-* For more information you can read the [GOPATH documentation](https://golang.org/cmd/go/#hdr-GOPATH_environment_variable).
-* Next download the mgmt code base, and switch to that directory:
-```
-go get -u github.com/purpleidea/mgmt
-cd $GOPATH/src/github.com/purpleidea/mgmt
-```
-* Get the remaining golang deps with `go get ./...`, or run `make deps` if you're comfortable with how we install them.
-* Run `make build` to get a freshly built `mgmt` binary.
-* Run `time ./mgmt run --yaml examples/graph0.yaml --converged-timeout=5 --tmp-prefix` to try out a very simple example!
-* To run continuously in the default mode of operation, omit the `--converged-timeout` option.
-* Have fun hacking on our future technology!
-
-## Examples:
-Please look in the [examples/](examples/) folder for more examples!
-
 ## Documentation:
-Please see: the manually created [documentation.md](docs/documentation.md) (also available as [PDF](https://pdfdoc-purpleidea.rhcloud.com/pdf/https://github.com/purpleidea/mgmt/blob/master/docs/documentation.md)) and the automatically generated [GoDoc documentation](https://godoc.org/github.com/purpleidea/mgmt).
+Please read, enjoy and help improve our documentation!
+
+| Documentation | Additional Notes |
+|---|---|
+| [general documentation](docs/documentation.md) | for everyone |
+| [quick start guide](docs/quick-start-guide.md) | for mgmt developers |
+| [resource guide](docs/resource-guide.md) | for mgmt developers |
+| [godoc API reference](https://godoc.org/github.com/purpleidea/mgmt) | for mgmt developers |
+| [prometheus guide](docs/prometheus.md) | for everyone |
+| [puppet guide](docs/puppet-guide.md) | for puppet sysadmins |
+
+## Questions:
+Please ask in the [community](#community)!
+If you have a well phrased question that might benefit others, consider asking it by sending a patch to the documentation [FAQ](https://github.com/purpleidea/mgmt/blob/master/docs/documentation.md#usage-and-frequently-asked-questions) section. I'll merge your question, and a patch with the answer!
 
 ## Roadmap:
 Please see: [TODO.md](TODO.md) for a list of upcoming work and TODO items.
@@ -61,52 +49,38 @@ Please set the `DEBUG` constant in [main.go](https://github.com/purpleidea/mgmt/
 Bonus points if you provide a [shell](https://github.com/purpleidea/mgmt/tree/master/test/shell) or [OMV](https://github.com/purpleidea/mgmt/tree/master/test/omv) reproducible test case.
 Feel free to read my article on [debugging golang programs](https://ttboj.wordpress.com/2016/02/15/debugging-golang-programs/).
 
-## Dependencies:
-* golang 1.6 or higher (required, available in most distros)
-* golang libraries (required, available with `go get`)
-```
-go get github.com/coreos/etcd/client
-go get gopkg.in/yaml.v2
-go get gopkg.in/fsnotify.v1
-go get github.com/urfave/cli
-go get github.com/coreos/go-systemd/dbus
-go get github.com/coreos/go-systemd/util
-go get github.com/coreos/pkg/capnslog
-go get github.com/rgbkrk/libvirt-go
-```
-* stringer (optional for building), available as a package on some platforms, otherwise via `go get`
-```
-go get golang.org/x/tools/cmd/stringer
-```
-* pandoc (optional, for building a pdf of the documentation)
-* graphviz (optional, for building a visual representation of the graph)
-
 ## Patches:
 We'd love to have your patches! Please send them by email, or as a pull request.
 
 ## On the web:
-* James Shubin; blog: [Next generation configuration mgmt](https://ttboj.wordpress.com/2016/01/18/next-generation-configuration-mgmt/)
-* James Shubin; video: [Introductory recording from DevConf.cz 2016](https://www.youtube.com/watch?v=GVhpPF0j-iE&html5=1)
-* James Shubin; video: [Introductory recording from CfgMgmtCamp.eu 2016](https://www.youtube.com/watch?v=fNeooSiIRnA&html5=1)
-* Julian Dunn; video: [On mgmt at CfgMgmtCamp.eu 2016](https://www.youtube.com/watch?v=kfF9IATUask&t=1949&html5=1)
-* Walter Heck; slides: [On mgmt at CfgMgmtCamp.eu 2016](http://www.slideshare.net/olindata/configuration-management-time-for-a-4th-generation/3)
-* Marco Marongiu; blog: [On mgmt](http://syslog.me/2016/02/15/leap-or-die/)
-* Felix Frank; blog: [From Catalog To Mgmt (on puppet to mgmt "transpiling")](https://ffrank.github.io/features/2016/02/18/from-catalog-to-mgmt/)
-* James Shubin; blog: [Automatic edges in mgmt (...and the pkg resource)](https://ttboj.wordpress.com/2016/03/14/automatic-edges-in-mgmt/)
-* James Shubin; blog: [Automatic grouping in mgmt](https://ttboj.wordpress.com/2016/03/30/automatic-grouping-in-mgmt/)
-* John Arundel; tweet: [“Puppet’s days are numbered.”](https://twitter.com/bitfield/status/732157519142002688)
-* Felix Frank; blog: [Puppet, Meet Mgmt (on puppet to mgmt internals)](https://ffrank.github.io/features/2016/06/12/puppet,-meet-mgmt/)
-* Felix Frank; blog: [Puppet Powered Mgmt (puppet to mgmt tl;dr)](https://ffrank.github.io/features/2016/06/19/puppet-powered-mgmt/)
-* James Shubin; blog: [Automatic clustering in mgmt](https://ttboj.wordpress.com/2016/06/20/automatic-clustering-in-mgmt/)
-* James Shubin; video: [Recording from CoreOSFest 2016](https://www.youtube.com/watch?v=KVmDCUA42wc&html5=1)
-* James Shubin; video: [Recording from DebConf16](http://meetings-archive.debian.net/pub/debian-meetings/2016/debconf16/Next_Generation_Config_Mgmt.webm) ([Slides](https://annex.debconf.org//debconf-share/debconf16/slides/15-next-generation-config-mgmt.pdf))
-* Felix Frank; blog: [Edging It All In (puppet and mgmt edges)](https://ffrank.github.io/features/2016/07/12/edging-it-all-in/)
-* Felix Frank; blog: [Translating All The Things (puppet to mgmt translation warnings)](https://ffrank.github.io/features/2016/08/19/translating-all-the-things/)
-* James Shubin; video: [Recording from systemd.conf 2016](https://www.youtube.com/watch?v=jB992Zb3nH0&html5=1)
-* James Shubin; blog: [Remote execution in mgmt](https://ttboj.wordpress.com/2016/10/07/remote-execution-in-mgmt/)
-* James Shubin; video: [Recording from High Load Strategy 2016](https://vimeo.com/191493409)
-* James Shubin; video: [Recording from NLUUG 2016](https://www.youtube.com/watch?v=MmpwOQAb_SE&html5=1)
-* James Shubin; blog: [Send/Recv in mgmt](https://ttboj.wordpress.com/2016/12/07/sendrecv-in-mgmt/)
+| Author | Format | Subject |
+|---|---|---|
+| James Shubin | blog | [Next generation configuration mgmt](https://ttboj.wordpress.com/2016/01/18/next-generation-configuration-mgmt/) |
+| James Shubin | video | [Introductory recording from DevConf.cz 2016](https://www.youtube.com/watch?v=GVhpPF0j-iE&html5=1) |
+| James Shubin | video | [Introductory recording from CfgMgmtCamp.eu 2016](https://www.youtube.com/watch?v=fNeooSiIRnA&html5=1) |
+| Julian Dunn | video | [On mgmt at CfgMgmtCamp.eu 2016](https://www.youtube.com/watch?v=kfF9IATUask&t=1949&html5=1) |
+| Walter Heck | slides | [On mgmt at CfgMgmtCamp.eu 2016](http://www.slideshare.net/olindata/configuration-management-time-for-a-4th-generation/3) |
+| Marco Marongiu | blog | [On mgmt](http://syslog.me/2016/02/15/leap-or-die/) |
+| Felix Frank | blog | [From Catalog To Mgmt (on puppet to mgmt "transpiling")](https://ffrank.github.io/features/2016/02/18/from-catalog-to-mgmt/) |
+| James Shubin | blog | [Automatic edges in mgmt (...and the pkg resource)](https://ttboj.wordpress.com/2016/03/14/automatic-edges-in-mgmt/) |
+| James Shubin | blog | [Automatic grouping in mgmt](https://ttboj.wordpress.com/2016/03/30/automatic-grouping-in-mgmt/) |
+| John Arundel | tweet | [“Puppet’s days are numbered.”](https://twitter.com/bitfield/status/732157519142002688) |
+| Felix Frank | blog | [Puppet, Meet Mgmt (on puppet to mgmt internals)](https://ffrank.github.io/features/2016/06/12/puppet,-meet-mgmt/) |
+| Felix Frank | blog | [Puppet Powered Mgmt (puppet to mgmt tl;dr)](https://ffrank.github.io/features/2016/06/19/puppet-powered-mgmt/) |
+| James Shubin | blog | [Automatic clustering in mgmt](https://ttboj.wordpress.com/2016/06/20/automatic-clustering-in-mgmt/) |
+| James Shubin | video | [Recording from CoreOSFest 2016](https://www.youtube.com/watch?v=KVmDCUA42wc&html5=1) |
+| James Shubin | video | [Recording from DebConf16](http://meetings-archive.debian.net/pub/debian-meetings/2016/debconf16/Next_Generation_Config_Mgmt.webm) ([Slides](https://annex.debconf.org//debconf-share/debconf16/slides/15-next-generation-config-mgmt.pdf)) |
+| Felix Frank | blog | [Edging It All In (puppet and mgmt edges)](https://ffrank.github.io/features/2016/07/12/edging-it-all-in/) |
+| Felix Frank | blog | [Translating All The Things (puppet to mgmt translation warnings)](https://ffrank.github.io/features/2016/08/19/translating-all-the-things/) |
+| James Shubin | video | [Recording from systemd.conf 2016](https://www.youtube.com/watch?v=jB992Zb3nH0&html5=1) |
+| James Shubin | blog | [Remote execution in mgmt](https://ttboj.wordpress.com/2016/10/07/remote-execution-in-mgmt/) |
+| James Shubin | video | [Recording from High Load Strategy 2016](https://vimeo.com/191493409) |
+| James Shubin | video | [Recording from NLUUG 2016](https://www.youtube.com/watch?v=MmpwOQAb_SE&html5=1) |
+| James Shubin | blog | [Send/Recv in mgmt](https://ttboj.wordpress.com/2016/12/07/sendrecv-in-mgmt/) |
+| James Shubin | blog | [Metaparameters in mgmt](https://ttboj.wordpress.com/2017/03/01/metaparameters-in-mgmt/) |
+| James Shubin | video | [Recording from Incontro DevOps 2017](https://vimeo.com/212241877) |
+| Yves Brissaud | blog | [mgmt aux HumanTalks Grenoble (french)](http://log.winsos.net/2017/04/12/mgmt-aux-human-talks-grenoble.html) |
+| James Shubin | video | [Recording from OSDC Berlin 2017](https://www.youtube.com/watch?v=LkEtBVLfygE&html5=1) |
 
 ##
 

TODO.md

@@ -1,16 +1,16 @@
 # TODO
 If you're looking for something to do, look here!
 Let us know if you're working on one of the items.
+If you'd like something to work on, ping @purpleidea and I'll create an issue
+tailored especially for you! Just let me know your approximate golang skill
+level and how many hours you'd like to spend on the patch.
 
 ## Package resource
 - [ ] getfiles support on debian [bug](https://github.com/hughsie/PackageKit/issues/118)
 - [ ] directory info on fedora [bug](https://github.com/hughsie/PackageKit/issues/117)
 - [ ] dnf blocker [bug](https://github.com/hughsie/PackageKit/issues/110)
-- [ ] install signal blocker [bug](https://github.com/hughsie/PackageKit/issues/109)
 
-## File resource [bug](https://github.com/purpleidea/mgmt/issues/13) [:heart:](https://github.com/purpleidea/mgmt/labels/mgmtlove)
-- [ ] chown/chmod support [:heart:](https://github.com/purpleidea/mgmt/labels/mgmtlove)
-- [ ] user/group support [:heart:](https://github.com/purpleidea/mgmt/labels/mgmtlove)
+## File resource [bug](https://github.com/purpleidea/mgmt/issues/64) [:heart:](https://github.com/purpleidea/mgmt/labels/mgmtlove)
 - [ ] recurse limit support [:heart:](https://github.com/purpleidea/mgmt/labels/mgmtlove)
 - [ ] fanotify support [bug](https://github.com/go-fsnotify/fsnotify/issues/114)
 
@@ -21,7 +21,6 @@ Let us know if you're working on one of the items.
 - [ ] base resource improvements
 
 ## Timer resource
-- [ ] reset on recompile
 - [ ] increment algorithm (linear, exponential, etc...) [:heart:](https://github.com/purpleidea/mgmt/labels/mgmtlove)
 
 ## User/Group resource
@@ -29,7 +28,7 @@ Let us know if you're working on one of the items.
 - [ ] automatic edges to file resource [:heart:](https://github.com/purpleidea/mgmt/labels/mgmtlove)
 
 ## Virt (libvirt) resource
-- [ ] base resource [bug](https://github.com/purpleidea/mgmt/issues/25)
+- [ ] base resource improvements [:heart:](https://github.com/purpleidea/mgmt/labels/mgmtlove)
 
 ## Net (systemd-networkd) resource
 - [ ] base resource
@@ -44,7 +43,7 @@ Let us know if you're working on one of the items.
 - [ ] base resource [:heart:](https://github.com/purpleidea/mgmt/labels/mgmtlove)
 
 ## Http resource
-- [ ] base resource
+- [ ] base resource [:heart:](https://github.com/purpleidea/mgmt/labels/mgmtlove)
 
 ## Etcd improvements
 - [ ] fix embedded etcd master race
@@ -52,6 +51,9 @@ Let us know if you're working on one of the items.
 ## Torrent/dht file transfer
 - [ ] base plumbing
 
+## GPG/Auth improvements
+- [ ] base plumbing
+
 ## Language improvements
 - [ ] language design
 - [ ] lexer/parser

Vagrantfile

@@ -0,0 +1,50 @@
+Vagrant.configure(2) do |config|
+	config.ssh.forward_agent = true
+	config.ssh.username = 'vagrant'
+	config.vm.network "private_network", ip: "192.168.219.2"
+
+	config.vm.synced_folder ".", "/vagrant", disabled: true
+
+	config.vm.define "mgmt-dev" do |instance|
+		instance.vm.box = "fedora/26-cloud-base"
+	end
+
+	config.vm.provider "virtualbox" do |v|
+		v.memory = 1536
+		v.cpus = 2
+	end
+	config.vm.provider "libvirt" do |v|
+		v.memory = 2048
+	end
+
+	config.vm.provision "file", source: "vagrant/motd", destination: ".motd"
+	config.vm.provision "shell", inline: "cp ~vagrant/.motd /etc/motd"
+
+	config.vm.provision "file", source: "vagrant/mgmt.bashrc", destination: ".mgmt.bashrc"
+	config.vm.provision "file", source: "~/.gitconfig", destination: ".gitconfig"
+
+	# copied from make-deps.sh (with added git)
+	config.vm.provision "shell", inline: "dnf install -y libvirt-devel golang golang-googlecode-tools-stringer hg git make"
+
+	# set up packagekit
+	config.vm.provision "shell" do |shell|
+		shell.inline = <<-SCRIPT
+			dnf install -y PackageKit
+			systemctl enable packagekit
+			systemctl start packagekit
+		SCRIPT
+	end
+
+	# set up vagrant home
+	script = <<-SCRIPT
+		grep -q 'mgmt\.bashrc' ~/.bashrc || echo '. ~/.mgmt.bashrc' >>~/.bashrc
+		. ~/.mgmt.bashrc
+		go get -u github.com/purpleidea/mgmt
+		cd ~/gopath/src/github.com/purpleidea/mgmt
+		make deps
+	SCRIPT
+	config.vm.provision "shell" do |shell|
+		shell.privileged = false
+		shell.inline = script
+	end
+end

converger/converger.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 // Package converger is a facility for reporting the converged state.
@@ -29,24 +29,24 @@ import (
 // TODO: we could make a new function that masks out the state of certain
 // UID's, but at the moment the new Timer code has obsoleted the need...
 
-// Converger is the general interface for implementing a convergence watcher
+// Converger is the general interface for implementing a convergence watcher.
 type Converger interface { // TODO: need a better name
-	Register() ConvergerUID
-	IsConverged(ConvergerUID) bool         // is the UID converged ?
-	SetConverged(ConvergerUID, bool) error // set the converged state of the UID
-	Unregister(ConvergerUID)
+	Register() UID
+	IsConverged(UID) bool         // is the UID converged ?
+	SetConverged(UID, bool) error // set the converged state of the UID
+	Unregister(UID)
 	Start()
 	Pause()
 	Loop(bool)
-	ConvergedTimer(ConvergerUID) <-chan time.Time
+	ConvergedTimer(UID) <-chan time.Time
 	Status() map[uint64]bool
 	Timeout() int                // returns the timeout that this was created with
 	SetStateFn(func(bool) error) // sets the stateFn
 }
 
-// ConvergerUID is the interface resources can use to notify with if converged
-// you'll need to use part of the Converger interface to Register initially too
-type ConvergerUID interface {
+// UID is the interface resources can use to notify with if converged. You'll
+// need to use part of the Converger interface to Register initially too.
+type UID interface {
 	ID() uint64   // get Id
 	Name() string // get a friendly name
 	SetName(string)
@@ -61,7 +61,7 @@ type ConvergerUID interface {
 	StopTimer() error
 }
 
-// converger is an implementation of the Converger interface
+// converger is an implementation of the Converger interface.
 type converger struct {
 	timeout   int              // must be zero (instant) or greater seconds to run
 	stateFn   func(bool) error // run on converged state changes with state bool
@@ -73,18 +73,19 @@ type converger struct {
 	status    map[uint64]bool
 }
 
-// convergerUID is an implementation of the ConvergerUID interface
-type convergerUID struct {
+// cuid is an implementation of the UID interface.
+type cuid struct {
 	converger Converger
 	id        uint64
 	name      string // user defined, friendly name
 	mutex     sync.Mutex
 	timer     chan struct{}
 	running   bool // is the above timer running?
+	wg        sync.WaitGroup
 }
 
-// NewConverger builds a new converger struct
-func NewConverger(timeout int, stateFn func(bool) error) *converger {
+// NewConverger builds a new converger struct.
+func NewConverger(timeout int, stateFn func(bool) error) Converger {
 	return &converger{
 		timeout: timeout,
 		stateFn: stateFn,
@@ -95,13 +96,13 @@ func NewConverger(timeout int, stateFn func(bool) error) *converger {
 	}
 }
 
-// Register assigns a ConvergerUID to the caller
-func (obj *converger) Register() ConvergerUID {
+// Register assigns a UID to the caller.
+func (obj *converger) Register() UID {
 	obj.mutex.Lock()
 	defer obj.mutex.Unlock()
 	obj.lastid++
 	obj.status[obj.lastid] = false // initialize as not converged
-	return &convergerUID{
+	return &cuid{
 		converger: obj,
 		id:        obj.lastid,
 		name:      fmt.Sprintf("%d", obj.lastid), // some default
@@ -110,28 +111,28 @@ func (obj *converger) Register() ConvergerUID {
 	}
 }
 
-// IsConverged gets the converged status of a uid
-func (obj *converger) IsConverged(uid ConvergerUID) bool {
+// IsConverged gets the converged status of a uid.
+func (obj *converger) IsConverged(uid UID) bool {
 	if !uid.IsValid() {
-		panic(fmt.Sprintf("Id of ConvergerUID(%s) is nil!", uid.Name()))
+		panic(fmt.Sprintf("the ID of UID(%s) is nil", uid.Name()))
 	}
 	obj.mutex.RLock()
 	isConverged, found := obj.status[uid.ID()] // lookup
 	obj.mutex.RUnlock()
 	if !found {
-		panic("Id of ConvergerUID is unregistered!")
+		panic("the ID of UID is unregistered")
 	}
 	return isConverged
 }
 
-// SetConverged updates the converger with the converged state of the UID
-func (obj *converger) SetConverged(uid ConvergerUID, isConverged bool) error {
+// SetConverged updates the converger with the converged state of the UID.
+func (obj *converger) SetConverged(uid UID, isConverged bool) error {
 	if !uid.IsValid() {
-		return fmt.Errorf("Id of ConvergerUID(%s) is nil!", uid.Name())
+		return fmt.Errorf("the ID of UID(%s) is nil", uid.Name())
 	}
 	obj.mutex.Lock()
 	if _, found := obj.status[uid.ID()]; !found {
-		panic("Id of ConvergerUID is unregistered!")
+		panic("the ID of UID is unregistered")
 	}
 	obj.status[uid.ID()] = isConverged // set
 	obj.mutex.Unlock()                 // unlock *before* poke or deadlock!
@@ -143,7 +144,7 @@ func (obj *converger) SetConverged(uid ConvergerUID, isConverged bool) error {
 	return nil
 }
 
-// isConverged returns true if *every* registered uid has converged
+// isConverged returns true if *every* registered uid has converged.
 func (obj *converger) isConverged() bool {
 	obj.mutex.RLock() // take a read lock
 	defer obj.mutex.RUnlock()
@@ -155,10 +156,10 @@ func (obj *converger) isConverged() bool {
 	return true
 }
 
-// Unregister dissociates the ConvergedUID from the converged checking
-func (obj *converger) Unregister(uid ConvergerUID) {
+// Unregister dissociates the ConvergedUID from the converged checking.
+func (obj *converger) Unregister(uid UID) {
 	if !uid.IsValid() {
-		panic(fmt.Sprintf("Id of ConvergerUID(%s) is nil!", uid.Name()))
+		panic(fmt.Sprintf("the ID of UID(%s) is nil", uid.Name()))
 	}
 	obj.mutex.Lock()
 	uid.StopTimer() // ignore any errors
@@ -167,30 +168,30 @@ func (obj *converger) Unregister(uid ConvergerUID) {
 	uid.InvalidateID()
 }
 
-// Start causes a Converger object to start or resume running
+// Start causes a Converger object to start or resume running.
 func (obj *converger) Start() {
 	obj.control <- true
 }
 
-// Pause causes a Converger object to stop running temporarily
+// Pause causes a Converger object to stop running temporarily.
 func (obj *converger) Pause() { // FIXME: add a sync ACK on pause before return
 	obj.control <- false
 }
 
-// Loop is the main loop for a Converger object; it usually runs in a goroutine
-// TODO: we could eventually have each resource tell us as soon as it converges
-// and then keep track of the time delays here, to avoid callers needing select
+// Loop is the main loop for a Converger object. It usually runs in a goroutine.
+// TODO: we could eventually have each resource tell us as soon as it converges,
+// and then keep track of the time delays here, to avoid callers needing select.
 // NOTE: when we have very short timeouts, if we start before all the resources
-// have joined the map, then it might appears as if we converged before we did!
+// have joined the map, then it might appear as if we converged before we did!
 func (obj *converger) Loop(startPaused bool) {
 	if obj.control == nil {
-		panic("Converger not initialized correctly")
+		panic("converger not initialized correctly")
 	}
 	if startPaused { // start paused without racing
 		select {
 		case e := <-obj.control:
 			if !e {
-				panic("Converger expected true!")
+				panic("converger expected true")
 			}
 		}
 	}
@@ -198,13 +199,13 @@ func (obj *converger) Loop(startPaused bool) {
 		select {
 		case e := <-obj.control: // expecting "false" which means pause!
 			if e {
-				panic("Converger expected false!")
+				panic("converger expected false")
 			}
 			// now i'm paused...
 			select {
 			case e := <-obj.control:
 				if !e {
-					panic("Converger expected true!")
+					panic("converger expected true")
 				}
 				// restart
 				// kick once to refresh the check...
@@ -243,9 +244,9 @@ func (obj *converger) Loop(startPaused bool) {
 	}
 }
 
-// ConvergedTimer adds a timeout to a select call and blocks until then
+// ConvergedTimer adds a timeout to a select call and blocks until then.
 // TODO: this means we could eventually have per resource converged timeouts
-func (obj *converger) ConvergedTimer(uid ConvergerUID) <-chan time.Time {
+func (obj *converger) ConvergedTimer(uid UID) <-chan time.Time {
 	// be clever: if i'm already converged, this timeout should block which
 	// avoids unnecessary new signals being sent! this avoids fast loops if
 	// we have a low timeout, or in particular a timeout == 0
@@ -279,63 +280,65 @@ func (obj *converger) SetStateFn(stateFn func(bool) error) {
 	obj.stateFn = stateFn
 }
 
-// Id returns the unique id of this UID object
-func (obj *convergerUID) ID() uint64 {
+// ID returns the unique id of this UID object.
+func (obj *cuid) ID() uint64 {
 	return obj.id
 }
 
-// Name returns a user defined name for the specific convergerUID.
-func (obj *convergerUID) Name() string {
+// Name returns a user defined name for the specific cuid.
+func (obj *cuid) Name() string {
 	return obj.name
 }
 
-// SetName sets a user defined name for the specific convergerUID.
-func (obj *convergerUID) SetName(name string) {
+// SetName sets a user defined name for the specific cuid.
+func (obj *cuid) SetName(name string) {
 	obj.name = name
 }
 
-// IsValid tells us if the id is valid or has already been destroyed
-func (obj *convergerUID) IsValid() bool {
+// IsValid tells us if the id is valid or has already been destroyed.
+func (obj *cuid) IsValid() bool {
 	return obj.id != 0 // an id of 0 is invalid
 }
 
-// InvalidateID marks the id as no longer valid
-func (obj *convergerUID) InvalidateID() {
+// InvalidateID marks the id as no longer valid.
+func (obj *cuid) InvalidateID() {
 	obj.id = 0 // an id of 0 is invalid
 }
 
-// IsConverged is a helper function to the regular IsConverged method
-func (obj *convergerUID) IsConverged() bool {
+// IsConverged is a helper function to the regular IsConverged method.
+func (obj *cuid) IsConverged() bool {
 	return obj.converger.IsConverged(obj)
 }
 
-// SetConverged is a helper function to the regular SetConverged notification
-func (obj *convergerUID) SetConverged(isConverged bool) error {
+// SetConverged is a helper function to the regular SetConverged notification.
+func (obj *cuid) SetConverged(isConverged bool) error {
 	return obj.converger.SetConverged(obj, isConverged)
 }
 
-// Unregister is a helper function to unregister myself
-func (obj *convergerUID) Unregister() {
+// Unregister is a helper function to unregister myself.
+func (obj *cuid) Unregister() {
 	obj.converger.Unregister(obj)
 }
 
-// ConvergedTimer is a helper around the regular ConvergedTimer method
-func (obj *convergerUID) ConvergedTimer() <-chan time.Time {
+// ConvergedTimer is a helper around the regular ConvergedTimer method.
+func (obj *cuid) ConvergedTimer() <-chan time.Time {
 	return obj.converger.ConvergedTimer(obj)
 }
 
 // StartTimer runs an invisible timer that automatically converges on timeout.
-func (obj *convergerUID) StartTimer() (func() error, error) {
+func (obj *cuid) StartTimer() (func() error, error) {
 	obj.mutex.Lock()
 	if !obj.running {
 		obj.timer = make(chan struct{})
 		obj.running = true
 	} else {
 		obj.mutex.Unlock()
-		return obj.StopTimer, fmt.Errorf("Timer already started!")
+		return obj.StopTimer, fmt.Errorf("timer already started")
 	}
 	obj.mutex.Unlock()
+	obj.wg.Add(1)
 	go func() {
+		defer obj.wg.Done()
 		for {
 			select {
 			case _, ok := <-obj.timer: // reset signal channel
@@ -359,24 +362,25 @@ func (obj *convergerUID) StartTimer() (func() error, error) {
 }
 
 // ResetTimer resets the counter to zero if using a StartTimer internally.
-func (obj *convergerUID) ResetTimer() error {
+func (obj *cuid) ResetTimer() error {
 	obj.mutex.Lock()
 	defer obj.mutex.Unlock()
 	if obj.running {
 		obj.timer <- struct{}{} // send the reset message
 		return nil
 	}
-	return fmt.Errorf("Timer hasn't been started!")
+	return fmt.Errorf("timer hasn't been started")
 }
 
 // StopTimer stops the running timer permanently until a StartTimer is run.
-func (obj *convergerUID) StopTimer() error {
+func (obj *cuid) StopTimer() error {
 	obj.mutex.Lock()
 	defer obj.mutex.Unlock()
 	if !obj.running {
-		return fmt.Errorf("Timer isn't running!")
+		return fmt.Errorf("timer isn't running")
 	}
 	close(obj.timer)
+	obj.wg.Wait()
 	obj.running = false
 	return nil
 }

doc.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 // Package main provides the main entrypoint for using the `mgmt` software.

docs/.gitignore

@@ -1 +1,2 @@
 mgmt-documentation.pdf
+_build

docs/Makefile

@@ -0,0 +1,20 @@
+# Minimal makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line.
+SPHINXOPTS    =
+SPHINXBUILD   = sphinx-build
+SPHINXPROJ    = mgmt
+SOURCEDIR     = .
+BUILDDIR      = _build
+
+# Put it first so that "make" without argument is like "make help".
+help:
+	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+
+.PHONY: help Makefile
+
+# Catch-all target: route all unknown targets to Sphinx using the new
+# "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
+%: Makefile
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)

docs/conf.py

@@ -0,0 +1,158 @@
+# -*- coding: utf-8 -*-
+#
+# mgmt documentation build configuration file, created by
+# sphinx-quickstart on Wed Feb 15 21:34:09 2017.
+#
+# This file is execfile()d with the current directory set to its
+# containing dir.
+#
+# Note that not all possible configuration values are present in this
+# autogenerated file.
+#
+# All configuration values have a default; values that are commented out
+# serve to show the default.
+
+# If extensions (or modules to document with autodoc) are in another directory,
+# add these directories to sys.path here. If the directory is relative to the
+# documentation root, use os.path.abspath to make it absolute, like shown here.
+#
+# import os
+# import sys
+# sys.path.insert(0, os.path.abspath('.'))
+
+from recommonmark.parser import CommonMarkParser
+
+# -- General configuration ------------------------------------------------
+
+# If your documentation needs a minimal Sphinx version, state it here.
+#
+# needs_sphinx = '1.0'
+
+# Add any Sphinx extension module names here, as strings. They can be
+# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
+# ones.
+extensions = []
+
+# Add any paths that contain templates here, relative to this directory.
+templates_path = ['_templates']
+
+# The suffix(es) of source filenames.
+# You can specify multiple suffix as a list of string:
+#
+
+source_parsers = {
+        '.md': CommonMarkParser,
+}
+
+source_suffix = ['.rst', '.md']
+
+# The master toctree document.
+master_doc = 'index'
+
+# General information about the project.
+project = u'mgmt'
+copyright = u'2013-2017+ James Shubin and the project contributors'
+author = u'James Shubin'
+
+# The version info for the project you're documenting, acts as replacement for
+# |version| and |release|, also used in various other places throughout the
+# built documents.
+#
+# The short X.Y version.
+version = u''
+# The full version, including alpha/beta/rc tags.
+release = u''
+
+# The language for content autogenerated by Sphinx. Refer to documentation
+# for a list of supported languages.
+#
+# This is also used if you do content translation via gettext catalogs.
+# Usually you set "language" from the command line for these cases.
+language = None
+
+# List of patterns, relative to source directory, that match files and
+# directories to ignore when looking for source files.
+# This patterns also effect to html_static_path and html_extra_path
+exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store', 'venv']
+
+# The name of the Pygments (syntax highlighting) style to use.
+pygments_style = 'sphinx'
+
+# If true, `todo` and `todoList` produce output, else they produce nothing.
+todo_include_todos = False
+
+
+# -- Options for HTML output ----------------------------------------------
+
+# The theme to use for HTML and HTML Help pages.  See the documentation for
+# a list of builtin themes.
+#
+#html_theme = 'alabaster'
+
+# Theme options are theme-specific and customize the look and feel of a theme
+# further.  For a list of options available for each theme, see the
+# documentation.
+#
+# html_theme_options = {}
+
+# Add any paths that contain custom static files (such as style sheets) here,
+# relative to this directory. They are copied after the builtin static files,
+# so a file named "default.css" will overwrite the builtin "default.css".
+html_static_path = ['_static']
+
+
+# -- Options for HTMLHelp output ------------------------------------------
+
+# Output file base name for HTML help builder.
+htmlhelp_basename = 'mgmtdoc'
+
+
+# -- Options for LaTeX output ---------------------------------------------
+
+latex_elements = {
+    # The paper size ('letterpaper' or 'a4paper').
+    #
+    # 'papersize': 'letterpaper',
+
+    # The font size ('10pt', '11pt' or '12pt').
+    #
+    # 'pointsize': '10pt',
+
+    # Additional stuff for the LaTeX preamble.
+    #
+    # 'preamble': '',
+
+    # Latex figure (float) alignment
+    #
+    # 'figure_align': 'htbp',
+}
+
+# Grouping the document tree into LaTeX files. List of tuples
+# (source start file, target name, title,
+#  author, documentclass [howto, manual, or own class]).
+latex_documents = [
+    (master_doc, 'mgmt.tex', u'mgmt Documentation',
+     u'James Shubin', 'manual'),
+]
+
+
+# -- Options for manual page output ---------------------------------------
+
+# One entry per manual page. List of tuples
+# (source start file, name, description, authors, manual section).
+man_pages = [
+    (master_doc, 'mgmt', u'mgmt Documentation',
+     [author], 1)
+]
+
+
+# -- Options for Texinfo output -------------------------------------------
+
+# Grouping the document tree into Texinfo files. List of tuples
+# (source start file, target name, title, author,
+#  dir menu entry, description, category)
+texinfo_documents = [
+    (master_doc, 'mgmt', u'mgmt Documentation',
+     author, 'mgmt', 'A next generation config management prototype!',
+     'Miscellaneous'),
+]

docs/documentation.md

@@ -1,57 +1,16 @@
-#mgmt
+# mgmt
 
-<!--
-Mgmt
-Copyright (C) 2013-2016+ James Shubin and the project contributors
-Written by James Shubin <james@shubin.ca> and the project contributors
+Available from:
+[https://github.com/purpleidea/mgmt/](https://github.com/purpleidea/mgmt/)
 
-This program is free software: you can redistribute it and/or modify
-it under the terms of the GNU Affero General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-(at your option) any later version.
+This documentation is available in: [Markdown](https://github.com/purpleidea/mgmt/blob/master/docs/documentation.md) or [PDF](https://pdfdoc-purpleidea.rhcloud.com/pdf/https://github.com/purpleidea/mgmt/blob/master/docs/documentation.md) format.
 
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU Affero General Public License for more details.
-
-You should have received a copy of the GNU Affero General Public License
-along with this program.  If not, see <http://www.gnu.org/licenses/>.
--->
-
-##mgmt by [James](https://ttboj.wordpress.com/)
-####Available from:
-####[https://github.com/purpleidea/mgmt/](https://github.com/purpleidea/mgmt/)
-
-####This documentation is available in: [Markdown](https://github.com/purpleidea/mgmt/blob/master/docs/documentation.md) or [PDF](https://pdfdoc-purpleidea.rhcloud.com/pdf/https://github.com/purpleidea/mgmt/blob/master/docs/documentation.md) format.
-
-####Table of Contents
-
-1. [Overview](#overview)
-2. [Project description - What the project does](#project-description)
-3. [Setup - Getting started with mgmt](#setup)
-4. [Features - All things mgmt can do](#features)
-	* [Autoedges - Automatic resource relationships](#autoedges)
-	* [Autogrouping - Automatic resource grouping](#autogrouping)
-	* [Automatic clustering - Automatic cluster management](#automatic-clustering)
-	* [Remote mode - Remote "agent-less" execution](#remote-agent-less-mode)
-	* [Puppet support - write manifest code for mgmt](#puppet-support)
-5. [Resources - All built-in primitives](#resources)
-6. [Usage/FAQ - Notes on usage and frequently asked questions](#usage-and-frequently-asked-questions)
-7. [Reference - Detailed reference](#reference)
-	* [Meta parameters](#meta-parameters)
-	* [Graph definition file](#graph-definition-file)
-	* [Command line](#command-line)
-8. [Examples - Example configurations](#examples)
-9. [Development - Background on module development and reporting bugs](#development)
-10. [Authors - Authors and contact information](#authors)
-
-##Overview
+## Overview
 
 The `mgmt` tool is a next generation config management prototype. It's not yet
 ready for production, but we hope to get there soon. Get involved today!
 
-##Project Description
+## Project Description
 
 The mgmt tool is a distributed, event driven, config management tool, that
 supports parallel execution, and librarification to be used as the management
@@ -63,11 +22,14 @@ For more information, you may like to read some blog posts from the author:
 * [Automatic edges in mgmt](https://ttboj.wordpress.com/2016/03/14/automatic-edges-in-mgmt/)
 * [Automatic grouping in mgmt](https://ttboj.wordpress.com/2016/03/30/automatic-grouping-in-mgmt/)
 * [Automatic clustering in mgmt](https://ttboj.wordpress.com/2016/06/20/automatic-clustering-in-mgmt/)
+* [Remote execution in mgmt](https://ttboj.wordpress.com/2016/10/07/remote-execution-in-mgmt/)
+* [Send/Recv in mgmt](https://ttboj.wordpress.com/2016/12/07/sendrecv-in-mgmt/)
+* [Metaparameters in mgmt](https://ttboj.wordpress.com/2017/03/01/metaparameters-in-mgmt/)
 
 There is also an [introductory video](http://meetings-archive.debian.net/pub/debian-meetings/2016/debconf16/Next_Generation_Config_Mgmt.webm) available.
 Older videos and other material [is available](https://github.com/purpleidea/mgmt/#on-the-web).
 
-##Setup
+## Setup
 
 During this prototype phase, the tool can be run out of the source directory.
 You'll probably want to use ```./run.sh run --yaml examples/graph1.yaml``` to
@@ -75,12 +37,12 @@ get started. Beware that this _can_ cause data loss. Understand what you're
 doing first, or perform these actions in a virtual environment such as the one
 provided by [Oh-My-Vagrant](https://github.com/purpleidea/oh-my-vagrant).
 
-##Features
+## Features
 
 This section details the numerous features of mgmt and some caveats you might
 need to be aware of.
 
-###Autoedges
+### Autoedges
 
 Automatic edges, or AutoEdges, is the mechanism in mgmt by which it will
 automatically create dependencies for you between resources. For example,
@@ -89,7 +51,7 @@ automatically ensure that any file resource you declare that matches a
 file installed by your package resource will only be processed after the
 package is installed.
 
-####Controlling autoedges
+#### Controlling autoedges
 
 Though autoedges is likely to be very helpful and avoid you having to declare
 all dependencies explicitly, there are cases where this behaviour is
@@ -106,12 +68,12 @@ installation of the `mysql-server` package.
 You can disable autoedges for a resource by setting the `autoedge` key on
 the meta attributes of that resource to `false`.
 
-####Blog post
+#### Blog post
 
 You can read the introductory blog post about this topic here:
 [https://ttboj.wordpress.com/2016/03/14/automatic-edges-in-mgmt/](https://ttboj.wordpress.com/2016/03/14/automatic-edges-in-mgmt/)
 
-###Autogrouping
+### Autogrouping
 
 Automatic grouping or AutoGroup is the mechanism in mgmt by which it will
 automatically group multiple resource vertices into a single one. This is
@@ -125,12 +87,12 @@ used for other use cases too.
 You can disable autogrouping for a resource by setting the `autogroup` key on
 the meta attributes of that resource to `false`.
 
-####Blog post
+#### Blog post
 
 You can read the introductory blog post about this topic here:
 [https://ttboj.wordpress.com/2016/03/30/automatic-grouping-in-mgmt/](https://ttboj.wordpress.com/2016/03/30/automatic-grouping-in-mgmt/)
 
-###Automatic clustering
+### Automatic clustering
 
 Automatic clustering is a feature by which mgmt automatically builds, scales,
 and manages the embedded etcd cluster which is compiled into mgmt itself. It is
@@ -141,12 +103,12 @@ If you prefer to avoid this feature. you can always opt to use an existing etcd
 cluster that is managed separately from mgmt by pointing your mgmt agents at it
 with the `--seeds` variable.
 
-####Blog post
+#### Blog post
 
 You can read the introductory blog post about this topic here:
 [https://ttboj.wordpress.com/2016/06/20/automatic-clustering-in-mgmt/](https://ttboj.wordpress.com/2016/06/20/automatic-clustering-in-mgmt/)
 
-###Remote ("agent-less") mode
+### Remote ("agent-less") mode
 
 Remote mode is a special mode that lets you kick off mgmt runs on one or more
 remote machines which are only accessible via SSH. In this mode the initiating
@@ -168,12 +130,12 @@ entire set of running mgmt agents will need to all simultaneously converge for
 the group to exit. This is particularly useful for bootstrapping new clusters
 which need to exchange information that is only available at run time.
 
-####Blog post
+#### Blog post
 
 You can read the introductory blog post about this topic here:
 [https://ttboj.wordpress.com/2016/10/07/remote-execution-in-mgmt/](https://ttboj.wordpress.com/2016/10/07/remote-execution-in-mgmt/)
 
-###Puppet support
+### Puppet support
 
 You can supply a Puppet manifest instead of creating the (YAML) graph manually.
 Puppet must be installed and in `mgmt`'s search path. You also need the
@@ -195,12 +157,12 @@ Invoke `mgmt` with the `--puppet` switch, which supports 3 variants:
 
 For more details and caveats see [Puppet.md](Puppet.md).
 
-####Blog post
+#### Blog post
 
 An introductory post on the Puppet support is on
 [Felix's blog](http://ffrank.github.io/features/2016/06/19/puppet-powered-mgmt/).
 
-##Resources
+## Resources
 
 This section lists all the built-in resources and their properties. The
 resource primitives in `mgmt` are typically more powerful than resources in
@@ -216,9 +178,11 @@ meta parameters aren't very useful when combined with certain resources, but
 in general, it should be fairly obvious, such as when combining the `noop` meta
 parameter with the [Noop](#Noop) resource.
 
+* [Augeas](#Augeas): Manipulate files using augeas.
 * [Exec](#Exec): Execute shell commands on the system.
 * [File](#File): Manage files and directories.
 * [Hostname](#Hostname): Manages the hostname on the system.
+* [KV](#KV): Set a key value pair in our shared world database.
 * [Msg](#Msg): Send log messages.
 * [Noop](#Noop): A simple resource that does nothing.
 * [Nspawn](#Nspawn): Manage systemd-machined nspawn containers.
@@ -228,45 +192,60 @@ parameter with the [Noop](#Noop) resource.
 * [Timer](#Timer): Manage system systemd services.
 * [Virt](#Virt): Manage virtual machines with libvirt.
 
-###Exec
+
+### Augeas
+
+The augeas resource uses [augeas](http://augeas.net/) commands to manipulate
+files.
+
+### Exec
 
 The exec resource can execute commands on your system.
 
-###File
+### File
 
 The file resource manages files and directories. In `mgmt`, directories are
 identified by a trailing slash in their path name. File have no such slash.
 
-####Path
+It has the following properties:
+
+- `path`: file path (directories have a trailing slash here)
+- `content`: raw file content
+- `state`: either `exists` (the default value) or `absent`
+- `mode`: octal unix file permissions
+- `owner`: username or uid for the file owner
+- `group`: group name or gid for the file group
+
+#### Path
 
 The path property specifies the file or directory that we are managing.
 
-####Content
+#### Content
 
 The content property is a string that specifies the desired file contents.
 
-####Source
+#### Source
 
 The source property points to a source file or directory path that we wish to
 copy over and use as the desired contents for our resource.
 
-####State
+#### State
 
 The state property describes the action we'd like to apply for the resource. The
 possible values are: `exists` and `absent`.
 
-####Recurse
+#### Recurse
 
 The recurse property limits whether file resource operations should recurse into
 and monitor directory contents with a depth greater than one.
 
-####Force
+#### Force
 
 The force property is required if we want the file resource to be able to change
 a file into a directory or vice-versa. If such a change is needed, but the force
 property is not set to `true`, then this file resource will error.
 
-###Hostname
+### Hostname
 
 The hostname resource manages static, transient/dynamic and pretty hostnames
 on the system and watches them for changes.
@@ -290,55 +269,79 @@ The pretty hostname is a free-form UTF8 host name for presentation to the user.
 Hostname is the fallback value for all 3 fields above, if only `hostname` is
 specified, it will set all 3 fields to this value.
 
-###Msg
+### KV
+
+The KV resource sets a key and value pair in the global world database. This is
+quite useful for setting a flag after a number of resources have run. It will
+ignore database updates to the value that are greater in compare order than the
+requested key if the `SkipLessThan` parameter is set to true. If we receive a
+refresh, then the stored value will be reset to the requested value even if the
+stored value is greater.
+
+#### Key
+The string key used to store the key.
+
+#### Value
+The string value to set. This can also be set via Send/Recv.
+
+#### SkipLessThan
+If this parameter is set to `true`, then it will ignore updating the value as
+long as the database versions are greater than the requested value. The compare
+operation used is based on the `SkipCmpStyle` parameter.
+
+#### SkipCmpStyle
+By default this converts the string values to integers and compares them as you
+would expect.
+
+### Msg
 
 The msg resource sends messages to the main log, or an external service such
 as systemd's journal.
 
-###Noop
+### Noop
 
 The noop resource does absolutely nothing. It does have some utility in testing
 `mgmt` and also as a placeholder in the resource graph.
 
-###Nspawn
+### Nspawn
 
 The nspawn resource is used to manage systemd-machined style containers.
 
-###Password
+### Password
 
 The password resource can generate a random string to be used as a password. It
 will re-generate the password if it receives a refresh notification.
 
-###Pkg
+### Pkg
 
 The pkg resource is used to manage system packages. This resource works on many
 different distributions because it uses the underlying packagekit facility which
 supports different backends for different environments. This ensures that we
 have great Debian (deb/dpkg) and Fedora (rpm/dnf) support simultaneously.
 
-###Svc
+### Svc
 
 The service resource is still very WIP. Please help us my improving it!
 
-###Timer
+### Timer
 
 This resource needs better documentation. Please help us my improving it!
 
-###Virt
+### Virt
 
 The virt resource can manage virtual machines via libvirt.
 
-##Usage and frequently asked questions
+## Usage and frequently asked questions
 (Send your questions as a patch to this FAQ! I'll review it, merge it, and
 respond by commit with the answer.)
 
-###Why did you start this project?
+### Why did you start this project?
 
 I wanted a next generation config management solution that didn't have all of
 the design flaws or limitations that the current generation of tools do, and no
 tool existed!
 
-###Why did you use etcd? What about consul?
+### Why did you use etcd? What about consul?
 
 Etcd and consul are both written in golang, which made them the top two
 contenders for my prototype. Ultimately a choice had to be made, and etcd was
@@ -346,7 +349,7 @@ chosen, but it was also somewhat arbitrary. If there is available interest,
 good reasoning, *and* patches, then we would consider either switching or
 supporting both, but this is not a high priority at this time.
 
-###Can I use an existing etcd cluster instead of the automatic embedded servers?
+### Can I use an existing etcd cluster instead of the automatic embedded servers?
 
 Yes, it's possible to use an existing etcd cluster instead of the automatic,
 elastic embedded etcd servers. To do so, simply point to the cluster with the
@@ -357,7 +360,7 @@ The downside to this approach is that you won't benefit from the automatic
 elastic nature of the embedded etcd servers, and that you're responsible if you
 accidentally break your etcd cluster, or if you use an unsupported version.
 
-###What does the error message about an inconsistent dataDir mean?
+### What does the error message about an inconsistent dataDir mean?
 
 If you get an error message similar to:
 
@@ -375,7 +378,7 @@ starting up, and as a result, a default endpoint never gets added. The solution
 is to either reconcile the mistake, and if there is no important data saved, you
 can remove the etcd dataDir. This is typically `/var/lib/mgmt/etcd/member/`.
 
-###Why do resources have both a `Compare` method and an `IFF` (on the UID) method?
+### Why do resources have both a `Compare` method and an `IFF` (on the UID) method?
 
 The `Compare()` methods are for determining if two resources are effectively the
 same, which is used to make graph change delta's efficient. This is when we want
@@ -391,14 +394,14 @@ equality. In the future it might be helpful or sane to merge the two similar
 comparison functions although for now they are separate because they are
 actually answer different questions.
 
-###Did you know that there is a band named `MGMT`?
+### Did you know that there is a band named `MGMT`?
 
 I didn't realize this when naming the project, and it is accidental. After much
 anguishing, I chose the name because it was short and I thought it was
 appropriately descriptive. If you need a less ambiguous search term or phrase,
 you can try using `mgmtconfig` or `mgmt config`.
 
-###You didn't answer my question, or I have a question!
+### You didn't answer my question, or I have a question!
 
 It's best to ask on [IRC](https://webchat.freenode.net/?channels=#mgmtconfig)
 to see if someone can help you. Once we get a big enough community going, we'll
@@ -408,40 +411,41 @@ and I'll do my best to help. If you have a good question, please add it as a
 patch to this documentation. I'll merge your question, and add a patch with the
 answer!
 
-##Reference
+## Reference
 Please note that there are a number of undocumented options. For more
 information on these options, please view the source at:
 [https://github.com/purpleidea/mgmt/](https://github.com/purpleidea/mgmt/).
 If you feel that a well used option needs documenting here, please patch it!
 
-###Overview of reference
+### Overview of reference
 * [Meta parameters](#meta-parameters): List of available resource meta parameters.
 * [Graph definition file](#graph-definition-file): Main graph definition file.
 * [Command line](#command-line): Command line parameters.
+* [Compilation options](#compilation-options): Compilation options.
 
-###Meta parameters
+### Meta parameters
 These meta parameters are special parameters (or properties) which can apply to
 any resource. The usefulness of doing so will depend on the particular meta
 parameter and resource combination.
 
-####AutoEdge
+#### AutoEdge
 Boolean. Should we generate auto edges for this resource?
 
-####AutoGroup
+#### AutoGroup
 Boolean. Should we attempt to automatically group this resource with others?
 
-####Noop
+#### Noop
 Boolean. Should the Apply portion of the CheckApply method of the resource
 make any changes? Noop is a concatenation of no-operation.
 
-####Retry
+#### Retry
 Integer. The number of times to retry running the resource on error. Use -1 for
 infinite. This currently applies for both the Watch operation (which can fail)
 and for the CheckApply operation. While they could have separate values, I've
 decided to use the same ones for both until there's a proper reason to want to
 do something differently for the Watch errors.
 
-####Delay
+#### Delay
 Integer. Number of milliseconds to wait between retries. The same value is
 shared between the Watch and CheckApply retries. This currently applies for both
 the Watch operation (which can fail) and for the CheckApply operation. While
@@ -449,63 +453,113 @@ they could have separate values, I've decided to use the same ones for both
 until there's a proper reason to want to do something differently for the Watch
 errors.
 
-###Graph definition file
+#### Poll
+Integer. Number of seconds to wait between `CheckApply` checks. If this is
+greater than zero, then the standard event based `Watch` mechanism for this
+resource is replaced with a simple polling mechanism. In general, this is not
+recommended, unless you have a very good reason for doing so.
+
+Please keep in mind that if you have a resource which changes every `I` seconds,
+and you poll it every `J` seconds, and you've asked for a converged timeout of
+`K` seconds, and `I <= J <= K`, then your graph will likely never converge.
+
+When polling, the system detects that a resource is not converged if its
+`CheckApply` method returns false. This allows a resource which changes every
+`I` seconds, and which is polled every `J` seconds, and with a converged timeout
+of `K` seconds to still converge when `J <= K`, as long as `I > J || I > K`,
+which is another way of saying that if the resource finally settles down to give
+the graph enough time, it can probably converge.
+
+#### Limit
+Float. Maximum rate of `CheckApply` runs started per second. Useful to limit
+an especially _eventful_ process from causing excessive checks to run. This
+defaults to `+Infinity` which adds no limiting. If you change this value, you
+will also need to change the `Burst` value to a non-zero value. Please see the
+[rate](https://godoc.org/golang.org/x/time/rate) package for more information.
+
+#### Burst
+Integer. Burst is the maximum number of runs which can happen without invoking
+the rate limiter as designated by the `Limit` value. If the `Limit` is not set
+to `+Infinity`, this must be a non-zero value. Please see the
+[rate](https://godoc.org/golang.org/x/time/rate) package for more information.
+
+#### Sema
+List of string ids. Sema is a P/V style counting semaphore which can be used to
+limit parallelism during the CheckApply phase of resource execution. Each
+resource can have `N` different semaphores which share a graph global namespace.
+Each semaphore has a maximum count associated with it. The default value of the
+size is 1 (one) if size is unspecified. Each string id is the unique id of the
+semaphore. If the id contains a trailing colon (:) followed by a positive
+integer, then that value is the max size for that semaphore. Valid semaphore
+id's include: `some_id`, `hello:42`, `not:smart:4` and `:13`. It is expected
+that the last bare example be only used by the engine to add a global semaphore.
+
+### Graph definition file
 graph.yaml is the compiled graph definition file. The format is currently
 undocumented, but by looking through the [examples/](https://github.com/purpleidea/mgmt/tree/master/examples)
 you can probably figure out most of it, as it's fairly intuitive.
 
-###Command line
+### Command line
 The main interface to the `mgmt` tool is the command line. For the most recent
 documentation, please run `mgmt --help`.
 
-####`--yaml <graph.yaml>`
+#### `--yaml <graph.yaml>`
 Point to a graph file to run.
 
-####`--converged-timeout <seconds>`
+#### `--converged-timeout <seconds>`
 Exit if the machine has converged for approximately this many seconds.
 
-####`--max-runtime <seconds>`
+#### `--max-runtime <seconds>`
 Exit when the agent has run for approximately this many seconds. This is not
 generally recommended, but may be useful for users who know what they're doing.
 
-####`--noop`
+#### `--noop`
 Globally force all resources into no-op mode. This also disables the export to
 etcd functionality, but does not disable resource collection, however all
 resources that are collected will have their individual noop settings set.
 
-####`--remote <graph.yaml>`
+#### `--sema <size>`
+Globally add a counting semaphore of this size to each resource in the graph.
+The semaphore will get given an id of `:size`. In other words if you specify a
+size of 42, you can expect a semaphore if named: `:42`. It is expected that
+consumers of the semaphore metaparameter always include a prefix to avoid a
+collision with this globally defined semaphore. The size value must be greater
+than zero at this time. The traditional non-parallel execution found in config
+management tools such as `Puppet` can be obtained with `--sema 1`.
+
+#### `--remote <graph.yaml>`
 Point to a graph file to run on the remote host specified within. This parameter
 can be used multiple times if you'd like to remotely run on multiple hosts in
 parallel.
 
-####`--allow-interactive`
+#### `--allow-interactive`
 Allow interactive prompting for SSH passwords if there is no authentication
 method that works.
 
-####`--ssh-priv-id-rsa`
+#### `--ssh-priv-id-rsa`
 Specify the path for finding SSH keys. This defaults to `~/.ssh/id_rsa`. To
 never use this method of authentication, set this to the empty string.
 
-####`--cconns`
+#### `--cconns`
 The maximum number of concurrent remote ssh connections to run. This defaults
 to `0`, which means unlimited.
 
-####`--no-caching`
+#### `--no-caching`
 Don't allow remote caching of the remote execution binary. This will require
 the binary to be copied over for every remote execution, but it limits the
 likelihood that there is leftover information from the configuration process.
 
-####`--prefix <path>`
+#### `--prefix <path>`
 Specify a path to a custom working directory prefix. This directory will get
 created if it does not exist. This usually defaults to `/var/lib/mgmt/`. This
 can't be combined with the `--tmp-prefix` option. It can be combined with the
 `--allow-tmp-prefix` option.
 
-####`--tmp-prefix`
+#### `--tmp-prefix`
 If this option is specified, a temporary prefix will be used instead of the
 default prefix. This can't be combined with the `--prefix` option.
 
-####`--allow-tmp-prefix`
+#### `--allow-tmp-prefix`
 If this option is specified, we will attempt to fall back to a temporary prefix
 if the primary prefix couldn't be created. This is useful for avoiding failures
 in environments where the primary prefix may or may not be available, but you'd
@@ -513,7 +567,35 @@ like to try. The canonical example is when running `mgmt` with `--remote` there
 might be a cached copy of the binary in the primary prefix, but in case there's
 no binary available continue working in a temporary directory to avoid failure.
 
-##Examples
+### Compilation options
+
+You can control some compilation variables by using environment variables.
+
+#### Disable libvirt support
+
+If you wish to compile mgmt without libvirt, you can use the following command:
+
+```
+GOTAGS=novirt make build
+```
+
+#### Disable augeas support
+
+If you wish to compile mgmt without augeas support, you can use the following command:
+
+```
+GOTAGS=noaugeas make build
+```
+
+#### Combining compile-time flags
+
+You can combine multiple tags by using a space-separated list:
+
+```
+GOTAGS="noaugeas novirt" make build
+```
+
+## Examples
 For example configurations, please consult the [examples/](https://github.com/purpleidea/mgmt/tree/master/examples) directory in the git
 source repository. It is available from:
 
@@ -541,7 +623,7 @@ EOF
 sudo systemctl daemon-reload
 ```
 
-##Development
+## Development
 
 This is a project that I started in my free time in 2013. Development is driven
 by all of our collective patches! Dive right in, and start hacking!
@@ -551,9 +633,9 @@ You can follow along [on my technical blog](https://ttboj.wordpress.com/).
 
 To report any bugs, please file a ticket at: [https://github.com/purpleidea/mgmt/issues](https://github.com/purpleidea/mgmt/issues).
 
-##Authors
+## Authors
 
-Copyright (C) 2013-2016+ James Shubin and the project contributors
+Copyright (C) 2013-2017+ James Shubin and the project contributors
 
 Please see the
 [AUTHORS](https://github.com/purpleidea/mgmt/tree/master/AUTHORS) file

docs/index.rst

@@ -0,0 +1,17 @@
+.. mgmt documentation master file, created by
+   sphinx-quickstart on Wed Feb 15 21:34:09 2017.
+   You can adapt this file completely to your liking, but it should at least
+   contain the root `toctree` directive.
+
+Welcome to mgmt's documentation!
+================================
+
+.. toctree::
+   :maxdepth: 2
+   :caption: Contents:
+
+   documentation
+   quick-start-guide
+   resource-guide
+   prometheus
+   puppet-guide

docs/prometheus.md

@@ -0,0 +1,66 @@
+# Prometheus support
+
+Mgmt comes with a built-in prometheus support. It is disabled by default, and
+can be enabled with the `--prometheus` command line switch.
+
+By default, the prometheus instance will listen on [`127.0.0.1:9233`][pd]. You
+can change this setting by using the `--prometheus-listen` cli option:
+
+To have mgmt prometheus bind interface on 0.0.0.0:45001, use:
+`./mgmt r --prometheus --prometheus-listen :45001`
+
+## Metrics
+
+Mgmt exposes three kinds of resources: _go_ metrics, _etcd_ metrics and _mgmt_
+metrics.
+
+### go metrics
+
+We use the [prometheus go_collector][pgc] to expose go metrics. Those metrics
+are mainly useful for debugging and perf testing.
+
+### etcd metrics
+
+mgmt exposes etcd metrics. Read more in the [upstream documentation][etcdm]
+
+### mgmt metrics
+
+Here is a list of the metrics we provide:
+
+- `mgmt_resources_total`: The number of resources that mgmt is managing
+- `mgmt_checkapply_total`: The number of CheckApply's that mgmt has run
+- `mgmt_failures_total`: The number of resources that have failed
+- `mgmt_failures_current`: The number of resources that have failed
+- `mgmt_graph_start_time_seconds`: Start time of the current graph since unix epoch in seconds
+
+For each metric, you will get some extra labels:
+
+- `kind`: The kind of mgmt resource
+
+For `mgmt_checkapply_total`, those extra labels are set:
+
+- `eventful`: "true" or "false", if the CheckApply triggered some changes
+- `errorful`: "true" or "false", if the CheckApply reported an error
+- `apply`: "true" or "false", if the CheckApply ran in apply or noop mode
+
+## Alerting
+
+You can use prometheus to alert you upon changes or failures. We do not provide
+such templates yet, but we plan to provide some examples in this repository.
+Patches welcome!
+
+## Grafana
+
+We do not have grafana dashboards yet. Patches welcome!
+
+## External resources
+
+- [prometheus website](https://prometheus.io/)
+- [prometheus documentation](https://prometheus.io/docs/introduction/overview/)
+- [prometheus best practices regarding metrics
+  naming](https://prometheus.io/docs/practices/naming/)
+- [grafana website](http://grafana.org/)
+
+[pgc]: https://github.com/prometheus/client_golang/blob/master/prometheus/go_collector.go
+[etcdm]: https://coreos.com/etcd/docs/latest/metrics.html
+[pd]: https://github.com/prometheus/prometheus/wiki/Default-port-allocation

docs/puppet-guide.md

@@ -1,13 +1,4 @@
-#mgmt Puppet support
-
-1. [Prerequisites](#prerequisites)
-    * [Testing the Puppet side](#testing-the-puppet-side)
-2. [Writing a suitable manifest](#writing-a-suitable-manifest)
-    * [Unsupported attributes](#unsupported-attributes)
-    * [Unsupported resources](#unsupported-resources)
-    * [Avoiding common warnings](#avoiding-common-warnings)
-3. [Configuring Puppet](#configuring-puppet)
-4. [Caveats](#caveats)
+# Puppet guide
 
 `mgmt` can use Puppet as its source for the configuration graph.
 This document goes into detail on how this works, and lists
@@ -16,7 +7,7 @@ some pitfalls and limitations.
 For basic instructions on how to use the Puppet support, see
 the [main documentation](documentation.md#puppet-support).
 
-##Prerequisites
+## Prerequisites
 
 You need Puppet installed in your system. It is not important how you
 get it. On the most common Linux distributions, you can use packages
@@ -29,14 +20,16 @@ Any release of Puppet's 3.x and 4.x series should be suitable for use with
 `mgmt`. Most importantly, make sure to install the `ffrank-mgmtgraph` Puppet
 module (referred to below as "the translator module").
 
-    puppet module install ffrank-mgmtgraph
+```
+puppet module install ffrank-mgmtgraph
+```
 
 Please note that the module is not required on your Puppet master (if you
 use a master/agent setup). It's needed on the machine that runs `mgmt`.
 You can install the module on the master anyway, so that it gets distributed
 to your agents through Puppet's `pluginsync` mechanism.
 
-###Testing the Puppet side
+### Testing the Puppet side
 
 The following command should run successfully and print a YAML hash on your
 terminal:
@@ -48,9 +41,9 @@ puppet mgmtgraph print --code 'file { "/tmp/mgmt-test": ensure => present }'
 You can use this CLI to test any manifests before handing them straight
 to `mgmt`.
 
-##Writing a suitable manifest
+## Writing a suitable manifest
 
-###Unsupported attributes
+### Unsupported attributes
 
 `mgmt` inherited its resource module from Puppet, so by and large, it's quite
 possible to express `mgmt` graphs in terms of Puppet manifests. However,
@@ -62,8 +55,10 @@ For example, at the time of writing this, the `file` type in `mgmt` had no
 notion of permissions (the file `mode`) yet. This lead to the following
 warning (among others that will be discussed below):
 
-    $ puppet mgmtgraph print --code 'file { "/tmp/foo": mode => "0600" }'
-    Warning: cannot translate: File[/tmp/foo] { mode => "600" } (attribute is ignored)
+```
+$ puppet mgmtgraph print --code 'file { "/tmp/foo": mode => "0600" }'
+Warning: cannot translate: File[/tmp/foo] { mode => "600" } (attribute is ignored)
+```
 
 This is a heads-up for the user, because the resulting `mgmt` graph will
 in fact not pass this information to the `/tmp/foo` file resource, and
@@ -71,7 +66,7 @@ in fact not pass this information to the `/tmp/foo` file resource, and
 manifests that are written expressly for `mgmt` is not sensible and should
 be avoided.
 
-###Unsupported resources
+### Unsupported resources
 
 Puppet has a fairly large number of
 [built-in types](https://docs.puppet.com/puppet/latest/reference/type.html),
@@ -91,28 +86,32 @@ this overhead can amount to several orders of magnitude.
 
 Avoid Puppet types that `mgmt` does not implement (yet).
 
-###Avoiding common warnings
+### Avoiding common warnings
 
 Many resource parameters in Puppet take default values. For the most part,
 the translator module just ignores them. However, there are cases in which
 Puppet will default to convenient behavior that `mgmt` cannot quite replicate.
 For example, translating a plain `file` resource will lead to a warning message:
 
-    $ puppet mgmtgraph print --code 'file { "/tmp/mgmt-test": }'
-    Warning: File[/tmp/mgmt-test] uses the 'puppet' file bucket, which mgmt cannot do. There will be no backup copies!
+```
+$ puppet mgmtgraph print --code 'file { "/tmp/mgmt-test": }'
+Warning: File[/tmp/mgmt-test] uses the 'puppet' file bucket, which mgmt cannot do. There will be no backup copies!
+```
 
 The reason is that per default, Puppet assumes the following parameter value
 (among others)
 
 ```puppet
 file { "/tmp/mgmt-test":
-  backup => 'puppet',
+	backup => 'puppet',
 }
 ```
 
 To avoid this, specify the parameter explicitly:
 
-    $ puppet mgmtgraph print --code 'file { "/tmp/mgmt-test": backup => false }'
+```
+$ puppet mgmtgraph print --code 'file { "/tmp/mgmt-test": backup => false }'
+```
 
 This is tedious in a more complex manifest. A good simplification is the
 following [resource default](https://docs.puppet.com/puppet/latest/reference/lang_defaults.html)
@@ -125,7 +124,7 @@ File { backup => false }
 If you encounter similar warnings from other types and/or parameters,
 use the same approach to silence them if possible.
 
-##Configuring Puppet
+## Configuring Puppet
 
 Since `mgmt` uses an actual Puppet CLI behind the scenes, you might
 need to tweak some of Puppet's runtime options in order to make it
@@ -143,16 +142,20 @@ control all of them, through its `--puppet-conf` option. It allows
 you to specify which `puppet.conf` file should be used during
 translation.
 
-    mgmt run --puppet /opt/my-manifest.pp --puppet-conf /etc/mgmt/puppet.conf
+```
+mgmt run --puppet /opt/my-manifest.pp --puppet-conf /etc/mgmt/puppet.conf
+```
 
 Within this file, you can just specify any needed options in the
 `[main]` section:
 
-    [main]
-    server=mgmt-master.example.net
-    vardir=/var/lib/mgmt/puppet
+```
+[main]
+server=mgmt-master.example.net
+vardir=/var/lib/mgmt/puppet
+```
 
-##Caveats
+## Caveats
 
 Please see the [README](https://github.com/ffrank/puppet-mgmtgraph/blob/master/README.md)
 of the translator module for the current state of supported and unsupported

docs/quick-start-guide.md

@@ -0,0 +1,94 @@
+# Quick start guide
+
+## Introduction
+This guide is intended for developers. Once `mgmt` is minimally viable, we'll
+publish a quick start guide for users too. In the meantime, please contribute!
+If you're brand new to `mgmt`, it's probably a good idea to start by reading the
+[introductory article](https://ttboj.wordpress.com/2016/01/18/next-generation-configuration-mgmt/)
+or to watch an [introductory video](https://github.com/purpleidea/mgmt/#on-the-web).
+Once you're familiar with the general idea, please start hacking...
+
+## Vagrant
+If you would like to avoid doing the following steps manually, we have prepared
+a [Vagrant](https://www.vagrantup.com/) environment for your convenience. From
+the project directory, run a `vagrant up`, and then a `vagrant status`. From
+there, you can `vagrant ssh` into the `mgmt` machine. The MOTD will explain the
+rest.
+
+## Dependencies
+Software projects have a few different kinds of dependencies. There are _build_
+dependencies, _runtime_ dependencies, and additionally, a few extra dependencies
+required for running the _test_ suite.
+
+### Build
+* `golang` 1.8 or higher (required, available in some distros and distributed
+  as a binary officially by [golang.org](https://golang.org/dl/))
+* golang libraries (required, available with `go get ./...`) a partial list includes:
+```
+github.com/coreos/etcd/client
+gopkg.in/yaml.v2
+gopkg.in/fsnotify.v1
+github.com/urfave/cli
+github.com/coreos/go-systemd/dbus
+github.com/coreos/go-systemd/util
+github.com/libvirt/libvirt-go
+```
+* `stringer` (optional), available as a package on some platforms, otherwise via `go get`
+```
+golang.org/x/tools/cmd/stringer
+```
+* `pandoc` (optional), for building a pdf of the documentation
+
+### Runtime
+A relatively modern GNU/Linux system should be able to run `mgmt` without any
+problems. Since `mgmt` runs as a single statically compiled binary, all of the
+library dependencies are included. It is expected, that certain advanced
+resources require host specific facilities to work. These requirements are
+listed below:
+
+| Resource | Dependency        | Version |
+|----------|-------------------|---------|
+| file     | inotify           | ?       |
+| hostname | systemd-hostnamed | ?       |
+| nspawn   | systemd-nspawn    | ?       |
+| pkg      | packagekitd       | ?       |
+| svc      | systemd           | ?       |
+| virt     | libvirtd          | ?       |
+
+For building a visual representation of the graph, `graphviz` is required.
+
+### Testing
+* golint `github.com/golang/lint/golint`
+
+## Quick start
+* Make sure you have golang version 1.8 or greater installed.
+* If you do not have a GOPATH yet, create one and export it:
+```
+mkdir $HOME/gopath
+export GOPATH=$HOME/gopath
+```
+* You might also want to add the GOPATH to your `~/.bashrc` or `~/.profile`.
+* For more information you can read the [GOPATH documentation](https://golang.org/cmd/go/#hdr-GOPATH_environment_variable).
+* Next download the mgmt code base, and switch to that directory:
+```
+mkdir -p $GOPATH/src/github.com/purpleidea/
+cd $GOPATH/src/github.com/purpleidea/
+git clone --recursive https://github.com/purpleidea/mgmt/
+cd $GOPATH/src/github.com/purpleidea/mgmt
+```
+* Run `make deps` to install system and golang dependencies. Take a look at `misc/make-deps.sh` for details.
+* Run `make build` to get a freshly built `mgmt` binary.
+* Run `time ./mgmt run --yaml examples/graph0.yaml --converged-timeout=5 --tmp-prefix` to try out a very simple example!
+* To run continuously in the default mode of operation, omit the `--converged-timeout` option.
+* Have fun hacking on our future technology!
+
+## Examples
+Please look in the [examples/](../examples/) folder for some examples!
+
+## Installation
+Installation of `mgmt` from distribution packages currently needs improvement.
+At the moment we have:
+* [COPR](https://copr.fedoraproject.org/coprs/purpleidea/mgmt/)
+* [Arch](https://aur.archlinux.org/packages/mgmt/)
+
+Please contribute more! We'd especially like to see a Debian package!

docs/resource-guide.md

@@ -1,49 +1,6 @@
-#mgmt
+# Resource guide
 
-<!--
-Mgmt
-Copyright (C) 2013-2016+ James Shubin and the project contributors
-Written by James Shubin <james@shubin.ca> and the project contributors
-
-This program is free software: you can redistribute it and/or modify
-it under the terms of the GNU Affero General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-(at your option) any later version.
-
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU Affero General Public License for more details.
-
-You should have received a copy of the GNU Affero General Public License
-along with this program.  If not, see <http://www.gnu.org/licenses/>.
--->
-
-##mgmt resource guide by [James](https://ttboj.wordpress.com/)
-####Available from:
-####[https://github.com/purpleidea/mgmt/](https://github.com/purpleidea/mgmt/)
-
-####This documentation is available in: [Markdown](https://github.com/purpleidea/mgmt/blob/master/docs/resource-guide.md) or [PDF](https://pdfdoc-purpleidea.rhcloud.com/pdf/https://github.com/purpleidea/mgmt/blob/master/docs/resource-guide.md) format.
-
-####Table of Contents
-
-1. [Overview](#overview)
-2. [Theory - Resource theory in mgmt](#theory)
-3. [Resource API - Getting started with mgmt](#resource-api)
-	* [Init - Initialize the resource](#init)
-	* [CheckApply - Check and apply resource state](#checkapply)
-	* [Watch - Detect resource changes](#watch)
-	* [Compare - Compare resource with another](#compare)
-4. [Further considerations - More information about resource writing](#further-considerations)
-5. [Automatic edges - Adding automatic resources dependencies](#automatic-edges)
-6. [Automatic grouping - Grouping multiple resources into one](#automatic-grouping)
-7. [Send/Recv - Communication between resources](#send-recv)
-8. [Composite resources - Importing code from one resource into another](#composite-resources)
-9. [FAQ - Frequently asked questions](#frequently-asked-questions)
-10. [Suggestions - API change suggestions](#suggestions)
-11. [Authors - Authors and contact information](#authors)
-
-##Overview
+## Overview
 
 The `mgmt` tool has built-in resource primitives which make up the building
 blocks of any configuration. Each instance of a resource is mapped to a single
@@ -52,7 +9,7 @@ This guide is meant to instruct developers on how to write a brand new resource.
 Since `mgmt` and the core resources are written in golang, some prior golang
 knowledge is assumed.
 
-##Theory
+## Theory
 
 Resources in `mgmt` are similar to resources in other systems in that they are
 [idempotent](https://en.wikipedia.org/wiki/Idempotence). Our resources are
@@ -62,27 +19,67 @@ on this design, please read the
 [original article](https://ttboj.wordpress.com/2016/01/18/next-generation-configuration-mgmt/)
 on the subject.
 
-##Resource API
+## Resource API
 
 To implement a resource in `mgmt` it must satisfy the
 [`Res`](https://github.com/purpleidea/mgmt/blob/master/resources/resources.go)
 interface. What follows are each of the method signatures and a description of
 each.
 
-###Init
+### Default
+```golang
+Default() Res
+```
+
+This returns a populated resource struct as a `Res`. It shouldn't populate any
+values which already have the correct default as the golang zero value. In
+general it is preferable if the zero values make for the correct defaults.
+
+#### Example
+```golang
+// Default returns some sensible defaults for this resource.
+func (obj *FooRes) Default() Res {
+	return &FooRes{
+		Answer: 42, // sometimes, defaults shouldn't be the zero value
+	}
+}
+```
+
+### Validate
+```golang
+Validate() error
+```
+
+This method is used to validate if the populated resource struct is a valid
+representation of the resource kind. If it does not conform to the resource
+specifications, it should generate an error. If you notice that this method is
+quite large, it might be an indication that you should reconsider the parameter
+list and interface to this resource. This method is called _before_ `Init`.
+
+#### Example
+```golang
+// Validate reports any problems with the struct definition.
+func (obj *FooRes) Validate() error {
+	if obj.Answer != 42 { // validate whatever you want
+		return fmt.Errorf("expected an answer of 42")
+	}
+	return obj.BaseRes.Validate() // remember to call the base method!
+}
+```
+
+### Init
 ```golang
 Init() error
 ```
 
 This is called to initialize the resource. If something goes wrong, it should
-return an error. It should set the resource `kind`, do any resource specific
-work, and finish by calling the `Init` method of the base resource.
+return an error. It should do any resource specific work, and finish by calling
+the `Init` method of the base resource.
 
-####Example
+#### Example
 ```golang
 // Init initializes the Foo resource.
 func (obj *FooRes) Init() error {
-	obj.BaseRes.kind = "Foo" // must set capitalized resource kind
 	// run the resource specific initialization, and error if anything fails
 	if some_error {
 		return err // something went wrong!
@@ -91,7 +88,43 @@ func (obj *FooRes) Init() error {
 }
 ```
 
-###CheckApply
+This method is always called after `Validate` has run successfully, with the
+exception that we can't prevent a malicious or buggy `libmgmt` user to not run
+this. In other words, you should expect `Validate` to have run first, but you
+shouldn't allow `Init` to dangerously `rm -rf /$the_world` if your code only
+checks `$the_world` in `Validate`. Remember to always program safely!
+
+### Close
+```golang
+Close() error
+```
+
+This is called to cleanup after the resource. It is usually not necessary, but
+can be useful if you'd like to properly close a persistent connection that you
+opened in the `Init` method and were using throughout the resource.
+
+#### Example
+```golang
+// Close runs some cleanup code for this resource.
+func (obj *FooRes) Close() error {
+	err := obj.conn.Close() // close some internal connection
+
+	// call base close, b/c we're overriding
+	if e := obj.BaseRes.Close(); err == nil {
+		err = e
+	} else if e != nil {
+		err = multierr.Append(err, e) // list of errors
+	}
+	return err
+}
+```
+
+You should probably check the return errors of your internal methods, and pass
+on an error if something went wrong. Remember to always call the base `Close`
+method! If you plan to return early if you hit an internal error, then at least
+call it with a defer!
+
+### CheckApply
 ```golang
 CheckApply(apply bool) (checkOK bool, err error)
 ```
@@ -116,7 +149,7 @@ resource isn't now converged. This is not a bug, as the resources `Watch`
 facility will detect the change, ultimately resulting in a subsequent call to
 `CheckApply`.
 
-####Example
+#### Example
 ```golang
 // CheckApply does the idempotent work of checking and applying resource state.
 func (obj *FooRes) CheckApply(apply bool) (bool, error) {
@@ -137,7 +170,7 @@ skipped. This is an engine optimization, and not a bug. It is mentioned here in
 the documentation in case you are confused as to why a debug message you've
 added to the code isn't always printed.
 
-####Refresh notifications
+#### Refresh notifications
 Some resources may choose to support receiving refresh notifications. In general
 these should be avoided if possible, but nevertheless, they do make sense in
 certain situations. Resources that support these need to verify if one was sent
@@ -150,7 +183,7 @@ action is applied by that resource and are transmitted through graph edges which
 have enabled their propagation. Resources that currently perform some refresh
 action include `svc`, `timer`, and `password`.
 
-####Paired execution
+#### Paired execution
 For many resources it is not uncommon to see `CheckApply` run twice in rapid
 succession. This is usually not a pathological occurrence, but rather a healthy
 pattern which is a consequence of the event system. When the state of the
@@ -159,21 +192,21 @@ having just changed the state, it is usually the case that this repair will
 trigger the `Watch` code! In response, a second `CheckApply` is triggered, which
 will likely find the state to now be correct.
 
-####Summary
+#### Summary
 * Anytime an error occurs during `CheckApply`, you should return `(false, err)`.
 * If the state is correct and no changes are needed, return `(true, nil)`.
 * You should only make changes to the system if `apply` is set to `true`.
 * After checking the state and possibly applying the fix, return `(false, nil)`.
 * Returning `(true, err)` is a programming error and will cause a `Fatal`.
 
-###Watch
+### Watch
 ```golang
-Watch(chan Event) error
+Watch() error
 ```
 
 `Watch` is a main loop that runs and sends messages when it detects that the
 state of the resource might have changed. To send a message you should write to
-the input `Event` channel using the `DoSend` helper method. The Watch function
+the input event channel using the `Event` helper method. The Watch function
 should run continuously until a shutdown message is received. If at any time
 something goes wrong, you should return an error, and the `mgmt` engine will
 handle possibly restarting the main loop based on the `retry` meta parameters.
@@ -195,36 +228,35 @@ If the resource is activated in `polling` mode, the `Watch` method will not get
 executed. As a result, the resource must still work even if the main loop is not
 running.
 
-####Select
+#### Select
 The lifetime of most resources `Watch` method should be spent in an infinite
 loop that is bounded by a `select` call. The `select` call is the point where
 our method hands back control to the engine (and the kernel) so that we can
 sleep until something of interest wakes us up. In this loop we must process
-events from the engine via the `<-obj.Events()` call, wait for the converged
-timeout with `<-cuid.ConvergedTimer()`, and receive events for our resource
-itself!
+events from the engine via the `<-obj.Events()` call, and receive events for our
+resource itself!
 
-####Events
+#### Events
 If we receive an internal event from the `<-obj.Events()` method, we can read it
 with the ReadEvent helper function. This function tells us if we should shutdown
 our resource, and if we should generate an event. When we want to send an event,
-we use the `DoSend` helper function. It is also important to mark the resource
+we use the `Event` helper function. It is also important to mark the resource
 state as `dirty` if we believe it might have changed. We do this with the
 `StateOK(false)` function.
 
-####Startup
+#### Startup
 Once the `Watch` function has finished starting up successfully, it is important
 to generate one event to notify the `mgmt` engine that we're now listening
 successfully, so that it can run an initial `CheckApply` to ensure we're safely
 tracking a healthy state and that we didn't miss anything when `Watch` was down
 or from before `mgmt` was running. It does this by calling the `Running` method.
 
-####Converged
+#### Converged
 The engine might be asked to shutdown when the entire state of the system has
-not seen any changes for some duration of time. In order for the engine to be
-able to make this determination, each resource must report its converged state.
+not seen any changes for some duration of time. The engine can determine this
+automatically, but each resource can block this if it is absolutely necessary.
 To do this, the `Watch` method should get the `ConvergedUID` handle that has
-been prepared for it by the engine. This is done by calling the `Converger`
+been prepared for it by the engine. This is done by calling the `ConvergerUID`
 method on the resource object. The result can be used to set the converged
 status with `SetConverged`, and to notify when the particular timeout has been
 reached by waiting on `ConvergedTimer`.
@@ -233,12 +265,14 @@ Instead of interacting with the `ConvergedUID` with these two methods, we can
 instead use the `StartTimer` and `ResetTimer` methods which accomplish the same
 thing, but provide a `select`-free interface for different coding situations.
 
-####Example
+This particular facility is most likely not required for most resources. It may
+prove to be useful if a resource wants to start off a long operation, but avoid
+sending out erroneous `Event` messages to keep things alive until it finishes.
+
+#### Example
 ```golang
 // Watch is the listener and main loop for this resource.
-func (obj *FooRes) Watch(processChan chan event.Event) error {
-	cuid := obj.Converger() // get the converger uid used to report status
-
+func (obj *FooRes) Watch() error {
 	// setup the Foo resource
 	var err error
 	if err, obj.foo = OpenFoo(); err != nil {
@@ -247,59 +281,49 @@ func (obj *FooRes) Watch(processChan chan event.Event) error {
 	defer obj.whatever.CloseFoo() // shutdown our
 
 	// notify engine that we're running
-	if err := obj.Running(processChan); err != nil {
+	if err := obj.Running(); err != nil {
 		return err // bubble up a NACK...
 	}
 
 	var send = false // send event?
-	var exit = false
+	var exit *error
 	for {
-		obj.SetState(ResStateWatching) // reset
 		select {
 		case event := <-obj.Events():
-			cuid.SetConverged(false)
 			// we avoid sending events on unpause
-			if exit, send = obj.ReadEvent(&event); exit {
-				return nil // exit
+			if exit, send = obj.ReadEvent(event); exit != nil {
+				return *exit // exit
 			}
 
 		// the actual events!
 		case event := <-obj.foo.Events:
 			if is_an_event {
 				send = true // used below
-				cuid.SetConverged(false)
 				obj.StateOK(false) // dirty
 			}
 
 		// event errors
 		case err := <-obj.foo.Errors:
-			cuuid.SetConverged(false)
 			return err // will cause a retry or permanent failure
-
-		case <-cuid.ConvergedTimer():
-			cuid.SetConverged(true) // converged!
-			continue
 		}
 
 		// do all our event sending all together to avoid duplicate msgs
 		if send {
 			send = false
-			if exit, err := obj.DoSend(processChan, ""); exit || err != nil {
-				return err // we exit or bubble up a NACK...
-			}
+			obj.Event() // send the event!
 		}
 	}
 }
 ```
 
-####Summary
+#### Summary
 * Remember to call the appropriate `converger` methods throughout the resource.
 * Remember to call `Startup` when the `Watch` is running successfully.
 * Remember to process internal events and shutdown promptly if asked to.
 * Ensure the design of your resource is well thought out.
 * Have a look at the existing resources for a rough idea of how this all works.
 
-###Compare
+### Compare
 ```golang
 Compare(Res) bool
 ```
@@ -316,80 +340,106 @@ need to be changed. On occasion, not all of them need to be compared, in
 particular if they store some generated state, or if they aren't significant in
 some way.
 
-####Example
+#### Example
 ```golang
 // Compare two resources and return if they are equivalent.
-func (obj *FooRes) Compare(res Res) bool {
-	switch res.(type) {
-	case *FooRes: // only compare to other resources of the Foo kind!
-		res := res.(*FileRes)
-		if !obj.BaseRes.Compare(res) { // call base Compare
-			return false
-		}
-		if obj.Name != res.Name {
-			return false
-		}
-		if obj.whatever != res.whatever {
-			return false
-		}
-		if obj.Flag != res.Flag {
-			return false
-		}
-	default:
-		return false // different kind of resource
+func (obj *FooRes) Compare(r Res) bool {
+	// we can only compare FooRes to others of the same resource kind
+	res, ok := r.(*FooRes)
+	if !ok {
+		return false
 	}
+	if !obj.BaseRes.Compare(res) { // call base Compare
+		return false
+	}
+	if obj.Name != res.Name {
+		return false
+	}
+
+	if obj.whatever != res.whatever {
+		return false
+	}
+	if obj.Flag != res.Flag {
+		return false
+	}
+
 	return true // they must match!
 }
 ```
 
-###Validate
+### UIDs
 ```golang
-Validate() error
+UIDs() []ResUID
 ```
 
-This method is used to validate if the populated resource struct is a valid
-representation of the resource kind. If it does not conform to the resource
-specifications, it should generate an error. If you notice that this method is
-quite large, it might be an indication that you might want to reconsider the
-parameter list and interface to this resource.
-
-###GetUIDs
-```golang
-GetUIDs() []ResUID
-```
-
-The `GetUIDs` method returns a list of `ResUID` interfaces that represent the
+The `UIDs` method returns a list of `ResUID` interfaces that represent the
 particular resource uniquely. This is used with the AutoEdges API to determine
 if another resource can match a dependency to this one.
 
-###AutoEdges
+### AutoEdges
 ```golang
-AutoEdges() AutoEdge
+AutoEdges() (AutoEdge, error)
 ```
 
 This returns a struct that implements the `AutoEdge` interface. This struct
 is used to match other resources that might be relevant dependencies for this
 resource.
 
-###CollectPattern
+### CollectPattern
 ```golang
 CollectPattern() string
 ```
 
 This is currently a stub and will be updated once the DSL is further along.
 
-##Further considerations
+### UnmarshalYAML
+```golang
+UnmarshalYAML(unmarshal func(interface{}) error) error // optional
+```
+
+This is optional, but recommended for any resource that will have a YAML
+accessible struct. It is not required because to do so would mean that
+third-party or custom resources (such as those someone writes to use with
+`libmgmt`) would have to implement this needlessly.
+
+The signature intentionally matches what is required to satisfy the `go-yaml`
+[Unmarshaler](https://godoc.org/gopkg.in/yaml.v2#Unmarshaler) interface.
+
+#### Example
+```golang
+// UnmarshalYAML is the custom unmarshal handler for this struct.
+// It is primarily useful for setting the defaults.
+func (obj *FooRes) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	type rawRes FooRes // indirection to avoid infinite recursion
+
+	def := obj.Default()     // get the default
+	res, ok := def.(*FooRes) // put in the right format
+	if !ok {
+		return fmt.Errorf("could not convert to FooRes")
+	}
+	raw := rawRes(*res) // convert; the defaults go here
+
+	if err := unmarshal(&raw); err != nil {
+		return err
+	}
+
+	*obj = FooRes(raw) // restore from indirection with type conversion!
+	return nil
+}
+```
+
+## Further considerations
 There is some additional information that any resource writer will need to know.
 Each issue is listed separately below!
 
-###Resource struct
+### Resource struct
 Each resource will implement methods as pointer receivers on a resource struct.
 The resource struct must include an anonymous reference to the `BaseRes` struct.
 The naming convention for resources is that they end with a `Res` suffix. If
 you'd like your resource to be accessible by the `YAML` graph API (GAPI), then
 you'll need to include the appropriate YAML fields as shown below.
 
-####Example
+#### Example
 ```golang
 type FooRes struct {
 	BaseRes `yaml:",inline"` // base properties
@@ -402,43 +452,26 @@ type FooRes struct {
 }
 ```
 
-###YAML
-In addition to labelling your resource struct with YAML fields, you must also
-add an entry to the internal `GraphConfig` struct. It is a fairly straight
-forward one line patch.
+### Resource registration
+All resources must be registered with the engine so that they can be found. This
+also ensures they can be encoded and decoded. Make sure to include the following
+code snippet for this to work.
 
 ```golang
-type GraphConfig struct {
-// [snip...]
-	Resources struct {
-		Noop []*resources.NoopRes `yaml:"noop"`
-		File []*resources.FileRes `yaml:"file"`
-		// [snip...]
-		Foo []*resources.FooRes `yaml:"foo"` // tada :)
-	}
-}
-```
-
-###Gob registration
-All resources must be registered with the `golang` _gob_ module so that they can
-be encoded and decoded. Make sure to include the following code snippet for this
-to work.
-
-```golang
-import "encoding/gob"
 func init() { // special golang method that runs once
-	gob.Register(&FooRes{}) // substitude your resource here
+	// set your resource kind and struct here (the kind must be lower case)
+	RegisterResource("foo", func() Res { return &FooRes{} })
 }
 ```
 
-##Automatic edges
+## Automatic edges
 Automatic edges in `mgmt` are well described in [this article](https://ttboj.wordpress.com/2016/03/14/automatic-edges-in-mgmt/).
 The best example of this technique can be seen in the `svc` resource.
 Unfortunately no further documentation about this subject has been written. To
 expand this section, please send a patch! Please contact us if you'd like to
 work on a resource that uses this feature, or to add it to an existing one!
 
-##Automatic grouping
+## Automatic grouping
 Automatic grouping in `mgmt` is well described in [this article](https://ttboj.wordpress.com/2016/03/30/automatic-grouping-in-mgmt/).
 The best example of this technique can be seen in the `pkg` resource.
 Unfortunately no further documentation about this subject has been written. To
@@ -446,7 +479,7 @@ expand this section, please send a patch! Please contact us if you'd like to
 work on a resource that uses this feature, or to add it to an existing one!
 
 
-##Send/Recv
+## Send/Recv
 In `mgmt` there is a novel concept called _Send/Recv_. For some background,
 please [read the introductory article](https://ttboj.wordpress.com/2016/12/07/sendrecv-in-mgmt/).
 When using this feature, the engine will automatically send the user specified
@@ -463,7 +496,7 @@ This can _only_ be done inside of the `CheckApply` function!
 ```golang
 // inside CheckApply, probably near the top
 if val, exists := obj.Recv["SomeKey"]; exists {
-	log.Printf("SomeKey was sent to us from: %s[%s].%s", val.Res.Kind(), val.Res.GetName(), val.Key)
+	log.Printf("SomeKey was sent to us from: %s.%s", val.Res, val.Key)
 	if val.Changed {
 		log.Printf("SomeKey was just updated!")
 		// you may want to invalidate some local cache
@@ -489,7 +522,7 @@ such as for cache invalidation.
 
 Remember, `Send/Recv` only changes your resource code if you cache state.
 
-##Composite resources
+## Composite resources
 Composite resources are resources which embed one or more existing resources.
 This is useful to prevent code duplication in higher level resource scenarios.
 The best example of this technique can be seen in the `nspawn` resource which
@@ -498,37 +531,25 @@ Unfortunately no further documentation about this subject has been written. To
 expand this section, please send a patch! Please contact us if you'd like to
 work on a resource that uses this feature, or to add it to an existing one!
 
-##Frequently asked questions
+## Frequently asked questions
 (Send your questions as a patch to this FAQ! I'll review it, merge it, and
 respond by commit with the answer.)
 
-###Can I write resources in a different language?
+### Can I write resources in a different language?
 Currently `golang` is the only supported language for built-in resources. We
 might consider allowing external resources to be imported in the future. This
 will likely require a language that can expose a C-like API, such as `python` or
 `ruby`. Custom `golang` resources are already possible when using mgmt as a lib.
 Higher level resource collections will be possible once the `mgmt` DSL is ready.
 
-###What new resource primitives need writing?
+### What new resource primitives need writing?
 There are still many ideas for new resources that haven't been written yet. If
 you'd like to contribute one, please contact us and tell us about your idea!
 
-###Where can I find more information about mgmt?
+### Where can I find more information about mgmt?
 Additional blog posts, videos and other material [is available!](https://github.com/purpleidea/mgmt/#on-the-web).
 
-##Suggestions
+## Suggestions
 If you have any ideas for API changes or other improvements to resource writing,
 please let us know! We're still pre 1.0 and pre 0.1 and happy to break API in
 order to get it right!
-
-##Authors
-
-Copyright (C) 2013-2016+ James Shubin and the project contributors
-
-Please see the
-[AUTHORS](https://github.com/purpleidea/mgmt/tree/master/AUTHORS) file
-for more information.
-
-* [github](https://github.com/purpleidea/)
-* [&#64;purpleidea](https://twitter.com/#!/purpleidea)
-* [https://ttboj.wordpress.com/](https://ttboj.wordpress.com/)

etcd/methods.go

@@ -0,0 +1,412 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package etcd
+
+import (
+	"fmt"
+	"log"
+	"strconv"
+	"strings"
+
+	etcd "github.com/coreos/etcd/clientv3"
+	rpctypes "github.com/coreos/etcd/etcdserver/api/v3rpc/rpctypes"
+	etcdtypes "github.com/coreos/etcd/pkg/types"
+	context "golang.org/x/net/context"
+)
+
+// TODO: Could all these Etcd*(obj *EmbdEtcd, ...) functions which deal with the
+// interface between etcd paths and behaviour be grouped into a single struct ?
+
+// Nominate nominates a particular client to be a server (peer).
+func Nominate(obj *EmbdEtcd, hostname string, urls etcdtypes.URLs) error {
+	if obj.flags.Trace {
+		log.Printf("Trace: Etcd: Nominate(%v): %v", hostname, urls.String())
+		defer log.Printf("Trace: Etcd: Nominate(%v): Finished!", hostname)
+	}
+	// nominate someone to be a server
+	nominate := fmt.Sprintf("/%s/nominated/%s", NS, hostname)
+	ops := []etcd.Op{} // list of ops in this txn
+	if urls != nil {
+		ops = append(ops, etcd.OpPut(nominate, urls.String())) // TODO: add a TTL? (etcd.WithLease)
+
+	} else { // delete message if set to erase
+		ops = append(ops, etcd.OpDelete(nominate))
+	}
+
+	if _, err := obj.Txn(nil, ops, nil); err != nil {
+		return fmt.Errorf("nominate failed") // exit in progress?
+	}
+	return nil
+}
+
+// Nominated returns a urls map of nominated etcd server volunteers.
+// NOTE: I know 'nominees' might be more correct, but is less consistent here
+func Nominated(obj *EmbdEtcd) (etcdtypes.URLsMap, error) {
+	path := fmt.Sprintf("/%s/nominated/", NS)
+	keyMap, err := obj.Get(path, etcd.WithPrefix()) // map[string]string, bool
+	if err != nil {
+		return nil, fmt.Errorf("nominated isn't available: %v", err)
+	}
+	nominated := make(etcdtypes.URLsMap)
+	for key, val := range keyMap { // loop through directory of nominated
+		if !strings.HasPrefix(key, path) {
+			continue
+		}
+		name := key[len(path):] // get name of nominee
+		if val == "" {          // skip "erased" values
+			continue
+		}
+		urls, err := etcdtypes.NewURLs(strings.Split(val, ","))
+		if err != nil {
+			return nil, fmt.Errorf("nominated data format error: %v", err)
+		}
+		nominated[name] = urls // add to map
+		if obj.flags.Debug {
+			log.Printf("Etcd: Nominated(%v): %v", name, val)
+		}
+	}
+	return nominated, nil
+}
+
+// Volunteer offers yourself up to be a server if needed.
+func Volunteer(obj *EmbdEtcd, urls etcdtypes.URLs) error {
+	if obj.flags.Trace {
+		log.Printf("Trace: Etcd: Volunteer(%v): %v", obj.hostname, urls.String())
+		defer log.Printf("Trace: Etcd: Volunteer(%v): Finished!", obj.hostname)
+	}
+	// volunteer to be a server
+	volunteer := fmt.Sprintf("/%s/volunteers/%s", NS, obj.hostname)
+	ops := []etcd.Op{} // list of ops in this txn
+	if urls != nil {
+		// XXX: adding a TTL is crucial! (i think)
+		ops = append(ops, etcd.OpPut(volunteer, urls.String())) // value is usually a peer "serverURL"
+
+	} else { // delete message if set to erase
+		ops = append(ops, etcd.OpDelete(volunteer))
+	}
+
+	if _, err := obj.Txn(nil, ops, nil); err != nil {
+		return fmt.Errorf("volunteering failed") // exit in progress?
+	}
+	return nil
+}
+
+// Volunteers returns a urls map of available etcd server volunteers.
+func Volunteers(obj *EmbdEtcd) (etcdtypes.URLsMap, error) {
+	if obj.flags.Trace {
+		log.Printf("Trace: Etcd: Volunteers()")
+		defer log.Printf("Trace: Etcd: Volunteers(): Finished!")
+	}
+	path := fmt.Sprintf("/%s/volunteers/", NS)
+	keyMap, err := obj.Get(path, etcd.WithPrefix())
+	if err != nil {
+		return nil, fmt.Errorf("volunteers aren't available: %v", err)
+	}
+	volunteers := make(etcdtypes.URLsMap)
+	for key, val := range keyMap { // loop through directory of volunteers
+		if !strings.HasPrefix(key, path) {
+			continue
+		}
+		name := key[len(path):] // get name of volunteer
+		if val == "" {          // skip "erased" values
+			continue
+		}
+		urls, err := etcdtypes.NewURLs(strings.Split(val, ","))
+		if err != nil {
+			return nil, fmt.Errorf("volunteers data format error: %v", err)
+		}
+		volunteers[name] = urls // add to map
+		if obj.flags.Debug {
+			log.Printf("Etcd: Volunteer(%v): %v", name, val)
+		}
+	}
+	return volunteers, nil
+}
+
+// AdvertiseEndpoints advertises the list of available client endpoints.
+func AdvertiseEndpoints(obj *EmbdEtcd, urls etcdtypes.URLs) error {
+	if obj.flags.Trace {
+		log.Printf("Trace: Etcd: AdvertiseEndpoints(%v): %v", obj.hostname, urls.String())
+		defer log.Printf("Trace: Etcd: AdvertiseEndpoints(%v): Finished!", obj.hostname)
+	}
+	// advertise endpoints
+	endpoints := fmt.Sprintf("/%s/endpoints/%s", NS, obj.hostname)
+	ops := []etcd.Op{} // list of ops in this txn
+	if urls != nil {
+		// TODO: add a TTL? (etcd.WithLease)
+		ops = append(ops, etcd.OpPut(endpoints, urls.String())) // value is usually a "clientURL"
+
+	} else { // delete message if set to erase
+		ops = append(ops, etcd.OpDelete(endpoints))
+	}
+
+	if _, err := obj.Txn(nil, ops, nil); err != nil {
+		return fmt.Errorf("endpoint advertising failed") // exit in progress?
+	}
+	return nil
+}
+
+// Endpoints returns a urls map of available etcd server endpoints.
+func Endpoints(obj *EmbdEtcd) (etcdtypes.URLsMap, error) {
+	if obj.flags.Trace {
+		log.Printf("Trace: Etcd: Endpoints()")
+		defer log.Printf("Trace: Etcd: Endpoints(): Finished!")
+	}
+	path := fmt.Sprintf("/%s/endpoints/", NS)
+	keyMap, err := obj.Get(path, etcd.WithPrefix())
+	if err != nil {
+		return nil, fmt.Errorf("endpoints aren't available: %v", err)
+	}
+	endpoints := make(etcdtypes.URLsMap)
+	for key, val := range keyMap { // loop through directory of endpoints
+		if !strings.HasPrefix(key, path) {
+			continue
+		}
+		name := key[len(path):] // get name of volunteer
+		if val == "" {          // skip "erased" values
+			continue
+		}
+		urls, err := etcdtypes.NewURLs(strings.Split(val, ","))
+		if err != nil {
+			return nil, fmt.Errorf("endpoints data format error: %v", err)
+		}
+		endpoints[name] = urls // add to map
+		if obj.flags.Debug {
+			log.Printf("Etcd: Endpoint(%v): %v", name, val)
+		}
+	}
+	return endpoints, nil
+}
+
+// SetHostnameConverged sets whether a specific hostname is converged.
+func SetHostnameConverged(obj *EmbdEtcd, hostname string, isConverged bool) error {
+	if obj.flags.Trace {
+		log.Printf("Trace: Etcd: SetHostnameConverged(%s): %v", hostname, isConverged)
+		defer log.Printf("Trace: Etcd: SetHostnameConverged(%v): Finished!", hostname)
+	}
+	converged := fmt.Sprintf("/%s/converged/%s", NS, hostname)
+	op := []etcd.Op{etcd.OpPut(converged, fmt.Sprintf("%t", isConverged))}
+	if _, err := obj.Txn(nil, op, nil); err != nil { // TODO: do we need a skipConv flag here too?
+		return fmt.Errorf("set converged failed") // exit in progress?
+	}
+	return nil
+}
+
+// HostnameConverged returns a map of every hostname's converged state.
+func HostnameConverged(obj *EmbdEtcd) (map[string]bool, error) {
+	if obj.flags.Trace {
+		log.Printf("Trace: Etcd: HostnameConverged()")
+		defer log.Printf("Trace: Etcd: HostnameConverged(): Finished!")
+	}
+	path := fmt.Sprintf("/%s/converged/", NS)
+	keyMap, err := obj.ComplexGet(path, true, etcd.WithPrefix()) // don't un-converge
+	if err != nil {
+		return nil, fmt.Errorf("converged values aren't available: %v", err)
+	}
+	converged := make(map[string]bool)
+	for key, val := range keyMap { // loop through directory...
+		if !strings.HasPrefix(key, path) {
+			continue
+		}
+		name := key[len(path):] // get name of key
+		if val == "" {          // skip "erased" values
+			continue
+		}
+		b, err := strconv.ParseBool(val)
+		if err != nil {
+			return nil, fmt.Errorf("converged data format error: %v", err)
+		}
+		converged[name] = b // add to map
+	}
+	return converged, nil
+}
+
+// AddHostnameConvergedWatcher adds a watcher with a callback that runs on
+// hostname state changes.
+func AddHostnameConvergedWatcher(obj *EmbdEtcd, callbackFn func(map[string]bool) error) (func(), error) {
+	path := fmt.Sprintf("/%s/converged/", NS)
+	internalCbFn := func(re *RE) error {
+		// TODO: get the value from the response, and apply delta...
+		// for now, just run a get operation which is easier to code!
+		m, err := HostnameConverged(obj)
+		if err != nil {
+			return err
+		}
+		return callbackFn(m) // call my function
+	}
+	return obj.AddWatcher(path, internalCbFn, true, true, etcd.WithPrefix()) // no block and no converger reset
+}
+
+// SetClusterSize sets the ideal target cluster size of etcd peers.
+func SetClusterSize(obj *EmbdEtcd, value uint16) error {
+	if obj.flags.Trace {
+		log.Printf("Trace: Etcd: SetClusterSize(): %v", value)
+		defer log.Printf("Trace: Etcd: SetClusterSize(): Finished!")
+	}
+	key := fmt.Sprintf("/%s/idealClusterSize", NS)
+
+	if err := obj.Set(key, strconv.FormatUint(uint64(value), 10)); err != nil {
+		return fmt.Errorf("function SetClusterSize failed: %v", err) // exit in progress?
+	}
+	return nil
+}
+
+// GetClusterSize gets the ideal target cluster size of etcd peers.
+func GetClusterSize(obj *EmbdEtcd) (uint16, error) {
+	key := fmt.Sprintf("/%s/idealClusterSize", NS)
+	keyMap, err := obj.Get(key)
+	if err != nil {
+		return 0, fmt.Errorf("function GetClusterSize failed: %v", err)
+	}
+
+	val, exists := keyMap[key]
+	if !exists || val == "" {
+		return 0, fmt.Errorf("function GetClusterSize failed: %v", err)
+	}
+
+	v, err := strconv.ParseUint(val, 10, 16)
+	if err != nil {
+		return 0, fmt.Errorf("function GetClusterSize failed: %v", err)
+	}
+	return uint16(v), nil
+}
+
+// MemberAdd adds a member to the cluster.
+func MemberAdd(obj *EmbdEtcd, peerURLs etcdtypes.URLs) (*etcd.MemberAddResponse, error) {
+	//obj.Connect(false) // TODO: ?
+	ctx := context.Background()
+	var response *etcd.MemberAddResponse
+	var err error
+	for {
+		if obj.exiting { // the exit signal has been sent!
+			return nil, fmt.Errorf("exiting etcd")
+		}
+		obj.rLock.RLock()
+		response, err = obj.client.MemberAdd(ctx, peerURLs.StringSlice())
+		obj.rLock.RUnlock()
+		if err == nil {
+			break
+		}
+		if ctx, err = obj.CtxError(ctx, err); err != nil {
+			return nil, err
+		}
+	}
+	return response, nil
+}
+
+// MemberRemove removes a member by mID and returns if it worked, and also
+// if there was an error. This is because it might have run without error, but
+// the member wasn't found, for example.
+func MemberRemove(obj *EmbdEtcd, mID uint64) (bool, error) {
+	//obj.Connect(false) // TODO: ?
+	ctx := context.Background()
+	for {
+		if obj.exiting { // the exit signal has been sent!
+			return false, fmt.Errorf("exiting etcd")
+		}
+		obj.rLock.RLock()
+		_, err := obj.client.MemberRemove(ctx, mID)
+		obj.rLock.RUnlock()
+		if err == nil {
+			break
+		} else if err == rpctypes.ErrMemberNotFound {
+			// if we get this, member already shut itself down :)
+			return false, nil
+		}
+		if ctx, err = obj.CtxError(ctx, err); err != nil {
+			return false, err
+		}
+	}
+	return true, nil
+}
+
+// Members returns information on cluster membership.
+// The member ID's are the keys, because an empty names means unstarted!
+// TODO: consider queueing this through the main loop with CtxError(ctx, err)
+func Members(obj *EmbdEtcd) (map[uint64]string, error) {
+	//obj.Connect(false) // TODO: ?
+	ctx := context.Background()
+	var response *etcd.MemberListResponse
+	var err error
+	for {
+		if obj.exiting { // the exit signal has been sent!
+			return nil, fmt.Errorf("exiting etcd")
+		}
+		obj.rLock.RLock()
+		if obj.flags.Trace {
+			log.Printf("Trace: Etcd: Members(): Endpoints are: %v", obj.client.Endpoints())
+		}
+		response, err = obj.client.MemberList(ctx)
+		obj.rLock.RUnlock()
+		if err == nil {
+			break
+		}
+		if ctx, err = obj.CtxError(ctx, err); err != nil {
+			return nil, err
+		}
+	}
+
+	members := make(map[uint64]string)
+	for _, x := range response.Members {
+		members[x.ID] = x.Name // x.Name will be "" if unstarted!
+	}
+	return members, nil
+}
+
+// Leader returns the current leader of the etcd server cluster.
+func Leader(obj *EmbdEtcd) (string, error) {
+	//obj.Connect(false) // TODO: ?
+	var err error
+	membersMap := make(map[uint64]string)
+	if membersMap, err = Members(obj); err != nil {
+		return "", err
+	}
+	addresses := obj.LocalhostClientURLs() // heuristic, but probably correct
+	if len(addresses) == 0 {
+		// probably a programming error...
+		return "", fmt.Errorf("programming error")
+	}
+	endpoint := addresses[0].Host // FIXME: arbitrarily picked the first one
+
+	// part two
+	ctx := context.Background()
+	var response *etcd.StatusResponse
+	for {
+		if obj.exiting { // the exit signal has been sent!
+			return "", fmt.Errorf("exiting etcd")
+		}
+
+		obj.rLock.RLock()
+		response, err = obj.client.Maintenance.Status(ctx, endpoint)
+		obj.rLock.RUnlock()
+		if err == nil {
+			break
+		}
+		if ctx, err = obj.CtxError(ctx, err); err != nil {
+			return "", err
+		}
+	}
+
+	// isLeader: response.Header.MemberId == response.Leader
+	for id, name := range membersMap {
+		if id == response.Leader {
+			return name, nil
+		}
+	}
+	return "", fmt.Errorf("members map is not current") // not found
+}

etcd/resources.go

@@ -0,0 +1,181 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package etcd
+
+import (
+	"fmt"
+	"log"
+	"strings"
+
+	"github.com/purpleidea/mgmt/resources"
+	"github.com/purpleidea/mgmt/util"
+
+	etcd "github.com/coreos/etcd/clientv3"
+)
+
+// WatchResources returns a channel that outputs events when exported resources
+// change.
+// TODO: Filter our watch (on the server side if possible) based on the
+// collection prefixes and filters that we care about...
+func WatchResources(obj *EmbdEtcd) chan error {
+	ch := make(chan error, 1) // buffer it so we can measure it
+	path := fmt.Sprintf("/%s/exported/", NS)
+	callback := func(re *RE) error {
+		// TODO: is this even needed? it used to happen on conn errors
+		log.Printf("Etcd: Watch: Path: %v", path) // event
+		if re == nil || re.response.Canceled {
+			return fmt.Errorf("watch is empty") // will cause a CtxError+retry
+		}
+		// we normally need to check if anything changed since the last
+		// event, since a set (export) with no changes still causes the
+		// watcher to trigger and this would cause an infinite loop. we
+		// don't need to do this check anymore because we do the export
+		// transactionally, and only if a change is needed. since it is
+		// atomic, all the changes arrive together which avoids dupes!!
+		if len(ch) == 0 { // send event only if one isn't pending
+			// this check avoids multiple events all queueing up and then
+			// being released continuously long after the changes stopped
+			// do not block!
+			ch <- nil // event
+		}
+		return nil
+	}
+	_, _ = obj.AddWatcher(path, callback, true, false, etcd.WithPrefix()) // no need to check errors
+	return ch
+}
+
+// SetResources exports all of the resources which we pass in to etcd.
+func SetResources(obj *EmbdEtcd, hostname string, resourceList []resources.Res) error {
+	// key structure is /$NS/exported/$hostname/resources/$uid = $data
+
+	var kindFilter []string // empty to get from everyone
+	hostnameFilter := []string{hostname}
+	// this is not a race because we should only be reading keys which we
+	// set, and there should not be any contention with other hosts here!
+	originals, err := GetResources(obj, hostnameFilter, kindFilter)
+	if err != nil {
+		return err
+	}
+
+	if len(originals) == 0 && len(resourceList) == 0 { // special case of no add or del
+		return nil
+	}
+
+	ifs := []etcd.Cmp{} // list matching the desired state
+	ops := []etcd.Op{}  // list of ops in this transaction
+	for _, res := range resourceList {
+		if res.GetKind() == "" {
+			log.Fatalf("Etcd: SetResources: Error: Empty kind: %v", res.GetName())
+		}
+		uid := fmt.Sprintf("%s/%s", res.GetKind(), res.GetName())
+		path := fmt.Sprintf("/%s/exported/%s/resources/%s", NS, hostname, uid)
+		if data, err := resources.ResToB64(res); err == nil {
+			ifs = append(ifs, etcd.Compare(etcd.Value(path), "=", data)) // desired state
+			ops = append(ops, etcd.OpPut(path, data))
+		} else {
+			return fmt.Errorf("can't convert to B64: %v", err)
+		}
+	}
+
+	match := func(res resources.Res, resourceList []resources.Res) bool { // helper lambda
+		for _, x := range resourceList {
+			if res.GetKind() == x.GetKind() && res.GetName() == x.GetName() {
+				return true
+			}
+		}
+		return false
+	}
+
+	hasDeletes := false
+	// delete old, now unused resources here...
+	for _, res := range originals {
+		if res.GetKind() == "" {
+			log.Fatalf("Etcd: SetResources: Error: Empty kind: %v", res.GetName())
+		}
+		uid := fmt.Sprintf("%s/%s", res.GetKind(), res.GetName())
+		path := fmt.Sprintf("/%s/exported/%s/resources/%s", NS, hostname, uid)
+
+		if match(res, resourceList) { // if we match, no need to delete!
+			continue
+		}
+
+		ops = append(ops, etcd.OpDelete(path))
+
+		hasDeletes = true
+	}
+
+	// if everything is already correct, do nothing, otherwise, run the ops!
+	// it's important to do this in one transaction, and atomically, because
+	// this way, we only generate one watch event, and only when it's needed
+	if hasDeletes { // always run, ifs don't matter
+		_, err = obj.Txn(nil, ops, nil) // TODO: does this run? it should!
+	} else {
+		_, err = obj.Txn(ifs, nil, ops) // TODO: do we need to look at response?
+	}
+	return err
+}
+
+// GetResources collects all of the resources which match a filter from etcd.
+// If the kindfilter or hostnameFilter is empty, then it assumes no filtering...
+// TODO: Expand this with a more powerful filter based on what we eventually
+// support in our collect DSL. Ideally a server side filter like WithFilter()
+// We could do this if the pattern was /$NS/exported/$kind/$hostname/$uid = $data.
+func GetResources(obj *EmbdEtcd, hostnameFilter, kindFilter []string) ([]resources.Res, error) {
+	// key structure is /$NS/exported/$hostname/resources/$uid = $data
+	path := fmt.Sprintf("/%s/exported/", NS)
+	resourceList := []resources.Res{}
+	keyMap, err := obj.Get(path, etcd.WithPrefix(), etcd.WithSort(etcd.SortByKey, etcd.SortAscend))
+	if err != nil {
+		return nil, fmt.Errorf("could not get resources: %v", err)
+	}
+	for key, val := range keyMap {
+		if !strings.HasPrefix(key, path) { // sanity check
+			continue
+		}
+
+		str := strings.Split(key[len(path):], "/")
+		if len(str) != 4 {
+			return nil, fmt.Errorf("unexpected chunk count")
+		}
+		hostname, r, kind, name := str[0], str[1], str[2], str[3]
+		if r != "resources" {
+			return nil, fmt.Errorf("unexpected chunk pattern")
+		}
+		if kind == "" {
+			return nil, fmt.Errorf("unexpected kind chunk")
+		}
+
+		// FIXME: ideally this would be a server side filter instead!
+		if len(hostnameFilter) > 0 && !util.StrInList(hostname, hostnameFilter) {
+			continue
+		}
+
+		// FIXME: ideally this would be a server side filter instead!
+		if len(kindFilter) > 0 && !util.StrInList(kind, kindFilter) {
+			continue
+		}
+
+		if obj, err := resources.B64ToRes(val); err == nil {
+			log.Printf("Etcd: Get: (Hostname, Kind, Name): (%s, %s, %s)", hostname, kind, name)
+			resourceList = append(resourceList, obj)
+		} else {
+			return nil, fmt.Errorf("can't convert from B64: %v", err)
+		}
+	}
+	return resourceList, nil
+}

etcd/str.go

@@ -0,0 +1,105 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package etcd
+
+import (
+	"errors"
+	"fmt"
+
+	etcd "github.com/coreos/etcd/clientv3"
+	errwrap "github.com/pkg/errors"
+)
+
+// ErrNotExist is returned when GetStr can not find the requested key.
+// TODO: https://dave.cheney.net/2016/04/07/constant-errors
+var ErrNotExist = errors.New("errNotExist")
+
+// WatchStr returns a channel which spits out events on key activity.
+// FIXME: It should close the channel when it's done, and spit out errors when
+// something goes wrong.
+func WatchStr(obj *EmbdEtcd, key string) chan error {
+	// new key structure is /$NS/strings/$key = $data
+	path := fmt.Sprintf("/%s/strings/%s", NS, key)
+	ch := make(chan error, 1)
+	// FIXME: fix our API so that we get a close event on shutdown.
+	callback := func(re *RE) error {
+		// TODO: is this even needed? it used to happen on conn errors
+		//log.Printf("Etcd: Watch: Path: %v", path) // event
+		if re == nil || re.response.Canceled {
+			return fmt.Errorf("watch is empty") // will cause a CtxError+retry
+		}
+		if len(ch) == 0 { // send event only if one isn't pending
+			ch <- nil // event
+		}
+		return nil
+	}
+	_, _ = obj.AddWatcher(path, callback, true, false, etcd.WithPrefix()) // no need to check errors
+	return ch
+}
+
+// GetStr collects the string which matches a global namespace in etcd.
+func GetStr(obj *EmbdEtcd, key string) (string, error) {
+	// new key structure is /$NS/strings/$key = $data
+	path := fmt.Sprintf("/%s/strings/%s", NS, key)
+	keyMap, err := obj.Get(path, etcd.WithPrefix())
+	if err != nil {
+		return "", errwrap.Wrapf(err, "could not get strings in: %s", key)
+	}
+
+	if len(keyMap) == 0 {
+		return "", ErrNotExist
+	}
+
+	if count := len(keyMap); count != 1 {
+		return "", fmt.Errorf("returned %d entries", count)
+	}
+
+	val, exists := keyMap[path]
+	if !exists {
+		return "", fmt.Errorf("path `%s` is missing", path)
+	}
+
+	//log.Printf("Etcd: GetStr(%s): %s", key, val)
+	return val, nil
+}
+
+// SetStr sets a key and hostname pair to a certain value. If the value is
+// nil, then it deletes the key. Otherwise the value should point to a string.
+// TODO: TTL or delete disconnect?
+func SetStr(obj *EmbdEtcd, key string, data *string) error {
+	// key structure is /$NS/strings/$key = $data
+	path := fmt.Sprintf("/%s/strings/%s", NS, key)
+	ifs := []etcd.Cmp{} // list matching the desired state
+	ops := []etcd.Op{}  // list of ops in this transaction (then)
+	els := []etcd.Op{}  // list of ops in this transaction (else)
+	if data == nil {    // perform a delete
+		// TODO: use https://github.com/coreos/etcd/pull/7417 if merged
+		//ifs = append(ifs, etcd.KeyExists(path))
+		ifs = append(ifs, etcd.Compare(etcd.Version(path), ">", 0))
+		ops = append(ops, etcd.OpDelete(path))
+	} else {
+		data := *data                                                // get the real value
+		ifs = append(ifs, etcd.Compare(etcd.Value(path), "=", data)) // desired state
+		els = append(els, etcd.OpPut(path, data))
+	}
+
+	// it's important to do this in one transaction, and atomically, because
+	// this way, we only generate one watch event, and only when it's needed
+	_, err := obj.Txn(ifs, ops, els) // TODO: do we need to look at response?
+	return errwrap.Wrapf(err, "could not set strings in: %s", key)
+}

etcd/strmap.go

@@ -0,0 +1,115 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package etcd
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/purpleidea/mgmt/util"
+
+	etcd "github.com/coreos/etcd/clientv3"
+	errwrap "github.com/pkg/errors"
+)
+
+// WatchStrMap returns a channel which spits out events on key activity.
+// FIXME: It should close the channel when it's done, and spit out errors when
+// something goes wrong.
+func WatchStrMap(obj *EmbdEtcd, key string) chan error {
+	// new key structure is /$NS/strings/$key/$hostname = $data
+	path := fmt.Sprintf("/%s/strings/%s", NS, key)
+	ch := make(chan error, 1)
+	// FIXME: fix our API so that we get a close event on shutdown.
+	callback := func(re *RE) error {
+		// TODO: is this even needed? it used to happen on conn errors
+		//log.Printf("Etcd: Watch: Path: %v", path) // event
+		if re == nil || re.response.Canceled {
+			return fmt.Errorf("watch is empty") // will cause a CtxError+retry
+		}
+		if len(ch) == 0 { // send event only if one isn't pending
+			ch <- nil // event
+		}
+		return nil
+	}
+	_, _ = obj.AddWatcher(path, callback, true, false, etcd.WithPrefix()) // no need to check errors
+	return ch
+}
+
+// GetStrMap collects all of the strings which match a namespace in etcd.
+func GetStrMap(obj *EmbdEtcd, hostnameFilter []string, key string) (map[string]string, error) {
+	// old key structure is /$NS/strings/$hostname/$key = $data
+	// new key structure is /$NS/strings/$key/$hostname = $data
+	// FIXME: if we have the $key as the last token (old key structure), we
+	// can allow the key to contain the slash char, otherwise we need to
+	// verify that one isn't present in the input string.
+	path := fmt.Sprintf("/%s/strings/%s", NS, key)
+	keyMap, err := obj.Get(path, etcd.WithPrefix(), etcd.WithSort(etcd.SortByKey, etcd.SortAscend))
+	if err != nil {
+		return nil, errwrap.Wrapf(err, "could not get strings in: %s", key)
+	}
+	result := make(map[string]string)
+	for key, val := range keyMap {
+		if !strings.HasPrefix(key, path) { // sanity check
+			continue
+		}
+
+		str := strings.Split(key[len(path):], "/")
+		if len(str) != 2 {
+			return nil, fmt.Errorf("unexpected chunk count of %d", len(str))
+		}
+		_, hostname := str[0], str[1]
+
+		if hostname == "" {
+			return nil, fmt.Errorf("unexpected chunk length of %d", len(hostname))
+		}
+
+		// FIXME: ideally this would be a server side filter instead!
+		if len(hostnameFilter) > 0 && !util.StrInList(hostname, hostnameFilter) {
+			continue
+		}
+		//log.Printf("Etcd: GetStr(%s): (Hostname, Data): (%s, %s)", key, hostname, val)
+		result[hostname] = val
+	}
+	return result, nil
+}
+
+// SetStrMap sets a key and hostname pair to a certain value. If the value is
+// nil, then it deletes the key. Otherwise the value should point to a string.
+// TODO: TTL or delete disconnect?
+func SetStrMap(obj *EmbdEtcd, hostname, key string, data *string) error {
+	// key structure is /$NS/strings/$key/$hostname = $data
+	path := fmt.Sprintf("/%s/strings/%s/%s", NS, key, hostname)
+	ifs := []etcd.Cmp{} // list matching the desired state
+	ops := []etcd.Op{}  // list of ops in this transaction (then)
+	els := []etcd.Op{}  // list of ops in this transaction (else)
+	if data == nil {    // perform a delete
+		// TODO: use https://github.com/coreos/etcd/pull/7417 if merged
+		//ifs = append(ifs, etcd.KeyExists(path))
+		ifs = append(ifs, etcd.Compare(etcd.Version(path), ">", 0))
+		ops = append(ops, etcd.OpDelete(path))
+	} else {
+		data := *data                                                // get the real value
+		ifs = append(ifs, etcd.Compare(etcd.Value(path), "=", data)) // desired state
+		els = append(els, etcd.OpPut(path, data))
+	}
+
+	// it's important to do this in one transaction, and atomically, because
+	// this way, we only generate one watch event, and only when it's needed
+	_, err := obj.Txn(ifs, ops, els) // TODO: do we need to look at response?
+	return errwrap.Wrapf(err, "could not set strings in: %s", key)
+}

etcd/world.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 package etcd
@@ -27,10 +27,16 @@ type World struct {
 	EmbdEtcd *EmbdEtcd
 }
 
+// ResWatch returns a channel which spits out events on possible exported
+// resource changes.
+func (obj *World) ResWatch() chan error {
+	return WatchResources(obj.EmbdEtcd)
+}
+
 // ResExport exports a list of resources under our hostname namespace.
 // Subsequent calls replace the previously set collection atomically.
 func (obj *World) ResExport(resourceList []resources.Res) error {
-	return EtcdSetResources(obj.EmbdEtcd, obj.Hostname, resourceList)
+	return SetResources(obj.EmbdEtcd, obj.Hostname, resourceList)
 }
 
 // ResCollect gets the collection of exported resources which match the filter.
@@ -39,5 +45,51 @@ func (obj *World) ResCollect(hostnameFilter, kindFilter []string) ([]resources.R
 	// XXX: should we be restricted to retrieving resources that were
 	// exported with a tag that allows or restricts our hostname? We could
 	// enforce that here if the underlying API supported it... Add this?
-	return EtcdGetResources(obj.EmbdEtcd, hostnameFilter, kindFilter)
+	return GetResources(obj.EmbdEtcd, hostnameFilter, kindFilter)
+}
+
+// StrWatch returns a channel which spits out events on possible string changes.
+func (obj *World) StrWatch(namespace string) chan error {
+	return WatchStr(obj.EmbdEtcd, namespace)
+}
+
+// StrIsNotExist returns whether the error from StrGet is a key missing error.
+func (obj *World) StrIsNotExist(err error) bool {
+	return err == ErrNotExist
+}
+
+// StrGet returns the value for the the given namespace.
+func (obj *World) StrGet(namespace string) (string, error) {
+	return GetStr(obj.EmbdEtcd, namespace)
+}
+
+// StrSet sets the namespace value to a particular string.
+func (obj *World) StrSet(namespace, value string) error {
+	return SetStr(obj.EmbdEtcd, namespace, &value)
+}
+
+// StrDel deletes the value in a particular namespace.
+func (obj *World) StrDel(namespace string) error {
+	return SetStr(obj.EmbdEtcd, namespace, nil)
+}
+
+// StrMapWatch returns a channel which spits out events on possible string changes.
+func (obj *World) StrMapWatch(namespace string) chan error {
+	return WatchStrMap(obj.EmbdEtcd, namespace)
+}
+
+// StrMapGet returns a map of hostnames to values in the given namespace.
+func (obj *World) StrMapGet(namespace string) (map[string]string, error) {
+	return GetStrMap(obj.EmbdEtcd, []string{}, namespace)
+}
+
+// StrMapSet sets the namespace value to a particular string under the identity
+// of its own hostname.
+func (obj *World) StrMapSet(namespace, value string) error {
+	return SetStrMap(obj.EmbdEtcd, obj.Hostname, namespace, &value)
+}
+
+// StrMapDel deletes the value in a particular namespace.
+func (obj *World) StrMapDel(namespace string) error {
+	return SetStrMap(obj.EmbdEtcd, obj.Hostname, namespace, nil)
 }

event/event.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 // Package event provides some primitives that are used for message passing.
@@ -22,14 +22,14 @@ import (
 	"fmt"
 )
 
-//go:generate stringer -type=EventName -output=eventname_stringer.go
+//go:generate stringer -type=Kind -output=kind_stringer.go
 
-// EventName represents the type of event being passed.
-type EventName int
+// Kind represents the type of event being passed.
+type Kind int
 
-// The different event names are used in different contexts.
+// The different event kinds are used in different contexts.
 const (
-	EventNil EventName = iota
+	EventNil Kind = iota
 	EventExit
 	EventStart
 	EventPause
@@ -43,11 +43,10 @@ type Resp chan error
 
 // Event is the main struct that stores event information and responses.
 type Event struct {
-	Name EventName
+	Kind Kind
 	Resp Resp // channel to send an ack response on, nil to skip
 	//Wg   *sync.WaitGroup // receiver barrier to Wait() for everyone else on
-	Msg      string // some words for fun
-	Activity bool   // did something interesting happen?
+	Err error // store an error in our event
 }
 
 // ACK sends a single acknowledgement on the channel if one was requested.
@@ -80,7 +79,7 @@ func NewResp() Resp {
 // ACK sends a true value to resp.
 func (resp Resp) ACK() {
 	if resp != nil {
-		resp <- nil
+		resp <- nil // TODO: close instead?
 	}
 }
 
@@ -114,7 +113,7 @@ func (resp Resp) ACKWait() {
 	}
 }
 
-// GetActivity returns the activity value.
-func (event *Event) GetActivity() bool {
-	return event.Activity
+// Error returns the stored error value.
+func (event *Event) Error() error {
+	return event.Err
 }

examples/augeas1.yaml

@@ -0,0 +1,11 @@
+---
+graph: mygraph
+resources:
+  augeas:
+  - name: sshd_config
+    lens: Sshd.lns
+    file: "/etc/ssh/sshd_config"
+    sets:
+    - path: X11Forwarding
+      value: false
+edges:

examples/autoedges3.yaml

@@ -5,11 +5,13 @@ resources:
   - name: drbd-utils
     meta:
       autoedge: true
+      noop: true
     state: installed
   file:
   - name: file1
     meta:
       autoedge: true
+      noop: true
     path: "/etc/drbd.conf"
     content: |
       # this is an mgmt test
@@ -17,13 +19,14 @@ resources:
   - name: file2
     meta:
       autoedge: true
+      noop: true
     path: "/etc/drbd.d/"
-    content: |
-      i am a directory
+    source: /dev/null
     state: exists
   svc:
   - name: drbd
     meta:
       autoedge: true
+      noop: true
     state: stopped
 edges: []

examples/autoedges4.yaml

@@ -0,0 +1,19 @@
+---
+graph: mygraph
+resources:
+  user:
+  - name: edgeuser
+    state: absent
+    gid: 10000
+  - name: edgeuser2
+    state: exists
+    group: edgegroup
+    groups: [edgegroup2, edgegroup3]
+  group:
+  - name: edgegroup
+    state: exists
+    gid: 10000
+  - name: edgegroup2
+    state: exists
+  - name: edgegroup3
+    state: exists

examples/aws_ec2_1.yaml

@@ -0,0 +1,10 @@
+---
+graph: mygraph
+resources:
+  aws:ec2:
+  - name: ec2example
+    region: ca-central-1
+    type: t2.micro
+    imageid: ami-5ac17f3e
+    state: running
+edges: []

examples/deep-dirs.yaml

@@ -0,0 +1,9 @@
+---
+graph: mygraph
+resources:
+  file:
+  - name: file1
+    path: "/tmp/mgmt/a/b/c/f1"
+    content: |
+      i am f1
+    state: exists

examples/etcd1a.yaml

@@ -2,15 +2,10 @@
 graph: mygraph
 resources:
   file:
-  - name: file1a
-    path: "/tmp/mgmtA/f1a"
+  - name: "@@filea"
+    path: "/tmp/mgmtA/fA"
     content: |
-      i am f1
-    state: exists
-  - name: "@@file2a"
-    path: "/tmp/mgmtA/f2a"
-    content: |
-      i am f2, exported from host A
+      i am fA, exported from host A
     state: exists
 collect:
 - kind: file

examples/etcd1b.yaml

@@ -2,15 +2,10 @@
 graph: mygraph
 resources:
   file:
-  - name: file1b
-    path: "/tmp/mgmtB/f1b"
+  - name: "@@fileb"
+    path: "/tmp/mgmtB/fB"
     content: |
-      i am f1
-    state: exists
-  - name: "@@file2b"
-    path: "/tmp/mgmtB/f2b"
-    content: |
-      i am f2, exported from host B
+      i am fB, exported from host B
     state: exists
 collect:
 - kind: file

examples/etcd1c.yaml

@@ -2,15 +2,10 @@
 graph: mygraph
 resources:
   file:
-  - name: file1c
-    path: "/tmp/mgmtC/f1c"
+  - name: "@@filec"
+    path: "/tmp/mgmtC/fC"
     content: |
-      i am f1
-    state: exists
-  - name: "@@file2c"
-    path: "/tmp/mgmtC/f2c"
-    content: |
-      i am f2, exported from host C
+      i am fC, exported from host C
     state: exists
 collect:
 - kind: file

examples/etcd1d.yaml

@@ -2,15 +2,10 @@
 graph: mygraph
 resources:
   file:
-  - name: file1d
-    path: "/tmp/mgmtD/f1d"
+  - name: "@@filed"
+    path: "/tmp/mgmtD/fD"
     content: |
-      i am f1
-    state: exists
-  - name: "@@file2d"
-    path: "/tmp/mgmtD/f2d"
-    content: |
-      i am f2, exported from host D
+      i am fD, exported from host D
     state: exists
 collect:
 - kind: file

examples/etcd1e.yaml

@@ -0,0 +1,13 @@
+---
+graph: mygraph
+resources:
+  file:
+  - name: "@@filee"
+    path: "/tmp/mgmtE/fE"
+    content: |
+      i am fE, exported from host E
+    state: exists
+collect:
+- kind: file
+  pattern: "/tmp/mgmtE/"
+edges: []

examples/exec3-sema.yaml

@@ -0,0 +1,67 @@
+---
+graph: parallel
+resources:
+  exec:
+  - name: pkg10
+    meta:
+      sema: ['mylock:1', 'otherlock:42']
+    cmd: sleep 10s
+    shell: ''
+    timeout: 0
+    watchcmd: ''
+    watchshell: ''
+    ifcmd: ''
+    ifshell: ''
+    pollint: 0
+    state: present
+  - name: svc10
+    meta:
+      sema: ['mylock:1']
+    cmd: sleep 10s
+    shell: ''
+    timeout: 0
+    watchcmd: ''
+    watchshell: ''
+    ifcmd: ''
+    ifshell: ''
+    pollint: 0
+    state: present
+  - name: exec10
+    meta:
+      sema: ['mylock:1']
+    cmd: sleep 10s
+    shell: ''
+    timeout: 0
+    watchcmd: ''
+    watchshell: ''
+    ifcmd: ''
+    ifshell: ''
+    pollint: 0
+    state: present
+  - name: pkg15
+    meta:
+      sema: ['mylock:1', 'otherlock:42']
+    cmd: sleep 15s
+    shell: ''
+    timeout: 0
+    watchcmd: ''
+    watchshell: ''
+    ifcmd: ''
+    ifshell: ''
+    pollint: 0
+    state: present
+edges:
+- name: e1
+  from:
+    kind: exec
+    name: pkg10
+  to:
+    kind: exec
+    name: svc10
+- name: e2
+  from:
+    kind: exec
+    name: svc10
+  to:
+    kind: exec
+    name: exec10

examples/file0.yaml

@@ -0,0 +1,10 @@
+---
+graph: mygraph
+resources:
+  file:
+  - name: file0
+    path: "/tmp/mgmt/f1"
+    content: |
+      i am f0
+    state: exists
+edges: []

examples/file3.yaml

@@ -1,14 +1,13 @@
 ---
 graph: mygraph
-comment: You can test Watch and CheckApply failures with chmod ugo-r and chmod ugo-w.
 resources:
   file:
   - name: file1
-    path: "/tmp/mgmt/f1"
     meta:
-      retry: 3
-      delay: 5000
+      limit: .inf
+      burst: 0
+    path: "/tmp/mgmt/hello"
     content: |
-      i am f1
+      i am a file
     state: exists
 edges: []

examples/file4.yaml

@@ -0,0 +1,10 @@
+---
+graph: mygraph
+resources:
+  file:
+  - name: file1
+    path: "/tmp/mgmt/hello"
+    content: |
+      i am a file
+    state: exists
+edges: []

examples/graph0.hcl

@@ -0,0 +1,14 @@
+resource "file" "file1" {
+  path = "/tmp/mgmt-hello-world"
+  content = "hello, world"
+  state = "exists"
+  depends_on = ["noop.noop1", "exec.sleep"]
+}
+
+resource "noop" "noop1" {
+  test = "nil"
+}
+
+resource "exec" "sleep" {
+ cmd = "sleep 10s"
+}

examples/graph1.hcl

@@ -0,0 +1,4 @@
+resource "exec" "exec1" {
+  cmd = "cat /tmp/mgmt-hello-world"
+  state =  "present"
+}

examples/group1.yaml

@@ -0,0 +1,8 @@
+---
+graph: mygraph
+resources:
+  group:
+  - name: testgroup
+    state: exists
+    gid: 10000
+edges: []

examples/hil.hcl

@@ -0,0 +1,9 @@
+resource "file" "file1" {
+  path = "/tmp/mgmt-hello-world"
+  content = "${exec.sleep.Output}"
+  state = "exists"
+}
+
+resource "exec" "sleep" {
+ cmd = "echo hello"
+}

examples/kv1.yaml

@@ -0,0 +1,8 @@
+---
+graph: mygraph
+resources:
+  kv:
+  - name: kv1
+    key: "hello"
+    value: "world"
+edges: []

examples/kv2.yaml

@@ -0,0 +1,7 @@
+---
+graph: mygraph
+resources:
+  kv:
+  - name: kv1
+    key: "iamdeleted"
+edges: []

examples/kv3.yaml

@@ -0,0 +1,9 @@
+---
+graph: mygraph
+resources:
+  kv:
+  - name: kv1
+    key: "stage"
+    value: "3"
+    skiplessthan: true
+edges: []

examples/kv4.yaml

@@ -0,0 +1,31 @@
+---
+graph: mygraph
+resources:
+  kv:
+  - name: kv1
+    key: "stage"
+    value: "1"
+    skiplessthan: true
+  - name: kv2
+    key: "stage"
+    value: "2"
+    skiplessthan: true
+  - name: kv3
+    key: "stage"
+    value: "3"
+    skiplessthan: true
+edges:
+- name: e1
+  from:
+    kind: kv
+    name: kv1
+  to:
+    kind: kv
+    name: kv2
+- name: e2
+  from:
+    kind: kv
+    name: kv2
+  to:
+    kind: kv
+    name: kv3

examples/lib/exec-send-recv.go

@@ -0,0 +1,246 @@
+// libmgmt example of send->recv
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+	"time"
+
+	"github.com/purpleidea/mgmt/gapi"
+	mgmt "github.com/purpleidea/mgmt/lib"
+	"github.com/purpleidea/mgmt/pgraph"
+	"github.com/purpleidea/mgmt/resources"
+)
+
+// MyGAPI implements the main GAPI interface.
+type MyGAPI struct {
+	Name     string // graph name
+	Interval uint   // refresh interval, 0 to never refresh
+
+	data        gapi.Data
+	initialized bool
+	closeChan   chan struct{}
+	wg          sync.WaitGroup // sync group for tunnel go routines
+}
+
+// NewMyGAPI creates a new MyGAPI struct and calls Init().
+func NewMyGAPI(data gapi.Data, name string, interval uint) (*MyGAPI, error) {
+	obj := &MyGAPI{
+		Name:     name,
+		Interval: interval,
+	}
+	return obj, obj.Init(data)
+}
+
+// Init initializes the MyGAPI struct.
+func (obj *MyGAPI) Init(data gapi.Data) error {
+	if obj.initialized {
+		return fmt.Errorf("already initialized")
+	}
+	if obj.Name == "" {
+		return fmt.Errorf("the graph name must be specified")
+	}
+	obj.data = data // store for later
+	obj.closeChan = make(chan struct{})
+	obj.initialized = true
+	return nil
+}
+
+// Graph returns a current Graph.
+func (obj *MyGAPI) Graph() (*pgraph.Graph, error) {
+	if !obj.initialized {
+		return nil, fmt.Errorf("libmgmt: MyGAPI is not initialized")
+	}
+
+	g, err := pgraph.NewGraph(obj.Name)
+	if err != nil {
+		return nil, err
+	}
+
+	metaparams := resources.DefaultMetaParams
+
+	exec1 := &resources.ExecRes{
+		BaseRes: resources.BaseRes{
+			Name:       "exec1",
+			Kind:       "exec",
+			MetaParams: metaparams,
+		},
+		Cmd:   "echo hello world && echo goodbye world 1>&2", // to stdout && stderr
+		Shell: "/bin/bash",
+	}
+	g.AddVertex(exec1)
+
+	output := &resources.FileRes{
+		BaseRes: resources.BaseRes{
+			Name:       "output",
+			Kind:       "file",
+			MetaParams: metaparams,
+			// send->recv!
+			Recv: map[string]*resources.Send{
+				"Content": {Res: exec1, Key: "Output"},
+			},
+		},
+		Path:  "/tmp/mgmt/output",
+		State: "present",
+	}
+	g.AddVertex(output)
+	g.AddEdge(exec1, output, &resources.Edge{Name: "e0"})
+
+	stdout := &resources.FileRes{
+		BaseRes: resources.BaseRes{
+			Name:       "stdout",
+			Kind:       "file",
+			MetaParams: metaparams,
+			// send->recv!
+			Recv: map[string]*resources.Send{
+				"Content": {Res: exec1, Key: "Stdout"},
+			},
+		},
+		Path:  "/tmp/mgmt/stdout",
+		State: "present",
+	}
+	g.AddVertex(stdout)
+	g.AddEdge(exec1, stdout, &resources.Edge{Name: "e1"})
+
+	stderr := &resources.FileRes{
+		BaseRes: resources.BaseRes{
+			Name:       "stderr",
+			Kind:       "file",
+			MetaParams: metaparams,
+			// send->recv!
+			Recv: map[string]*resources.Send{
+				"Content": {Res: exec1, Key: "Stderr"},
+			},
+		},
+		Path:  "/tmp/mgmt/stderr",
+		State: "present",
+	}
+	g.AddVertex(stderr)
+	g.AddEdge(exec1, stderr, &resources.Edge{Name: "e2"})
+
+	//g, err := config.NewGraphFromConfig(obj.data.Hostname, obj.data.World, obj.data.Noop)
+	return g, nil
+}
+
+// Next returns nil errors every time there could be a new graph.
+func (obj *MyGAPI) Next() chan gapi.Next {
+	ch := make(chan gapi.Next)
+	obj.wg.Add(1)
+	go func() {
+		defer obj.wg.Done()
+		defer close(ch) // this will run before the obj.wg.Done()
+		if !obj.initialized {
+			next := gapi.Next{
+				Err:  fmt.Errorf("libmgmt: MyGAPI is not initialized"),
+				Exit: true, // exit, b/c programming error?
+			}
+			ch <- next
+			return
+		}
+		startChan := make(chan struct{}) // start signal
+		close(startChan)                 // kick it off!
+
+		ticker := make(<-chan time.Time)
+		if obj.data.NoStreamWatch || obj.Interval <= 0 {
+			ticker = nil
+		} else {
+			// arbitrarily change graph every interval seconds
+			t := time.NewTicker(time.Duration(obj.Interval) * time.Second)
+			defer t.Stop()
+			ticker = t.C
+		}
+		for {
+			select {
+			case <-startChan: // kick the loop once at start
+				startChan = nil // disable
+				// pass
+			case <-ticker:
+				// pass
+			case <-obj.closeChan:
+				return
+			}
+
+			log.Printf("libmgmt: Generating new graph...")
+			select {
+			case ch <- gapi.Next{}: // trigger a run
+			case <-obj.closeChan:
+				return
+			}
+		}
+	}()
+	return ch
+}
+
+// Close shuts down the MyGAPI.
+func (obj *MyGAPI) Close() error {
+	if !obj.initialized {
+		return fmt.Errorf("libmgmt: MyGAPI is not initialized")
+	}
+	close(obj.closeChan)
+	obj.wg.Wait()
+	obj.initialized = false // closed = true
+	return nil
+}
+
+// Run runs an embedded mgmt server.
+func Run() error {
+
+	obj := &mgmt.Main{}
+	obj.Program = "libmgmt" // TODO: set on compilation
+	obj.Version = "0.0.1"   // TODO: set on compilation
+	obj.TmpPrefix = true    // disable for easy debugging
+	//prefix := "/tmp/testprefix/"
+	//obj.Prefix = &p // enable for easy debugging
+	obj.IdealClusterSize = -1
+	obj.ConvergedTimeout = -1
+	obj.Noop = false // FIXME: careful!
+
+	obj.GAPI = &MyGAPI{ // graph API
+		Name:     "libmgmt", // TODO: set on compilation
+		Interval: 60 * 10,   // arbitrarily change graph every 15 seconds
+	}
+
+	if err := obj.Init(); err != nil {
+		return err
+	}
+
+	// install the exit signal handler
+	exit := make(chan struct{})
+	defer close(exit)
+	go func() {
+		signals := make(chan os.Signal, 1)
+		signal.Notify(signals, os.Interrupt) // catch ^C
+		//signal.Notify(signals, os.Kill) // catch signals
+		signal.Notify(signals, syscall.SIGTERM)
+
+		select {
+		case sig := <-signals: // any signal will do
+			if sig == os.Interrupt {
+				log.Println("Interrupted by ^C")
+				obj.Exit(nil)
+				return
+			}
+			log.Println("Interrupted by signal")
+			obj.Exit(fmt.Errorf("killed by %v", sig))
+			return
+		case <-exit:
+			return
+		}
+	}()
+
+	return obj.Run()
+}
+
+func main() {
+	log.Printf("Hello!")
+	if err := Run(); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+		return
+	}
+	log.Printf("Goodbye!")
+}

examples/lib/libmgmt-subgraph0.go

@@ -0,0 +1,253 @@
+// libmgmt example of flattened subgraph
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+	"time"
+
+	"github.com/purpleidea/mgmt/gapi"
+	mgmt "github.com/purpleidea/mgmt/lib"
+	"github.com/purpleidea/mgmt/pgraph"
+	"github.com/purpleidea/mgmt/resources"
+
+	errwrap "github.com/pkg/errors"
+)
+
+// MyGAPI implements the main GAPI interface.
+type MyGAPI struct {
+	Name     string // graph name
+	Interval uint   // refresh interval, 0 to never refresh
+
+	data        gapi.Data
+	initialized bool
+	closeChan   chan struct{}
+	wg          sync.WaitGroup // sync group for tunnel go routines
+}
+
+// NewMyGAPI creates a new MyGAPI struct and calls Init().
+func NewMyGAPI(data gapi.Data, name string, interval uint) (*MyGAPI, error) {
+	obj := &MyGAPI{
+		Name:     name,
+		Interval: interval,
+	}
+	return obj, obj.Init(data)
+}
+
+// Init initializes the MyGAPI struct.
+func (obj *MyGAPI) Init(data gapi.Data) error {
+	if obj.initialized {
+		return fmt.Errorf("already initialized")
+	}
+	if obj.Name == "" {
+		return fmt.Errorf("the graph name must be specified")
+	}
+	obj.data = data // store for later
+	obj.closeChan = make(chan struct{})
+	obj.initialized = true
+	return nil
+}
+
+func (obj *MyGAPI) subGraph() (*pgraph.Graph, error) {
+	g, err := pgraph.NewGraph(obj.Name)
+	if err != nil {
+		return nil, err
+	}
+
+	metaparams := resources.DefaultMetaParams
+
+	f1 := &resources.FileRes{
+		BaseRes: resources.BaseRes{
+			Name:       "file1",
+			Kind:       "file",
+			MetaParams: metaparams,
+		},
+		Path: "/tmp/mgmt/sub1",
+
+		State: "present",
+	}
+	g.AddVertex(f1)
+
+	n1 := &resources.NoopRes{
+		BaseRes: resources.BaseRes{
+			Name:       "noop1",
+			Kind:       "noop",
+			MetaParams: metaparams,
+		},
+	}
+	g.AddVertex(n1)
+
+	return g, nil
+}
+
+// Graph returns a current Graph.
+func (obj *MyGAPI) Graph() (*pgraph.Graph, error) {
+	if !obj.initialized {
+		return nil, fmt.Errorf("libmgmt: MyGAPI is not initialized")
+	}
+
+	g, err := pgraph.NewGraph(obj.Name)
+	if err != nil {
+		return nil, err
+	}
+
+	metaparams := resources.DefaultMetaParams
+
+	content := "I created a subgraph!\n"
+	f0 := &resources.FileRes{
+		BaseRes: resources.BaseRes{
+			Name:       "README",
+			MetaParams: metaparams,
+		},
+		Path:    "/tmp/mgmt/README",
+		Content: &content,
+		State:   "present",
+	}
+	g.AddVertex(f0)
+
+	subGraph, err := obj.subGraph()
+	if err != nil {
+		return nil, errwrap.Wrapf(err, "running subGraph() failed")
+	}
+
+	edgeGenFn := func(v1, v2 pgraph.Vertex) pgraph.Edge {
+		edge := &resources.Edge{
+			Name: fmt.Sprintf("edge: %s->%s", v1, v2),
+		}
+
+		// if we want to do something specific based on input
+		_, v2IsFile := v2.(*resources.FileRes)
+		if v1 == f0 && v2IsFile {
+			edge.Notify = true
+		}
+
+		return edge
+	}
+	g.AddEdgeVertexGraph(f0, subGraph, edgeGenFn)
+
+	//g, err := config.NewGraphFromConfig(obj.data.Hostname, obj.data.World, obj.data.Noop)
+	return g, nil
+}
+
+// Next returns nil errors every time there could be a new graph.
+func (obj *MyGAPI) Next() chan gapi.Next {
+	ch := make(chan gapi.Next)
+	obj.wg.Add(1)
+	go func() {
+		defer obj.wg.Done()
+		defer close(ch) // this will run before the obj.wg.Done()
+		if !obj.initialized {
+			next := gapi.Next{
+				Err:  fmt.Errorf("libmgmt: MyGAPI is not initialized"),
+				Exit: true, // exit, b/c programming error?
+			}
+			ch <- next
+			return
+		}
+		startChan := make(chan struct{}) // start signal
+		close(startChan)                 // kick it off!
+
+		ticker := make(<-chan time.Time)
+		if obj.data.NoStreamWatch || obj.Interval <= 0 {
+			ticker = nil
+		} else {
+			// arbitrarily change graph every interval seconds
+			t := time.NewTicker(time.Duration(obj.Interval) * time.Second)
+			defer t.Stop()
+			ticker = t.C
+		}
+		for {
+			select {
+			case <-startChan: // kick the loop once at start
+				startChan = nil // disable
+				// pass
+			case <-ticker:
+				// pass
+			case <-obj.closeChan:
+				return
+			}
+
+			log.Printf("libmgmt: Generating new graph...")
+			select {
+			case ch <- gapi.Next{}: // trigger a run
+			case <-obj.closeChan:
+				return
+			}
+		}
+	}()
+	return ch
+}
+
+// Close shuts down the MyGAPI.
+func (obj *MyGAPI) Close() error {
+	if !obj.initialized {
+		return fmt.Errorf("libmgmt: MyGAPI is not initialized")
+	}
+	close(obj.closeChan)
+	obj.wg.Wait()
+	obj.initialized = false // closed = true
+	return nil
+}
+
+// Run runs an embedded mgmt server.
+func Run() error {
+
+	obj := &mgmt.Main{}
+	obj.Program = "libmgmt" // TODO: set on compilation
+	obj.Version = "0.0.1"   // TODO: set on compilation
+	obj.TmpPrefix = true    // disable for easy debugging
+	//prefix := "/tmp/testprefix/"
+	//obj.Prefix = &p // enable for easy debugging
+	obj.IdealClusterSize = -1
+	obj.ConvergedTimeout = -1
+	obj.Noop = false // FIXME: careful!
+
+	obj.GAPI = &MyGAPI{ // graph API
+		Name:     "libmgmt", // TODO: set on compilation
+		Interval: 60 * 10,   // arbitrarily change graph every 15 seconds
+	}
+
+	if err := obj.Init(); err != nil {
+		return err
+	}
+
+	// install the exit signal handler
+	exit := make(chan struct{})
+	defer close(exit)
+	go func() {
+		signals := make(chan os.Signal, 1)
+		signal.Notify(signals, os.Interrupt) // catch ^C
+		//signal.Notify(signals, os.Kill) // catch signals
+		signal.Notify(signals, syscall.SIGTERM)
+
+		select {
+		case sig := <-signals: // any signal will do
+			if sig == os.Interrupt {
+				log.Println("Interrupted by ^C")
+				obj.Exit(nil)
+				return
+			}
+			log.Println("Interrupted by signal")
+			obj.Exit(fmt.Errorf("killed by %v", sig))
+			return
+		case <-exit:
+			return
+		}
+	}()
+
+	return obj.Run()
+}
+
+func main() {
+	log.Printf("Hello!")
+	if err := Run(); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+		return
+	}
+	log.Printf("Goodbye!")
+}

examples/lib/libmgmt-subgraph1.go

@@ -0,0 +1,243 @@
+// libmgmt example of graph resource
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+	"time"
+
+	"github.com/purpleidea/mgmt/gapi"
+	mgmt "github.com/purpleidea/mgmt/lib"
+	"github.com/purpleidea/mgmt/pgraph"
+	"github.com/purpleidea/mgmt/resources"
+)
+
+// MyGAPI implements the main GAPI interface.
+type MyGAPI struct {
+	Name     string // graph name
+	Interval uint   // refresh interval, 0 to never refresh
+
+	data        gapi.Data
+	initialized bool
+	closeChan   chan struct{}
+	wg          sync.WaitGroup // sync group for tunnel go routines
+}
+
+// NewMyGAPI creates a new MyGAPI struct and calls Init().
+func NewMyGAPI(data gapi.Data, name string, interval uint) (*MyGAPI, error) {
+	obj := &MyGAPI{
+		Name:     name,
+		Interval: interval,
+	}
+	return obj, obj.Init(data)
+}
+
+// Init initializes the MyGAPI struct.
+func (obj *MyGAPI) Init(data gapi.Data) error {
+	if obj.initialized {
+		return fmt.Errorf("already initialized")
+	}
+	if obj.Name == "" {
+		return fmt.Errorf("the graph name must be specified")
+	}
+	obj.data = data // store for later
+	obj.closeChan = make(chan struct{})
+	obj.initialized = true
+	return nil
+}
+
+// Graph returns a current Graph.
+func (obj *MyGAPI) Graph() (*pgraph.Graph, error) {
+	if !obj.initialized {
+		return nil, fmt.Errorf("libmgmt: MyGAPI is not initialized")
+	}
+
+	g, err := pgraph.NewGraph(obj.Name)
+	if err != nil {
+		return nil, err
+	}
+
+	metaparams := resources.DefaultMetaParams
+
+	content := "I created a subgraph!\n"
+	f0 := &resources.FileRes{
+		BaseRes: resources.BaseRes{
+			Name:       "README",
+			Kind:       "file",
+			MetaParams: metaparams,
+		},
+		Path:    "/tmp/mgmt/README",
+		Content: &content,
+		State:   "present",
+	}
+	g.AddVertex(f0)
+
+	// create a subgraph to add *into* a graph resource
+	subGraph, err := pgraph.NewGraph(fmt.Sprintf("%s->subgraph", obj.Name))
+	if err != nil {
+		return nil, err
+	}
+
+	// add elements into the sub graph
+	f1 := &resources.FileRes{
+		BaseRes: resources.BaseRes{
+			Name:       "file1",
+			Kind:       "file",
+			MetaParams: metaparams,
+		},
+		Path: "/tmp/mgmt/sub1",
+
+		State: "present",
+	}
+	subGraph.AddVertex(f1)
+
+	n1 := &resources.NoopRes{
+		BaseRes: resources.BaseRes{
+			Name:       "noop1",
+			Kind:       "noop",
+			MetaParams: metaparams,
+		},
+	}
+	subGraph.AddVertex(n1)
+
+	e0 := &resources.Edge{Name: "e0"}
+	e0.Notify = true // send a notification from v0 to v1
+	subGraph.AddEdge(f1, n1, e0)
+
+	// create the actual resource to hold the sub graph
+	subGraphRes0 := &resources.GraphRes{ // TODO: should we name this SubGraphRes ?
+		BaseRes: resources.BaseRes{
+			Name:       "subgraph1",
+			Kind:       "graph",
+			MetaParams: metaparams,
+		},
+		Graph: subGraph,
+	}
+	g.AddVertex(subGraphRes0) // add it to the main graph
+
+	//g, err := config.NewGraphFromConfig(obj.data.Hostname, obj.data.World, obj.data.Noop)
+	return g, nil
+}
+
+// Next returns nil errors every time there could be a new graph.
+func (obj *MyGAPI) Next() chan gapi.Next {
+	ch := make(chan gapi.Next)
+	obj.wg.Add(1)
+	go func() {
+		defer obj.wg.Done()
+		defer close(ch) // this will run before the obj.wg.Done()
+		if !obj.initialized {
+			next := gapi.Next{
+				Err:  fmt.Errorf("libmgmt: MyGAPI is not initialized"),
+				Exit: true, // exit, b/c programming error?
+			}
+			ch <- next
+			return
+		}
+		startChan := make(chan struct{}) // start signal
+		close(startChan)                 // kick it off!
+
+		ticker := make(<-chan time.Time)
+		if obj.data.NoStreamWatch || obj.Interval <= 0 {
+			ticker = nil
+		} else {
+			// arbitrarily change graph every interval seconds
+			t := time.NewTicker(time.Duration(obj.Interval) * time.Second)
+			defer t.Stop()
+			ticker = t.C
+		}
+		for {
+			select {
+			case <-startChan: // kick the loop once at start
+				startChan = nil // disable
+				// pass
+			case <-ticker:
+				// pass
+			case <-obj.closeChan:
+				return
+			}
+
+			log.Printf("libmgmt: Generating new graph...")
+			select {
+			case ch <- gapi.Next{}: // trigger a run
+			case <-obj.closeChan:
+				return
+			}
+		}
+	}()
+	return ch
+}
+
+// Close shuts down the MyGAPI.
+func (obj *MyGAPI) Close() error {
+	if !obj.initialized {
+		return fmt.Errorf("libmgmt: MyGAPI is not initialized")
+	}
+	close(obj.closeChan)
+	obj.wg.Wait()
+	obj.initialized = false // closed = true
+	return nil
+}
+
+// Run runs an embedded mgmt server.
+func Run() error {
+
+	obj := &mgmt.Main{}
+	obj.Program = "libmgmt" // TODO: set on compilation
+	obj.Version = "0.0.1"   // TODO: set on compilation
+	obj.TmpPrefix = true    // disable for easy debugging
+	//prefix := "/tmp/testprefix/"
+	//obj.Prefix = &p // enable for easy debugging
+	obj.IdealClusterSize = -1
+	obj.ConvergedTimeout = -1
+	obj.Noop = false // FIXME: careful!
+
+	obj.GAPI = &MyGAPI{ // graph API
+		Name:     "libmgmt", // TODO: set on compilation
+		Interval: 60 * 10,   // arbitrarily change graph every 15 seconds
+	}
+
+	if err := obj.Init(); err != nil {
+		return err
+	}
+
+	// install the exit signal handler
+	exit := make(chan struct{})
+	defer close(exit)
+	go func() {
+		signals := make(chan os.Signal, 1)
+		signal.Notify(signals, os.Interrupt) // catch ^C
+		//signal.Notify(signals, os.Kill) // catch signals
+		signal.Notify(signals, syscall.SIGTERM)
+
+		select {
+		case sig := <-signals: // any signal will do
+			if sig == os.Interrupt {
+				log.Println("Interrupted by ^C")
+				obj.Exit(nil)
+				return
+			}
+			log.Println("Interrupted by signal")
+			obj.Exit(fmt.Errorf("killed by %v", sig))
+			return
+		case <-exit:
+			return
+		}
+	}()
+
+	return obj.Run()
+}
+
+func main() {
+	log.Printf("Hello!")
+	if err := Run(); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+		return
+	}
+	log.Printf("Goodbye!")
+}

examples/lib/libmgmt1.go

@@ -40,10 +40,10 @@ func NewMyGAPI(data gapi.Data, name string, interval uint) (*MyGAPI, error) {
 // Init initializes the MyGAPI struct.
 func (obj *MyGAPI) Init(data gapi.Data) error {
 	if obj.initialized {
-		return fmt.Errorf("Already initialized!")
+		return fmt.Errorf("already initialized")
 	}
 	if obj.Name == "" {
-		return fmt.Errorf("The graph name must be specified!")
+		return fmt.Errorf("the graph name must be specified")
 	}
 	obj.data = data // store for later
 	obj.closeChan = make(chan struct{})
@@ -57,11 +57,13 @@ func (obj *MyGAPI) Graph() (*pgraph.Graph, error) {
 		return nil, fmt.Errorf("libmgmt: MyGAPI is not initialized")
 	}
 
-	n1, err := resources.NewNoopRes("noop1")
+	n1, err := resources.NewNamedResource("noop", "noop1")
 	if err != nil {
-		return nil, fmt.Errorf("Can't create resource: %v", err)
+		return nil, err
 	}
 
+	// NOTE: This is considered the legacy method to build graphs. Avoid
+	// importing the legacy `yamlgraph` lib if possible for custom graphs.
 	// we can still build a graph via the yaml method
 	gc := &yamlgraph.GraphConfig{
 		Graph: obj.Name,
@@ -70,7 +72,7 @@ func (obj *MyGAPI) Graph() (*pgraph.Graph, error) {
 			Exec:  []*resources.ExecRes{},
 			File:  []*resources.FileRes{},
 			Msg:   []*resources.MsgRes{},
-			Noop:  []*resources.NoopRes{n1},
+			Noop:  []*resources.NoopRes{n1.(*resources.NoopRes)},
 			Pkg:   []*resources.PkgRes{},
 			Svc:   []*resources.SvcRes{},
 			Timer: []*resources.TimerRes{},
@@ -86,28 +88,45 @@ func (obj *MyGAPI) Graph() (*pgraph.Graph, error) {
 }
 
 // Next returns nil errors every time there could be a new graph.
-func (obj *MyGAPI) Next() chan error {
-	if obj.data.NoWatch || obj.Interval <= 0 {
-		return nil
-	}
-	ch := make(chan error)
+func (obj *MyGAPI) Next() chan gapi.Next {
+	ch := make(chan gapi.Next)
 	obj.wg.Add(1)
 	go func() {
 		defer obj.wg.Done()
 		defer close(ch) // this will run before the obj.wg.Done()
 		if !obj.initialized {
-			ch <- fmt.Errorf("libmgmt: MyGAPI is not initialized")
-			return
+			next := gapi.Next{
+				Err:  fmt.Errorf("libmgmt: MyGAPI is not initialized"),
+				Exit: true, // exit, b/c programming error?
+			}
+			ch <- next
 		}
+		startChan := make(chan struct{}) // start signal
+		close(startChan)                 // kick it off!
 
-		// arbitrarily change graph every interval seconds
-		ticker := time.NewTicker(time.Duration(obj.Interval) * time.Second)
-		defer ticker.Stop()
+		ticker := make(<-chan time.Time)
+		if obj.data.NoStreamWatch || obj.Interval <= 0 {
+			ticker = nil
+		} else {
+			// arbitrarily change graph every interval seconds
+			t := time.NewTicker(time.Duration(obj.Interval) * time.Second)
+			defer t.Stop()
+			ticker = t.C
+		}
 		for {
 			select {
-			case <-ticker.C:
-				log.Printf("libmgmt: Generating new graph...")
-				ch <- nil // trigger a run
+			case <-startChan: // kick the loop once at start
+				startChan = nil // disable
+				// pass
+			case <-ticker:
+				// pass
+			case <-obj.closeChan:
+				return
+			}
+
+			log.Printf("libmgmt: Generating new graph...")
+			select {
+			case ch <- gapi.Next{}: // trigger a run
 			case <-obj.closeChan:
 				return
 			}
@@ -164,17 +183,14 @@ func Run() error {
 				return
 			}
 			log.Println("Interrupted by signal")
-			obj.Exit(fmt.Errorf("Killed by %v", sig))
+			obj.Exit(fmt.Errorf("killed by %v", sig))
 			return
 		case <-exit:
 			return
 		}
 	}()
 
-	if err := obj.Run(); err != nil {
-		return err
-	}
-	return nil
+	return obj.Run()
 }
 
 func main() {

examples/lib/libmgmt2.go

@@ -42,10 +42,10 @@ func NewMyGAPI(data gapi.Data, name string, interval uint, count uint) (*MyGAPI,
 // Init initializes the MyGAPI struct.
 func (obj *MyGAPI) Init(data gapi.Data) error {
 	if obj.initialized {
-		return fmt.Errorf("Already initialized!")
+		return fmt.Errorf("already initialized")
 	}
 	if obj.Name == "" {
-		return fmt.Errorf("The graph name must be specified!")
+		return fmt.Errorf("the graph name must be specified")
 	}
 	obj.data = data // store for later
 	obj.closeChan = make(chan struct{})
@@ -59,19 +59,21 @@ func (obj *MyGAPI) Graph() (*pgraph.Graph, error) {
 		return nil, fmt.Errorf("libmgmt: MyGAPI is not initialized")
 	}
 
-	g := pgraph.NewGraph(obj.Name)
-	var vertex *pgraph.Vertex
+	g, err := pgraph.NewGraph(obj.Name)
+	if err != nil {
+		return nil, err
+	}
+	var vertex pgraph.Vertex
 	for i := uint(0); i < obj.Count; i++ {
-		n, err := resources.NewNoopRes(fmt.Sprintf("noop%d", i))
+		n, err := resources.NewNamedResource("noop", fmt.Sprintf("noop%d", i))
 		if err != nil {
-			return nil, fmt.Errorf("Can't create resource: %v", err)
+			return nil, err
 		}
-		v := pgraph.NewVertex(n)
-		g.AddVertex(v)
+		g.AddVertex(n)
 		if i > 0 {
-			g.AddEdge(vertex, v, pgraph.NewEdge(fmt.Sprintf("e%d", i)))
+			g.AddEdge(vertex, n, &resources.Edge{Name: fmt.Sprintf("e%d", i)})
 		}
-		vertex = v // save
+		vertex = n // save
 	}
 
 	//g, err := config.NewGraphFromConfig(obj.data.Hostname, obj.data.World, obj.data.Noop)
@@ -79,28 +81,45 @@ func (obj *MyGAPI) Graph() (*pgraph.Graph, error) {
 }
 
 // Next returns nil errors every time there could be a new graph.
-func (obj *MyGAPI) Next() chan error {
-	if obj.data.NoWatch || obj.Interval <= 0 {
-		return nil
-	}
-	ch := make(chan error)
+func (obj *MyGAPI) Next() chan gapi.Next {
+	ch := make(chan gapi.Next)
 	obj.wg.Add(1)
 	go func() {
 		defer obj.wg.Done()
 		defer close(ch) // this will run before the obj.wg.Done()
 		if !obj.initialized {
-			ch <- fmt.Errorf("libmgmt: MyGAPI is not initialized")
-			return
+			next := gapi.Next{
+				Err:  fmt.Errorf("libmgmt: MyGAPI is not initialized"),
+				Exit: true, // exit, b/c programming error?
+			}
+			ch <- next
 		}
+		startChan := make(chan struct{}) // start signal
+		close(startChan)                 // kick it off!
 
-		// arbitrarily change graph every interval seconds
-		ticker := time.NewTicker(time.Duration(obj.Interval) * time.Second)
-		defer ticker.Stop()
+		ticker := make(<-chan time.Time)
+		if obj.data.NoStreamWatch || obj.Interval <= 0 {
+			ticker = nil
+		} else {
+			// arbitrarily change graph every interval seconds
+			t := time.NewTicker(time.Duration(obj.Interval) * time.Second)
+			defer t.Stop()
+			ticker = t.C
+		}
 		for {
 			select {
-			case <-ticker.C:
-				log.Printf("libmgmt: Generating new graph...")
-				ch <- nil // trigger a run
+			case <-startChan: // kick the loop once at start
+				startChan = nil // disable
+				// pass
+			case <-ticker:
+				// pass
+			case <-obj.closeChan:
+				return
+			}
+
+			log.Printf("libmgmt: Generating new graph...")
+			select {
+			case ch <- gapi.Next{}: // trigger a run
 			case <-obj.closeChan:
 				return
 			}
@@ -158,17 +177,14 @@ func Run(count uint) error {
 				return
 			}
 			log.Println("Interrupted by signal")
-			obj.Exit(fmt.Errorf("Killed by %v", sig))
+			obj.Exit(fmt.Errorf("killed by %v", sig))
 			return
 		case <-exit:
 			return
 		}
 	}()
 
-	if err := obj.Run(); err != nil {
-		return err
-	}
-	return nil
+	return obj.Run()
 }
 
 func main() {

examples/lib/libmgmt3.go

@@ -39,10 +39,10 @@ func NewMyGAPI(data gapi.Data, name string, interval uint) (*MyGAPI, error) {
 // Init initializes the MyGAPI struct.
 func (obj *MyGAPI) Init(data gapi.Data) error {
 	if obj.initialized {
-		return fmt.Errorf("Already initialized!")
+		return fmt.Errorf("already initialized")
 	}
 	if obj.Name == "" {
-		return fmt.Errorf("The graph name must be specified!")
+		return fmt.Errorf("the graph name must be specified")
 	}
 	obj.data = data // store for later
 	obj.closeChan = make(chan struct{})
@@ -56,34 +56,43 @@ func (obj *MyGAPI) Graph() (*pgraph.Graph, error) {
 		return nil, fmt.Errorf("libmgmt: MyGAPI is not initialized")
 	}
 
-	g := pgraph.NewGraph(obj.Name)
+	g, err := pgraph.NewGraph(obj.Name)
+	if err != nil {
+		return nil, err
+	}
+
+	metaparams := resources.DefaultMetaParams
 
 	content := "Delete me to trigger a notification!\n"
 	f0 := &resources.FileRes{
 		BaseRes: resources.BaseRes{
-			Name: "README",
+			Name:       "README",
+			Kind:       "file",
+			MetaParams: metaparams,
 		},
 		Path:    "/tmp/mgmt/README",
 		Content: &content,
 		State:   "present",
 	}
 
-	v0 := pgraph.NewVertex(f0)
-	g.AddVertex(v0)
+	g.AddVertex(f0)
 
 	p1 := &resources.PasswordRes{
 		BaseRes: resources.BaseRes{
-			Name: "password1",
+			Name:       "password1",
+			Kind:       "password",
+			MetaParams: metaparams,
 		},
 		Length: 8,    // generated string will have this many characters
 		Saved:  true, // this causes passwords to be stored in plain text!
 	}
-	v1 := pgraph.NewVertex(p1)
-	g.AddVertex(v1)
+	g.AddVertex(p1)
 
 	f1 := &resources.FileRes{
 		BaseRes: resources.BaseRes{
-			Name: "file1",
+			Name:       "file1",
+			Kind:       "file",
+			MetaParams: metaparams,
 			// send->recv!
 			Recv: map[string]*resources.Send{
 				"Content": {Res: p1, Key: "Password"},
@@ -94,55 +103,72 @@ func (obj *MyGAPI) Graph() (*pgraph.Graph, error) {
 		State: "present",
 	}
 
-	v2 := pgraph.NewVertex(f1)
-	g.AddVertex(v2)
+	g.AddVertex(f1)
 
 	n1 := &resources.NoopRes{
 		BaseRes: resources.BaseRes{
-			Name: "noop1",
+			Name:       "noop1",
+			Kind:       "noop",
+			MetaParams: metaparams,
 		},
 	}
 
-	v3 := pgraph.NewVertex(n1)
-	g.AddVertex(v3)
+	g.AddVertex(n1)
 
-	e0 := pgraph.NewEdge("e0")
-	e0.Notify = true // send a notification from v0 to v1
-	g.AddEdge(v0, v1, e0)
+	e0 := &resources.Edge{Name: "e0"}
+	e0.Notify = true // send a notification from f0 to p1
+	g.AddEdge(f0, p1, e0)
 
-	g.AddEdge(v1, v2, pgraph.NewEdge("e1"))
+	g.AddEdge(p1, f1, &resources.Edge{Name: "e1"})
 
-	e2 := pgraph.NewEdge("e2")
-	e2.Notify = true // send a notification from v2 to v3
-	g.AddEdge(v2, v3, e2)
+	e2 := &resources.Edge{Name: "e2"}
+	e2.Notify = true // send a notification from f1 to n1
+	g.AddEdge(f1, n1, e2)
 
 	//g, err := config.NewGraphFromConfig(obj.data.Hostname, obj.data.World, obj.data.Noop)
 	return g, nil
 }
 
 // Next returns nil errors every time there could be a new graph.
-func (obj *MyGAPI) Next() chan error {
-	if obj.data.NoWatch || obj.Interval <= 0 {
-		return nil
-	}
-	ch := make(chan error)
+func (obj *MyGAPI) Next() chan gapi.Next {
+	ch := make(chan gapi.Next)
 	obj.wg.Add(1)
 	go func() {
 		defer obj.wg.Done()
 		defer close(ch) // this will run before the obj.wg.Done()
 		if !obj.initialized {
-			ch <- fmt.Errorf("libmgmt: MyGAPI is not initialized")
-			return
+			next := gapi.Next{
+				Err:  fmt.Errorf("libmgmt: MyGAPI is not initialized"),
+				Exit: true, // exit, b/c programming error?
+			}
+			ch <- next
 		}
+		startChan := make(chan struct{}) // start signal
+		close(startChan)                 // kick it off!
 
-		// arbitrarily change graph every interval seconds
-		ticker := time.NewTicker(time.Duration(obj.Interval) * time.Second)
-		defer ticker.Stop()
+		ticker := make(<-chan time.Time)
+		if obj.data.NoStreamWatch || obj.Interval <= 0 {
+			ticker = nil
+		} else {
+			// arbitrarily change graph every interval seconds
+			t := time.NewTicker(time.Duration(obj.Interval) * time.Second)
+			defer t.Stop()
+			ticker = t.C
+		}
 		for {
 			select {
-			case <-ticker.C:
-				log.Printf("libmgmt: Generating new graph...")
-				ch <- nil // trigger a run
+			case <-startChan: // kick the loop once at start
+				startChan = nil // disable
+				// pass
+			case <-ticker:
+				// pass
+			case <-obj.closeChan:
+				return
+			}
+
+			log.Printf("libmgmt: Generating new graph...")
+			select {
+			case ch <- gapi.Next{}: // trigger a run
 			case <-obj.closeChan:
 				return
 			}
@@ -201,17 +227,14 @@ func Run() error {
 				return
 			}
 			log.Println("Interrupted by signal")
-			obj.Exit(fmt.Errorf("Killed by %v", sig))
+			obj.Exit(fmt.Errorf("killed by %v", sig))
 			return
 		case <-exit:
 			return
 		}
 	}()
 
-	if err := obj.Run(); err != nil {
-		return err
-	}
-	return nil
+	return obj.Run()
 }
 
 func main() {

examples/limit1.yaml

@@ -0,0 +1,13 @@
+---
+graph: mygraph
+resources:
+  file:
+  - name: file1
+    meta:
+      limit: 0.2
+      burst: 5
+    path: "/tmp/mgmt/limit"
+    content: |
+      i am a normal file
+    state: exists
+edges: []

examples/noop0.yaml

@@ -0,0 +1,7 @@
+---
+graph: mygraph
+comment: simple noop example
+resources:
+  noop:
+  - name: noop0
+edges: []

examples/noop2.yaml

@@ -0,0 +1,30 @@
+---
+graph: mygraph
+comment: dangerous noop example
+resources:
+  noop:
+  - name: noop1
+    meta:
+      noop: true
+  file:
+  - name: file1
+    path: "/tmp/mgmt/hello-noop"
+    content: |
+      hello world from @purpleidea
+    state: exists
+    meta:
+      noop: true
+  exec:
+  - name: exec1
+    meta:
+      noop: true
+    cmd: 'rm -rf /'
+    shell: '/bin/bash'
+    timeout: 0
+    watchcmd: ''
+    watchshell: ''
+    ifcmd: ''
+    ifshell: ''
+    pollint: 0
+    state: present
+edges: []

examples/nspawn1.yaml

@@ -2,6 +2,6 @@
 graph: mygraph
 resources:
   nspawn:
-  - name: mgmt-nspawn1
+  - name: nspawn1
     state: running
 edges: []

examples/nspawn2.yaml

@@ -1,7 +0,0 @@
----
-graph: mygraph
-resources:
-  nspawn:
-  - name: mgmt-nspawn2
-    state: stopped
-edges: []

examples/poll1.yaml

@@ -0,0 +1,24 @@
+---
+graph: mygraph
+resources:
+  file:
+  - name: file1
+    meta:
+      poll: 5
+    path: "/tmp/mgmt/f1"
+    content: |
+      i poll every 5 seconds
+    state: exists
+  - name: file2
+    path: "/tmp/mgmt/f2"
+    content: |
+      i use the event based watcher
+    state: exists
+  - name: file3
+    meta:
+      poll: 1
+    path: "/tmp/mgmt/f3"
+    content: |
+      i poll every second
+    state: exists
+edges: []

examples/retry1.yaml

@@ -0,0 +1,57 @@
+---
+graph: mygraph
+comment: You can test Watch and CheckApply failures with chmod ugo-r and chmod ugo-w.
+resources:
+  exec:
+  - name: exec1
+    cmd: 'touch /tmp/mgmt/no-read && chmod ugo-r /tmp/mgmt/no-read'
+    shell: '/bin/bash'
+    timeout: 0
+    watchcmd: ''
+    watchshell: ''
+    ifcmd: ''
+    ifshell: ''
+    pollint: 0
+    state: present
+  - name: exec2
+    cmd: 'touch /tmp/mgmt/no-write && chmod ugo-w /tmp/mgmt/no-write'
+    shell: '/bin/bash'
+    timeout: 0
+    watchcmd: ''
+    watchshell: ''
+    ifcmd: ''
+    ifshell: ''
+    pollint: 0
+    state: present
+  file:
+  - name: noread
+    path: "/tmp/mgmt/no-read"
+    meta:
+      retry: 3
+      delay: 5000
+    content: |
+      i am f1
+    state: exists
+  - name: nowrite
+    path: "/tmp/mgmt/no-write"
+    meta:
+      retry: 3
+      delay: 5000
+    content: |
+      i am f1
+    state: exists
+edges:
+- name: e1
+  from:
+    kind: exec
+    name: exec1
+  to:
+    kind: file
+    name: noread
+- name: e2
+  from:
+    kind: exec
+    name: exec2
+  to:
+    kind: file
+    name: nowrite

examples/svc2.yaml

@@ -0,0 +1,8 @@
+---
+graph: mygraph
+resources:
+  svc:
+  - name: purpleidea
+    state: running
+    session: true
+edges: []

examples/timer1.yaml

@@ -4,7 +4,7 @@ comment: timer example
 resources:
   timer:
   - name: timer1
-    interval: 30
+    interval: 3
   exec:
   - name: exec1
     cmd: echo hello world

examples/user1.yaml

@@ -0,0 +1,9 @@
+---
+graph: mygraph
+resources:
+  user:
+  - name: testuser
+    uid: 1002
+    gid: 100
+    state: exists
+edges: []

examples/virt4.yaml

@@ -0,0 +1,21 @@
+---
+graph: mygraph
+resources:
+  virt:
+  - name: mgmt4
+    meta:
+      limit: .inf
+      burst: 0
+    uri: 'qemu:///session'
+    cpus: 1
+    maxcpus: 4
+    memory: 524288
+    boot:
+    - hd
+    disk:
+    - type: qcow2
+      source: "~/.local/share/libvirt/images/fedora-23-scratch.qcow2"
+    state: running
+    transient: false
+edges: []
+comment: "qemu-img create -b fedora-23.qcow2 -f qcow2 fedora-23-scratch.qcow2"

gapi/gapi.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 // Package gapi defines the interface that graph API generators must meet.
@@ -23,28 +23,33 @@ import (
 	"github.com/purpleidea/mgmt/resources"
 )
 
-// World is an interface to the rest of the different graph state. It allows
-// the GAPI to store state and exchange information throughout the cluster. It
-// is the interface each machine uses to communicate with the rest of the world.
-type World interface { // TODO: is there a better name for this interface?
-	ResExport([]resources.Res) error
-	// FIXME: should this method take a "filter" data struct instead of many args?
-	ResCollect(hostnameFilter, kindFilter []string) ([]resources.Res, error)
-}
-
 // Data is the set of input values passed into the GAPI structs via Init.
 type Data struct {
-	Hostname string // uuid for the host, required for GAPI
-	World    World
-	Noop     bool
-	NoWatch  bool
+	Hostname      string // uuid for the host, required for GAPI
+	World         resources.World
+	Noop          bool
+	NoConfigWatch bool
+	NoStreamWatch bool
 	// NOTE: we can add more fields here if needed by GAPI endpoints
 }
 
+// Next describes the particular response the GAPI implementer wishes to emit.
+type Next struct {
+	// FIXME: the Fast pause parameter should eventually get replaced with a
+	// "SwitchMethod" parameter or similar that instead lets the implementer
+	// choose between fast pause, slow pause, and interrupt. Interrupt could
+	// be a future extension to the Resource API that lets an Interrupt() be
+	// called if we want to exit immediately from the CheckApply part of the
+	// resource for some reason. For now we'll keep this simple with a bool.
+	Fast bool  // run a fast pause to switch?
+	Exit bool  // should we cause the program to exit? (specify err or not)
+	Err  error // if something goes wrong (use with or without exit!)
+}
+
 // GAPI is a Graph API that represents incoming graphs and change streams.
 type GAPI interface {
 	Init(Data) error               // initializes the GAPI and passes in useful data
 	Graph() (*pgraph.Graph, error) // returns the most recent pgraph
-	Next() chan error              // returns a stream of switch events
+	Next() chan Next               // returns a stream of switch events
 	Close() error                  // shutdown the GAPI
 }

hcl/gapi.go

@@ -0,0 +1,155 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package hcl
+
+import (
+	"fmt"
+	"log"
+	"sync"
+
+	"github.com/purpleidea/mgmt/gapi"
+	"github.com/purpleidea/mgmt/pgraph"
+	"github.com/purpleidea/mgmt/recwatch"
+)
+
+// GAPI ...
+type GAPI struct {
+	File *string
+
+	initialized   bool
+	data          gapi.Data
+	wg            sync.WaitGroup
+	closeChan     chan struct{}
+	configWatcher *recwatch.ConfigWatcher
+}
+
+// NewGAPI ...
+func NewGAPI(data gapi.Data, file *string) (*GAPI, error) {
+	if file == nil {
+		return nil, fmt.Errorf("empty file given")
+	}
+
+	obj := &GAPI{
+		File: file,
+	}
+	return obj, obj.Init(data)
+}
+
+// Init ...
+func (obj *GAPI) Init(d gapi.Data) error {
+	if obj.initialized {
+		return fmt.Errorf("already initialized")
+	}
+
+	if obj.File == nil {
+		return fmt.Errorf("file cannot be nil")
+	}
+
+	obj.data = d
+	obj.closeChan = make(chan struct{})
+	obj.initialized = true
+	obj.configWatcher = recwatch.NewConfigWatcher()
+
+	return nil
+}
+
+// Graph ...
+func (obj *GAPI) Graph() (*pgraph.Graph, error) {
+	config, err := loadHcl(obj.File)
+	if err != nil {
+		return nil, fmt.Errorf("unable to parse graph: %s", err)
+	}
+
+	return graphFromConfig(config, obj.data)
+}
+
+// Next ...
+func (obj *GAPI) Next() chan gapi.Next {
+	ch := make(chan gapi.Next)
+	obj.wg.Add(1)
+
+	go func() {
+		defer obj.wg.Done()
+		defer close(ch)
+		if !obj.initialized {
+			next := gapi.Next{
+				Err:  fmt.Errorf("hcl: GAPI is not initialized"),
+				Exit: true,
+			}
+			ch <- next
+			return
+		}
+		startChan := make(chan struct{}) // start signal
+		close(startChan)                 // kick it off!
+
+		watchChan, configChan := make(chan error), make(chan error)
+		if obj.data.NoConfigWatch {
+			configChan = nil
+		} else {
+			configChan = obj.configWatcher.ConfigWatch(*obj.File) // simple
+		}
+		if obj.data.NoStreamWatch {
+			watchChan = nil
+		} else {
+			watchChan = obj.data.World.ResWatch()
+		}
+
+		for {
+			var err error
+			var ok bool
+
+			select {
+			case <-startChan:
+				startChan = nil
+			case err, ok = <-watchChan:
+			case err, ok = <-configChan:
+				if !ok {
+					return
+				}
+			case <-obj.closeChan:
+				return
+			}
+
+			log.Printf("hcl: generating new graph")
+			next := gapi.Next{
+				Err: err,
+			}
+
+			select {
+			case ch <- next:
+			case <-obj.closeChan:
+				return
+			}
+		}
+	}()
+
+	return ch
+}
+
+// Close ...
+func (obj *GAPI) Close() error {
+	if !obj.initialized {
+		return fmt.Errorf("hcl: GAPI is not initialized")
+	}
+
+	obj.configWatcher.Close()
+	close(obj.closeChan)
+	obj.wg.Wait()
+	obj.initialized = false
+	return nil
+}

hcl/parse.go

@@ -0,0 +1,387 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package hcl
+
+import (
+	"fmt"
+	"io/ioutil"
+	"log"
+	"strings"
+
+	"github.com/hashicorp/hcl"
+	"github.com/hashicorp/hcl/hcl/ast"
+	"github.com/hashicorp/hil"
+	"github.com/purpleidea/mgmt/gapi"
+	hv "github.com/purpleidea/mgmt/hil"
+	"github.com/purpleidea/mgmt/pgraph"
+	"github.com/purpleidea/mgmt/resources"
+)
+
+type collectorResConfig struct {
+	Kind    string
+	Pattern string
+}
+
+// Config defines the structure of the hcl config.
+type Config struct {
+	Resources []*Resource
+	Edges     []*Edge
+	Collector []collectorResConfig
+}
+
+// vertex is the data structure of a vertex.
+type vertex struct {
+	Kind string `hcl:"kind"`
+	Name string `hcl:"name"`
+}
+
+// Edge defines an edge in hcl.
+type Edge struct {
+	Name   string
+	From   vertex
+	To     vertex
+	Notify bool
+}
+
+// Resources define the state for resources.
+type Resources struct {
+	Resources []resources.Res
+}
+
+// Resource ...
+type Resource struct {
+	Name     string
+	Kind     string
+	resource resources.Res
+	Meta     resources.MetaParams
+	deps     []*Edge
+	rcv      map[string]*hv.ResourceVariable
+}
+
+type key struct {
+	kind, name string
+}
+
+func graphFromConfig(c *Config, data gapi.Data) (*pgraph.Graph, error) {
+	var graph *pgraph.Graph
+	var err error
+
+	graph, err = pgraph.NewGraph("Graph")
+	if err != nil {
+		return nil, fmt.Errorf("unable to create graph from config: %s", err)
+	}
+
+	lookup := make(map[key]pgraph.Vertex)
+
+	var keep []pgraph.Vertex
+	var resourceList []resources.Res
+
+	log.Printf("hcl: parsing %d resources", len(c.Resources))
+	for _, r := range c.Resources {
+		res := r.resource
+		kind := r.resource.GetKind()
+
+		log.Printf("hcl: resource \"%s\" \"%s\"", kind, r.Name)
+		if !strings.HasPrefix(res.GetName(), "@@") {
+			fn := func(v pgraph.Vertex) (bool, error) {
+				return resources.VtoR(v).Compare(res), nil
+			}
+			v, err := graph.VertexMatchFn(fn)
+			if err != nil {
+				return nil, fmt.Errorf("could not match vertex: %s", err)
+			}
+			if v == nil {
+				v = res
+				graph.AddVertex(v)
+			}
+			lookup[key{kind, res.GetName()}] = v
+			keep = append(keep, v)
+		} else if !data.Noop {
+			res.SetName(res.GetName()[2:])
+			res.SetKind(kind)
+			resourceList = append(resourceList, res)
+		}
+	}
+
+	// store in backend (usually etcd)
+	if err := data.World.ResExport(resourceList); err != nil {
+		return nil, fmt.Errorf("Config: Could not export resources: %v", err)
+	}
+
+	// lookup from backend (usually etcd)
+	var hostnameFilter []string // empty to get from everyone
+	kindFilter := []string{}
+	for _, t := range c.Collector {
+		kind := strings.ToLower(t.Kind)
+		kindFilter = append(kindFilter, kind)
+	}
+	// do all the graph look ups in one single step, so that if the backend
+	// database changes, we don't have a partial state of affairs...
+	if len(kindFilter) > 0 { // if kindFilter is empty, don't need to do lookups!
+		var err error
+		resourceList, err = data.World.ResCollect(hostnameFilter, kindFilter)
+		if err != nil {
+			return nil, fmt.Errorf("Config: Could not collect resources: %v", err)
+		}
+	}
+	for _, res := range resourceList {
+		matched := false
+		// see if we find a collect pattern that matches
+		for _, t := range c.Collector {
+			kind := strings.ToLower(t.Kind)
+			// use t.Kind and optionally t.Pattern to collect from storage
+			log.Printf("Collect: %v; Pattern: %v", kind, t.Pattern)
+
+			// XXX: expand to more complex pattern matching here...
+			if res.GetKind() != kind {
+				continue
+			}
+
+			if matched {
+				// we've already matched this resource, should we match again?
+				log.Printf("Config: Warning: Matching %s again!", res)
+			}
+			matched = true
+
+			// collect resources but add the noop metaparam
+			//if noop { // now done in mgmtmain
+			//	res.Meta().Noop = noop
+			//}
+
+			if t.Pattern != "" { // XXX: simplistic for now
+				res.CollectPattern(t.Pattern) // res.Dirname = t.Pattern
+			}
+
+			log.Printf("Collect: %s: collected!", res)
+
+			// XXX: similar to other resource add code:
+			// if _, exists := lookup[kind]; !exists {
+			// 	lookup[kind] = make(map[string]pgraph.Vertex)
+			// }
+
+			fn := func(v pgraph.Vertex) (bool, error) {
+				return resources.VtoR(v).Compare(res), nil
+			}
+			v, err := graph.VertexMatchFn(fn)
+			if err != nil {
+				return nil, fmt.Errorf("could not VertexMatchFn() resource: %s", err)
+			}
+			if v == nil { // no match found
+				v = res            // a standalone res can be a vertex
+				graph.AddVertex(v) // call standalone in case not part of an edge
+			}
+			lookup[key{kind, res.GetName()}] = v // used for constructing edges
+			keep = append(keep, v)               // append
+
+			//break // let's see if another resource even matches
+		}
+	}
+
+	for _, r := range c.Resources {
+		for _, e := range r.deps {
+			if _, ok := lookup[key{strings.ToLower(e.From.Kind), e.From.Name}]; !ok {
+				return nil, fmt.Errorf("can't find 'from' name")
+			}
+			if _, ok := lookup[key{strings.ToLower(e.To.Kind), e.To.Name}]; !ok {
+				return nil, fmt.Errorf("can't find 'to' name")
+			}
+			from := lookup[key{strings.ToLower(e.From.Kind), e.From.Name}]
+			to := lookup[key{strings.ToLower(e.To.Kind), e.To.Name}]
+			edge := &resources.Edge{
+				Name:   e.Name,
+				Notify: e.Notify,
+			}
+			graph.AddEdge(from, to, edge)
+		}
+
+		recv := make(map[string]*resources.Send)
+		// build Rcv's from resource variables
+		for k, v := range r.rcv {
+			send, ok := lookup[key{strings.ToLower(v.Kind), v.Name}]
+			if !ok {
+				return nil, fmt.Errorf("resource not found")
+			}
+
+			recv[strings.ToUpper(string(k[0]))+k[1:]] = &resources.Send{
+				Res: resources.VtoR(send),
+				Key: v.Field,
+			}
+
+			to := lookup[key{strings.ToLower(r.Kind), r.Name}]
+			edge := &resources.Edge{
+				Name:   v.Name,
+				Notify: true,
+			}
+			graph.AddEdge(send, to, edge)
+		}
+
+		r.resource.SetRecv(recv)
+	}
+
+	return graph, nil
+}
+
+func loadHcl(f *string) (*Config, error) {
+	if f == nil {
+		return nil, fmt.Errorf("empty file given")
+	}
+
+	data, err := ioutil.ReadFile(*f)
+	if err != nil {
+		return nil, fmt.Errorf("unable to read file: %v", err)
+	}
+
+	file, err := hcl.ParseBytes(data)
+	if err != nil {
+		return nil, fmt.Errorf("unable to parse file: %s", err)
+	}
+
+	config := new(Config)
+
+	list, ok := file.Node.(*ast.ObjectList)
+	if !ok {
+		return nil, fmt.Errorf("unable to parse file: file does not contain root node object")
+	}
+
+	if resources := list.Filter("resource"); len(resources.Items) > 0 {
+		var err error
+		config.Resources, err = loadResourcesHcl(resources)
+		if err != nil {
+			return nil, fmt.Errorf("unable to parse: %s", err)
+		}
+	}
+
+	return config, nil
+}
+
+func loadResourcesHcl(list *ast.ObjectList) ([]*Resource, error) {
+	list = list.Children()
+	if len(list.Items) == 0 {
+		return nil, nil
+	}
+
+	var result []*Resource
+
+	for _, item := range list.Items {
+		kind := item.Keys[0].Token.Value().(string)
+		name := item.Keys[1].Token.Value().(string)
+
+		var listVal *ast.ObjectList
+		if ot, ok := item.Val.(*ast.ObjectType); ok {
+			listVal = ot.List
+		} else {
+			return nil, fmt.Errorf("module '%s': should be an object", name)
+		}
+
+		var params = resources.DefaultMetaParams
+		if o := listVal.Filter("meta"); len(o.Items) > 0 {
+			err := hcl.DecodeObject(&params, o)
+			if err != nil {
+				return nil, fmt.Errorf(
+					"Error parsing meta for %s: %s",
+					name,
+					err)
+			}
+		}
+
+		var deps []string
+		if edges := listVal.Filter("depends_on"); len(edges.Items) > 0 {
+			err := hcl.DecodeObject(&deps, edges.Items[0].Val)
+			if err != nil {
+				return nil, fmt.Errorf("unable to parse: %s", err)
+			}
+		}
+
+		var edges []*Edge
+		for _, dep := range deps {
+			vertices := strings.Split(dep, ".")
+			edges = append(edges, &Edge{
+				To: vertex{
+					Kind: kind,
+					Name: name,
+				},
+				From: vertex{
+					Kind: vertices[0],
+					Name: vertices[1],
+				},
+			})
+		}
+
+		var config map[string]interface{}
+		if err := hcl.DecodeObject(&config, item.Val); err != nil {
+			log.Printf("hcl: unable to decode body: %v", err)
+			return nil, fmt.Errorf(
+				"Error reading config for %s: %s",
+				name,
+				err)
+		}
+
+		delete(config, "meta")
+		delete(config, "depends_on")
+
+		rcv := make(map[string]*hv.ResourceVariable)
+		// parse strings for hil
+		for k, v := range config {
+			n, err := hil.Parse(v.(string))
+			if err != nil {
+				return nil, fmt.Errorf("unable to parse fields: %v", err)
+			}
+
+			variables, err := hv.ParseVariables(n)
+			if err != nil {
+				return nil, fmt.Errorf("unable to parse variables: %v", err)
+			}
+
+			for _, v := range variables {
+				val, ok := v.(*hv.ResourceVariable)
+				if !ok {
+					continue
+				}
+
+				rcv[k] = val
+			}
+		}
+
+		res, err := resources.NewNamedResource(kind, name)
+		if err != nil {
+			log.Printf("hcl: unable to parse resource: %v", err)
+			return nil, err
+		}
+
+		if err := hcl.DecodeObject(res, item.Val); err != nil {
+			log.Printf("hcl: unable to decode body: %v", err)
+			return nil, fmt.Errorf(
+				"Error reading config for %s: %s",
+				name,
+				err)
+		}
+
+		meta := res.Meta()
+		*meta = params
+
+		result = append(result, &Resource{
+			Name:     name,
+			Kind:     kind,
+			resource: res,
+			deps:     edges,
+			rcv:      rcv,
+		})
+	}
+
+	return result, nil
+}

hil/interpolate.go

@@ -0,0 +1,89 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package hil
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/hashicorp/hil/ast"
+)
+
+// Variable defines an interpolated variable.
+type Variable interface {
+	Key() string
+}
+
+// ResourceVariable defines a variable type used to reference fields of a resource
+// e.g.  ${file.file1.Content}
+type ResourceVariable struct {
+	Kind, Name, Field string
+}
+
+// Key returns a string representation of the variable key.
+func (r *ResourceVariable) Key() string {
+	return fmt.Sprintf("%s.%s.%s", r.Kind, r.Name, r.Field)
+}
+
+// NewInterpolatedVariable takes a variable key and return the interpolated variable
+// of the required type.
+func NewInterpolatedVariable(k string) (Variable, error) {
+	// for now resource variables are the only thing.
+	parts := strings.SplitN(k, ".", 3)
+
+	return &ResourceVariable{
+		Kind:  parts[0],
+		Name:  parts[1],
+		Field: parts[2],
+	}, nil
+}
+
+// ParseVariables will traverse a HIL tree looking for variables and returns a
+// list of them.
+func ParseVariables(tree ast.Node) ([]Variable, error) {
+	var result []Variable
+	var finalErr error
+
+	visitor := func(n ast.Node) ast.Node {
+		if finalErr != nil {
+			return n
+		}
+
+		switch nt := n.(type) {
+		case *ast.VariableAccess:
+			v, err := NewInterpolatedVariable(nt.Name)
+			if err != nil {
+				finalErr = err
+				return n
+			}
+			result = append(result, v)
+		default:
+			return n
+		}
+
+		return n
+	}
+
+	tree.Accept(visitor)
+
+	if finalErr != nil {
+		return nil, finalErr
+	}
+
+	return result, nil
+}

lib/cli.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 package lib
@@ -24,8 +24,10 @@ import (
 	"os/signal"
 	"syscall"
 
+	"github.com/purpleidea/mgmt/hcl"
 	"github.com/purpleidea/mgmt/puppet"
 	"github.com/purpleidea/mgmt/yamlgraph"
+	"github.com/purpleidea/mgmt/yamlgraph2"
 
 	"github.com/urfave/cli"
 )
@@ -55,35 +57,55 @@ func run(c *cli.Context) error {
 
 	if _ = c.String("code"); c.IsSet("code") {
 		if obj.GAPI != nil {
-			return fmt.Errorf("Can't combine code GAPI with existing GAPI.")
+			return fmt.Errorf("can't combine code GAPI with existing GAPI")
 		}
 		// TODO: implement DSL GAPI
 		//obj.GAPI = &dsl.GAPI{
 		//	Code: &s,
 		//}
-		return fmt.Errorf("The Code GAPI is not implemented yet!") // TODO: DSL
+		return fmt.Errorf("the Code GAPI is not implemented yet") // TODO: DSL
 	}
 	if y := c.String("yaml"); c.IsSet("yaml") {
 		if obj.GAPI != nil {
-			return fmt.Errorf("Can't combine YAML GAPI with existing GAPI.")
+			return fmt.Errorf("can't combine YAML GAPI with existing GAPI")
 		}
 		obj.GAPI = &yamlgraph.GAPI{
 			File: &y,
 		}
 	}
+	if y := c.String("yaml2"); c.IsSet("yaml2") {
+		if obj.GAPI != nil {
+			return fmt.Errorf("can't combine YAMLv2 GAPI with existing GAPI")
+		}
+		obj.GAPI = &yamlgraph2.GAPI{
+			File: &y,
+		}
+	}
 	if p := c.String("puppet"); c.IsSet("puppet") {
 		if obj.GAPI != nil {
-			return fmt.Errorf("Can't combine puppet GAPI with existing GAPI.")
+			return fmt.Errorf("can't combine puppet GAPI with existing GAPI")
 		}
 		obj.GAPI = &puppet.GAPI{
 			PuppetParam: &p,
 			PuppetConf:  c.String("puppet-conf"),
 		}
 	}
+	if h := c.String("hcl"); c.IsSet("hcl") {
+		if obj.GAPI != nil {
+			return fmt.Errorf("can't combine hcl GAPI with existing GAPI")
+		}
+		obj.GAPI = &hcl.GAPI{
+			File: &h,
+		}
+	}
 	obj.Remotes = c.StringSlice("remote") // FIXME: GAPI-ify somehow?
 
 	obj.NoWatch = c.Bool("no-watch")
+	obj.NoConfigWatch = c.Bool("no-config-watch")
+	obj.NoStreamWatch = c.Bool("no-stream-watch")
+
 	obj.Noop = c.Bool("noop")
+	obj.Sema = c.Int("sema")
 	obj.Graphviz = c.String("graphviz")
 	obj.GraphvizFilter = c.String("graphviz-filter")
 	obj.ConvergedTimeout = c.Int("converged-timeout")
@@ -115,6 +137,9 @@ func run(c *cli.Context) error {
 		return err
 	}
 
+	obj.Prometheus = c.Bool("prometheus")
+	obj.PrometheusListen = c.String("prometheus-listen")
+
 	// install the exit signal handler
 	exit := make(chan struct{})
 	defer close(exit)
@@ -132,7 +157,7 @@ func run(c *cli.Context) error {
 				return
 			}
 			log.Println("Interrupted by signal")
-			obj.Exit(fmt.Errorf("Killed by %v", sig))
+			obj.Exit(fmt.Errorf("killed by %v", sig))
 			return
 		case <-exit:
 			return
@@ -152,7 +177,7 @@ func CLI(program, version string, flags Flags) error {
 
 	// test for sanity
 	if program == "" || version == "" {
-		return fmt.Errorf("Program was not compiled correctly. Please see Makefile.")
+		return fmt.Errorf("program was not compiled correctly, see Makefile")
 	}
 	app := cli.NewApp()
 	app.Name = program // App.name and App.version pass these values through
@@ -201,6 +226,16 @@ func CLI(program, version string, flags Flags) error {
 					Value: "",
 					Usage: "yaml graph definition to run",
 				},
+				cli.StringFlag{
+					Name:  "yaml2",
+					Value: "",
+					Usage: "yaml graph definition to run (parser v2)",
+				},
+				cli.StringFlag{
+					Name:  "hcl",
+					Value: "",
+					Usage: "hcl graph definition to run",
+				},
 				cli.StringFlag{
 					Name:  "puppet, p",
 					Value: "",
@@ -219,12 +254,26 @@ func CLI(program, version string, flags Flags) error {
 
 				cli.BoolFlag{
 					Name:  "no-watch",
+					Usage: "do not update graph under any switch events",
+				},
+				cli.BoolFlag{
+					Name:  "no-config-watch",
+					Usage: "do not update graph on config switch events",
+				},
+				cli.BoolFlag{
+					Name:  "no-stream-watch",
 					Usage: "do not update graph on stream switch events",
 				},
+
 				cli.BoolFlag{
 					Name:  "noop",
 					Usage: "globally force all resources into no-op mode",
 				},
+				cli.IntFlag{
+					Name:  "sema",
+					Value: -1,
+					Usage: "globally add a semaphore to all resources with this lock count",
+				},
 				cli.StringFlag{
 					Name:  "graphviz, g",
 					Value: "",
@@ -232,7 +281,7 @@ func CLI(program, version string, flags Flags) error {
 				},
 				cli.StringFlag{
 					Name:  "graphviz-filter, gf",
-					Value: "dot", // directed graph default
+					Value: "",
 					Usage: "graphviz filter to use",
 				},
 				cli.IntFlag{
@@ -320,6 +369,15 @@ func CLI(program, version string, flags Flags) error {
 					Value: "",
 					Usage: "default identity used for generation",
 				},
+				cli.BoolFlag{
+					Name:  "prometheus",
+					Usage: "start a prometheus instance",
+				},
+				cli.StringFlag{
+					Name:  "prometheus-listen",
+					Value: "",
+					Usage: "specify prometheus instance binding",
+				},
 			},
 		},
 	}

lib/main.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 package lib
@@ -30,6 +30,7 @@ import (
 	"github.com/purpleidea/mgmt/gapi"
 	"github.com/purpleidea/mgmt/pgp"
 	"github.com/purpleidea/mgmt/pgraph"
+	"github.com/purpleidea/mgmt/prometheus"
 	"github.com/purpleidea/mgmt/recwatch"
 	"github.com/purpleidea/mgmt/remote"
 	"github.com/purpleidea/mgmt/resources"
@@ -64,8 +65,12 @@ type Main struct {
 	GAPI    gapi.GAPI // graph API interface struct
 	Remotes []string  // list of remote graph definitions to run
 
-	NoWatch          bool   // do not update graph on watched graph definition file changes
+	NoWatch       bool // do not change graph under any circumstances
+	NoConfigWatch bool // do not update graph due to config changes
+	NoStreamWatch bool // do not update graph due to stream changes
+
 	Noop             bool   // globally force all resources into no-op mode
+	Sema             int    // add a semaphore with this lock count to each resource
 	Graphviz         string // output file for graphviz data
 	GraphvizFilter   string // graphviz filter to use
 	ConvergedTimeout int    // exit after approximately this many seconds in a converged state; -1 to disable
@@ -93,6 +98,9 @@ type Main struct {
 	PgpIdentity *string
 	pgpKeys     *pgp.PGP // agent key pair
 
+	Prometheus       bool   // enable prometheus metrics
+	PrometheusListen string // prometheus instance bind specification
+
 	exit chan error // exit signal
 }
 
@@ -100,11 +108,20 @@ type Main struct {
 func (obj *Main) Init() error {
 
 	if obj.Program == "" || obj.Version == "" {
-		return fmt.Errorf("You must set the Program and Version strings!")
+		return fmt.Errorf("you must set the Program and Version strings")
 	}
 
 	if obj.Prefix != nil && obj.TmpPrefix {
-		return fmt.Errorf("Choosing a prefix and the request for a tmp prefix is illogical!")
+		return fmt.Errorf("choosing a prefix and the request for a tmp prefix is illogical")
+	}
+
+	// if we've turned off watching, then be explicit and disable them all!
+	// if all the watches are disabled, then it's equivalent to no watching
+	if obj.NoWatch {
+		obj.NoConfigWatch = true
+		obj.NoStreamWatch = true
+	} else if obj.NoConfigWatch && obj.NoStreamWatch {
+		obj.NoWatch = true
 	}
 
 	obj.idealClusterSize = uint16(obj.IdealClusterSize)
@@ -113,7 +130,7 @@ func (obj *Main) Init() error {
 	}
 
 	if obj.idealClusterSize < 1 {
-		return fmt.Errorf("IdealClusterSize should be at least one!")
+		return fmt.Errorf("the IdealClusterSize should be at least one")
 	}
 
 	if obj.NoServer && len(obj.Remotes) > 0 {
@@ -121,19 +138,19 @@ func (obj *Main) Init() error {
 		// here, so if we're okay with every remote graph running in an
 		// isolated mode, then this is okay. Improve on this if there's
 		// someone who really wants to be able to do this.
-		return fmt.Errorf("The Server is required when using Remotes!")
+		return fmt.Errorf("the Server is required when using Remotes")
 	}
 
 	if obj.CConns < 0 {
-		return fmt.Errorf("The CConns value should be at least zero!")
+		return fmt.Errorf("the CConns value should be at least zero")
 	}
 
 	if obj.ConvergedTimeout >= 0 && obj.CConns > 0 && len(obj.Remotes) > int(obj.CConns) {
-		return fmt.Errorf("You can't converge if you have more remotes than available connections!")
+		return fmt.Errorf("you can't converge if you have more remotes than available connections")
 	}
 
 	if obj.Depth < 0 { // user should not be using this argument manually
-		return fmt.Errorf("Negative values for Depth are not permitted!")
+		return fmt.Errorf("negative values for Depth are not permitted")
 	}
 
 	// transform the url list inputs into etcd typed lists
@@ -142,19 +159,19 @@ func (obj *Main) Init() error {
 		util.FlattenListWithSplit(obj.Seeds, []string{",", ";", " "}),
 	)
 	if err != nil && len(obj.Seeds) > 0 {
-		return fmt.Errorf("Seeds didn't parse correctly!")
+		return fmt.Errorf("the Seeds didn't parse correctly")
 	}
 	obj.clientURLs, err = etcdtypes.NewURLs(
 		util.FlattenListWithSplit(obj.ClientURLs, []string{",", ";", " "}),
 	)
 	if err != nil && len(obj.ClientURLs) > 0 {
-		return fmt.Errorf("ClientURLs didn't parse correctly!")
+		return fmt.Errorf("the ClientURLs didn't parse correctly")
 	}
 	obj.serverURLs, err = etcdtypes.NewURLs(
 		util.FlattenListWithSplit(obj.ServerURLs, []string{",", ";", " "}),
 	)
 	if err != nil && len(obj.ServerURLs) > 0 {
-		return fmt.Errorf("ServerURLs didn't parse correctly!")
+		return fmt.Errorf("the ServerURLs didn't parse correctly")
 	}
 
 	obj.exit = make(chan error)
@@ -194,10 +211,10 @@ func (obj *Main) Run() error {
 	if h := obj.Hostname; h != nil && *h != "" { // override by cli
 		hostname = *h
 	} else if err != nil {
-		return errwrap.Wrapf(err, "Can't get default hostname!")
+		return errwrap.Wrapf(err, "can't get default hostname")
 	}
 	if hostname == "" { // safety check
-		return fmt.Errorf("Hostname cannot be empty!")
+		return fmt.Errorf("hostname cannot be empty")
 	}
 
 	var prefix = fmt.Sprintf("/var/lib/%s/", obj.Program) // default prefix
@@ -209,24 +226,39 @@ func (obj *Main) Run() error {
 		if obj.TmpPrefix || obj.AllowTmpPrefix {
 			var err error
 			if prefix, err = ioutil.TempDir("", obj.Program+"-"+hostname+"-"); err != nil {
-				return fmt.Errorf("Main: Error: Can't create temporary prefix!")
+				return fmt.Errorf("can't create temporary prefix")
 			}
 			log.Println("Main: Warning: Working prefix directory is temporary!")
 
 		} else {
-			return fmt.Errorf("Main: Error: Can't create prefix!")
+			return fmt.Errorf("can't create prefix")
 		}
 	}
 	log.Printf("Main: Working prefix is: %s", prefix)
 	pgraphPrefix := fmt.Sprintf("%s/", path.Join(prefix, "pgraph")) // pgraph namespace
 	if err := os.MkdirAll(pgraphPrefix, 0770); err != nil {
-		return errwrap.Wrapf(err, "Can't create pgraph prefix")
+		return errwrap.Wrapf(err, "can't create pgraph prefix")
+	}
+
+	var prom *prometheus.Prometheus
+	if obj.Prometheus {
+		prom = &prometheus.Prometheus{
+			Listen: obj.PrometheusListen,
+		}
+		if err := prom.Init(); err != nil {
+			return errwrap.Wrapf(err, "can't create initiate Prometheus instance")
+		}
+
+		log.Printf("Main: Prometheus: Starting instance on %s", prom.Listen)
+		if err := prom.Start(); err != nil {
+			return errwrap.Wrapf(err, "can't start initiate Prometheus instance")
+		}
 	}
 
 	if !obj.NoPgp {
 		pgpPrefix := fmt.Sprintf("%s/", path.Join(prefix, "pgp"))
 		if err := os.MkdirAll(pgpPrefix, 0770); err != nil {
-			return errwrap.Wrapf(err, "Can't create pgp prefix")
+			return errwrap.Wrapf(err, "can't create pgp prefix")
 		}
 
 		pgpKeyringPath := path.Join(pgpPrefix, pgp.DefaultKeyringFile) // default path
@@ -237,7 +269,7 @@ func (obj *Main) Run() error {
 
 		var err error
 		if obj.pgpKeys, err = pgp.Import(pgpKeyringPath); err != nil && !os.IsNotExist(err) {
-			return errwrap.Wrapf(err, "Can't import pgp key")
+			return errwrap.Wrapf(err, "can't import pgp key")
 		}
 
 		if obj.pgpKeys == nil {
@@ -249,24 +281,28 @@ func (obj *Main) Run() error {
 
 			name, comment, email, err := pgp.ParseIdentity(identity)
 			if err != nil {
-				return errwrap.Wrapf(err, "Can't parse user string")
+				return errwrap.Wrapf(err, "can't parse user string")
 
 			}
 
 			// TODO: Make hash configurable
 			if obj.pgpKeys, err = pgp.Generate(name, comment, email, nil); err != nil {
-				return errwrap.Wrapf(err, "Can't creating pgp key")
+				return errwrap.Wrapf(err, "can't create pgp key")
 			}
 
 			if err := obj.pgpKeys.SaveKey(pgpKeyringPath); err != nil {
-				return errwrap.Wrapf(err, "Can't save pgp key")
+				return errwrap.Wrapf(err, "can't save pgp key")
 			}
 		}
 
 		// TODO: Import admin key
 	}
 
-	var G, oldGraph *pgraph.Graph
+	oldGraph := &pgraph.Graph{}
+	graph := &resources.MGraph{}
+	// pass in the information we need
+	graph.Debug = obj.Flags.Debug
+	graph.Init()
 
 	// exit after `max-runtime` seconds for no reason at all...
 	if i := obj.MaxRuntime; i > 0 {
@@ -306,10 +342,20 @@ func (obj *Main) Run() error {
 	)
 	if EmbdEtcd == nil {
 		// TODO: verify EmbdEtcd is not nil below...
-		obj.Exit(fmt.Errorf("Main: Etcd: Creation failed!"))
+		obj.Exit(fmt.Errorf("Main: Etcd: Creation failed"))
 	} else if err := EmbdEtcd.Startup(); err != nil { // startup (returns when etcd main loop is running)
 		obj.Exit(fmt.Errorf("Main: Etcd: Startup failed: %v", err))
 	}
+
+	// wait for etcd server to be ready before continuing...
+	select {
+	case <-EmbdEtcd.ServerReady():
+		log.Printf("Main: Etcd: Server: Ready!")
+		// pass
+	case <-time.After(((etcd.MaxStartServerTimeout * etcd.MaxStartServerRetries) + 1) * time.Second):
+		obj.Exit(fmt.Errorf("Main: Etcd: Startup timeout"))
+	}
+
 	convergerStateFn := func(b bool) error {
 		// exit if we are using the converged timeout and we are the
 		// root node. otherwise, if we are a child node in a remote
@@ -317,58 +363,61 @@ func (obj *Main) Run() error {
 		// state and wait for the parent to trigger the exit.
 		if t := obj.ConvergedTimeout; obj.Depth == 0 && t >= 0 {
 			if b {
-				log.Printf("Converged for %d seconds, exiting!", t)
+				log.Printf("Main: Converged for %d seconds, exiting!", t)
 				obj.Exit(nil) // trigger an exit!
 			}
 			return nil
 		}
 		// send our individual state into etcd for others to see
-		return etcd.EtcdSetHostnameConverged(EmbdEtcd, hostname, b) // TODO: what should happen on error?
+		return etcd.SetHostnameConverged(EmbdEtcd, hostname, b) // TODO: what should happen on error?
 	}
 	if EmbdEtcd != nil {
 		converger.SetStateFn(convergerStateFn)
 	}
 
-	var gapiChan chan error // stream events are nil errors
+	// implementation of the World API (alternates can be substituted in)
+	world := &etcd.World{
+		Hostname: hostname,
+		EmbdEtcd: EmbdEtcd,
+	}
+
+	graph.Data = &resources.ResData{
+		Hostname:   hostname,
+		Converger:  converger,
+		Prometheus: prom,
+		World:      world,
+		Prefix:     pgraphPrefix,
+		Debug:      obj.Flags.Debug,
+	}
+
+	var gapiChan chan gapi.Next // stream events contain some instructions!
 	if obj.GAPI != nil {
 		data := gapi.Data{
 			Hostname: hostname,
-			// NOTE: alternate implementations can be substituted in
-			World: &etcd.World{
-				Hostname: hostname,
-				EmbdEtcd: EmbdEtcd,
-			},
-			Noop:    obj.Noop,
-			NoWatch: obj.NoWatch,
+			World:    world,
+			Noop:     obj.Noop,
+			//NoWatch:  obj.NoWatch,
+			NoConfigWatch: obj.NoConfigWatch,
+			NoStreamWatch: obj.NoStreamWatch,
 		}
 		if err := obj.GAPI.Init(data); err != nil {
 			obj.Exit(fmt.Errorf("Main: GAPI: Init failed: %v", err))
-		} else if !obj.NoWatch {
+		} else {
+			// this must generate at least one event for it to work
 			gapiChan = obj.GAPI.Next() // stream of graph switch events!
 		}
 	}
 
 	exitchan := make(chan struct{}) // exit on close
 	go func() {
-		startChan := make(chan struct{}) // start signal
-		go func() { startChan <- struct{}{} }()
-
-		log.Println("Etcd: Starting...")
-		etcdChan := etcd.EtcdWatch(EmbdEtcd)
 		first := true // first loop or not
 		for {
 			log.Println("Main: Waiting...")
+			// The GAPI should always kick off an event on Next() at
+			// startup when (and if) it indeed has a graph to share!
+			fastPause := false
 			select {
-			case <-startChan: // kick the loop once at start
-				// pass
-
-			case b := <-etcdChan:
-				if !b { // ignore the message
-					continue
-				}
-				// everything else passes through to cause a compile!
-
-			case err, ok := <-gapiChan:
+			case next, ok := <-gapiChan:
 				if !ok { // channel closed
 					if obj.Flags.Debug {
 						log.Printf("Main: GAPI exited")
@@ -376,96 +425,159 @@ func (obj *Main) Run() error {
 					gapiChan = nil // disable it
 					continue
 				}
-				if err != nil {
-					obj.Exit(err) // trigger exit
-					continue
-					//return // TODO: return or wait for exitchan?
+
+				// if we've been asked to exit...
+				if next.Exit {
+					obj.Exit(next.Err) // trigger exit
+					continue           // wait for exitchan
 				}
-				if obj.NoWatch { // extra safety for bad GAPI's
-					log.Printf("Main: GAPI stream should be quiet with NoWatch!") // fix the GAPI!
-					continue                                                      // no stream events should be sent
+
+				// the gapi lets us send an error to the channel
+				// this means there was a failure, but not fatal
+				if err := next.Err; err != nil {
+					log.Printf("Main: Error with graph stream: %v", err)
+					continue // wait for another event
 				}
+				// everything else passes through to cause a compile!
+
+				fastPause = next.Fast // should we pause fast?
 
 			case <-exitchan:
 				return
 			}
 
 			if obj.GAPI == nil {
-				log.Printf("Config: GAPI is empty!")
+				log.Printf("Main: GAPI is empty!")
 				continue
 			}
 
 			// we need the vertices to be paused to work on them, so
 			// run graph vertex LOCK...
 			if !first { // TODO: we can flatten this check out I think
-				converger.Pause() // FIXME: add sync wait?
-				G.Pause()         // sync
+				converger.Pause()      // FIXME: add sync wait?
+				graph.Pause(fastPause) // sync
 
-				//G.UnGroup() // FIXME: implement me if needed!
+				//graph.UnGroup() // FIXME: implement me if needed!
 			}
 
 			// make the graph from yaml, lib, puppet->yaml, or dsl!
 			newGraph, err := obj.GAPI.Graph() // generate graph!
 			if err != nil {
-				log.Printf("Config: Error creating new graph: %v", err)
+				log.Printf("Main: Error creating new graph: %v", err)
 				// unpause!
 				if !first {
-					G.Start(first)    // sync
-					converger.Start() // after G.Start()
+					graph.Start(first) // sync
+					converger.Start()  // after Start()
 				}
 				continue
 			}
-			newGraph.Flags = pgraph.Flags{Debug: obj.Flags.Debug}
-			// pass in the information we need
-			newGraph.AssociateData(&resources.Data{
-				Converger: converger,
-				Prefix:    pgraphPrefix,
-				Debug:     obj.Flags.Debug,
-			})
+			if obj.Flags.Debug {
+				log.Printf("Main: New Graph: %v", newGraph)
+			}
 
-			// apply the global noop parameter if requested
-			if obj.Noop {
-				for _, m := range newGraph.GraphMetas() {
+			// this edits the paused vertices, but it is safe to do
+			// so even if we don't use this new graph, since those
+			// value should be the same for existing vertices...
+			for _, v := range newGraph.Vertices() {
+				m := resources.VtoR(v).Meta()
+				// apply the global noop parameter if requested
+				if obj.Noop {
 					m.Noop = obj.Noop
 				}
+
+				// append the semaphore to each resource
+				if obj.Sema > 0 { // NOTE: size == 0 would block
+					// a semaphore with an empty id is valid
+					m.Sema = append(m.Sema, fmt.Sprintf(":%d", obj.Sema))
+				}
 			}
 
-			// FIXME: make sure we "UnGroup()" any semi-destructive
-			// changes to the resources so our efficient GraphSync
-			// will be able to re-use and cmp to the old graph.
-			newFullGraph, err := newGraph.GraphSync(oldGraph)
-			if err != nil {
-				log.Printf("Config: Error running graph sync: %v", err)
+			// We don't have to "UnGroup()" to compare, since we
+			// save the old graph to use when we compare.
+			// TODO: Does this hurt performance or graph changes ?
+			log.Printf("Main: GraphSync...")
+			vertexCmpFn := func(v1, v2 pgraph.Vertex) (bool, error) {
+				return resources.VtoR(v1).Compare(resources.VtoR(v2)), nil
+			}
+			vertexAddFn := func(v pgraph.Vertex) error {
+				err := resources.VtoR(v).Validate()
+				return errwrap.Wrapf(err, "could not Validate() resource")
+			}
+			vertexRemoveFn := func(v pgraph.Vertex) error {
+				// wait for exit before starting new graph!
+				resources.VtoR(v).Exit() // sync
+				return nil
+			}
+			edgeCmpFn := func(e1, e2 pgraph.Edge) (bool, error) {
+				edge1 := e1.(*resources.Edge) // panic if wrong
+				edge2 := e2.(*resources.Edge) // panic if wrong
+				return edge1.Compare(edge2), nil
+			}
+			// on success, this updates the receiver graph...
+			if err := oldGraph.GraphSync(newGraph, vertexCmpFn, vertexAddFn, vertexRemoveFn, edgeCmpFn); err != nil {
+				log.Printf("Main: Error running graph sync: %v", err)
 				// unpause!
 				if !first {
-					G.Start(first)    // sync
-					converger.Start() // after G.Start()
+					graph.Start(first) // sync
+					converger.Start()  // after Start()
 				}
 				continue
 			}
-			oldGraph = newFullGraph // save old graph
-			G = oldGraph.Copy()     // copy to active graph
 
-			G.AutoEdges() // add autoedges; modifies the graph
-			G.AutoGroup() // run autogroup; modifies the graph
+			//savedGraph := oldGraph.Copy() // save a copy for errors
+
+			// TODO: should we call each Res.Setup() here instead?
+
+			// add autoedges; modifies the graph only if no error
+			if err := resources.AutoEdges(oldGraph); err != nil {
+				log.Printf("Main: Error running auto edges: %v", err)
+				// unpause!
+				if !first {
+					graph.Start(first) // sync
+					converger.Start()  // after Start()
+				}
+				continue
+			}
+
+			// at this point, any time we error after a destructive
+			// modification of the graph we need to restore the old
+			// graph that was previously running, eg:
+			//
+			//	oldGraph = savedGraph.Copy()
+			//
+			// which we are (luckily) able to avoid testing for now
+
+			resources.AutoGroup(oldGraph, &resources.NonReachabilityGrouper{}) // run autogroup; modifies the graph
 			// TODO: do we want to do a transitive reduction?
 			// FIXME: run a type checker that verifies all the send->recv relationships
 
-			log.Printf("Graph: %v", G) // show graph
-			if obj.GraphvizFilter != "" {
-				if err := G.ExecGraphviz(obj.GraphvizFilter, obj.Graphviz); err != nil {
-					log.Printf("Graphviz: %v", err)
-				} else {
-					log.Printf("Graphviz: Successfully generated graph!")
-				}
+			graph.Update(oldGraph) // copy in structure of new graph
+
+			// Call this here because at this point the graph does
+			// not know anything about the prometheus instance.
+			if err := prom.UpdatePgraphStartTime(); err != nil {
+				log.Printf("Main: Prometheus.UpdatePgraphStartTime() errored: %v", err)
 			}
-			// G.Start(...) needs to be synchronous or wait,
+			// Start() needs to be synchronous or wait,
 			// because if half of the nodes are started and
 			// some are not ready yet and the EtcdWatch
-			// loops, we'll cause G.Pause(...) before we
+			// loops, we'll cause Pause() before we
 			// even got going, thus causing nil pointer errors
-			G.Start(first)    // sync
-			converger.Start() // after G.Start()
+			graph.Start(first) // sync
+			converger.Start()  // after Start()
+
+			log.Printf("Main: Graph: %v", graph) // show graph
+			if obj.Graphviz != "" {
+				filter := obj.GraphvizFilter
+				if filter == "" {
+					filter = "dot" // directed graph default
+				}
+				if err := graph.ExecGraphviz(filter, obj.Graphviz, hostname); err != nil {
+					log.Printf("Main: Graphviz: %v", err)
+				} else {
+					log.Printf("Main: Graphviz: Successfully generated graph!")
+				}
+			}
 			first = false
 		}
 	}()
@@ -473,7 +585,7 @@ func (obj *Main) Run() error {
 	configWatcher := recwatch.NewConfigWatcher()
 	configWatcher.Flags = recwatch.Flags{Debug: obj.Flags.Debug}
 	events := configWatcher.Events()
-	if !obj.NoWatch {
+	if !obj.NoWatch { // FIXME: fit this into a clean GAPI?
 		configWatcher.Add(obj.Remotes...) // add all the files...
 	} else {
 		events = nil // signal that no-watch is true
@@ -490,7 +602,7 @@ func (obj *Main) Run() error {
 
 	// initialize the add watcher, which calls the f callback on map changes
 	convergerCb := func(f func(map[string]bool) error) (func(), error) {
-		return etcd.EtcdAddHostnameConvergedWatcher(EmbdEtcd, f)
+		return etcd.AddHostnameConvergedWatcher(EmbdEtcd, f)
 	}
 
 	// build remotes struct for remote ssh
@@ -517,6 +629,14 @@ func (obj *Main) Run() error {
 	// TODO: is there any benefit to running the remotes above in the loop?
 	// wait for etcd to be running before we remote in, which we do above!
 	go remotes.Run()
+	// wait for remotes to be ready before continuing...
+	select {
+	case <-remotes.Ready():
+		log.Printf("Main: Remotes: Run: Ready!")
+		// pass
+		//case <-time.After( ? * time.Second):
+		//	obj.Exit(fmt.Errorf("Main: Remotes: Run timeout"))
+	}
 
 	if obj.GAPI == nil {
 		converger.Start() // better start this for empty graphs
@@ -525,34 +645,42 @@ func (obj *Main) Run() error {
 
 	reterr := <-obj.exit // wait for exit signal
 
-	log.Println("Destroy...")
+	log.Println("Main: Destroy...")
 
 	if obj.GAPI != nil {
 		if err := obj.GAPI.Close(); err != nil {
-			err = errwrap.Wrapf(err, "GAPI closed poorly!")
+			err = errwrap.Wrapf(err, "the GAPI closed poorly")
 			reterr = multierr.Append(reterr, err) // list of errors
 		}
 	}
 
 	configWatcher.Close()                  // stop sending file changes to remotes
 	if err := remotes.Exit(); err != nil { // tell all the remote connections to shutdown; waits!
-		err = errwrap.Wrapf(err, "Remote exited poorly!")
+		err = errwrap.Wrapf(err, "the Remote exited poorly")
 		reterr = multierr.Append(reterr, err) // list of errors
 	}
 
 	// tell inner main loop to exit
 	close(exitchan)
 
-	G.Exit() // tell all the children to exit, and waits for them to do so
+	graph.Exit() // tells all the children to exit, and waits for them to do so
 
 	// cleanup etcd main loop last so it can process everything first
 	if err := EmbdEtcd.Destroy(); err != nil { // shutdown and cleanup etcd
-		err = errwrap.Wrapf(err, "Etcd exited poorly!")
+		err = errwrap.Wrapf(err, "embedded Etcd exited poorly")
 		reterr = multierr.Append(reterr, err) // list of errors
 	}
 
+	if obj.Prometheus {
+		log.Printf("Main: Prometheus: Stopping instance")
+		if err := prom.Stop(); err != nil {
+			err = errwrap.Wrapf(err, "the Prometheus instance exited poorly")
+			reterr = multierr.Append(reterr, err)
+		}
+	}
+
 	if obj.Flags.Debug {
-		log.Printf("Main: Graph: %v", G)
+		log.Printf("Main: Graph: %v", graph)
 	}
 
 	// TODO: wait for each vertex to exit...

main.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 package main

misc/delta-cpu.sh

@@ -0,0 +1,81 @@
+#!/bin/bash
+# shitty cpu count control, useful for live demos
+
+minimum=1	# don't decrease below this number of cpus
+maximum=8	# don't increase above this number of cpus
+count=1		# initial count
+factor=3
+function output() {
+count=$1	# arg!
+cat << EOF > ~/code/mgmt/examples/virt4.yaml
+---
+graph: mygraph
+resources:
+  virt:
+  - name: mgmt4
+    meta:
+      limit: .inf
+      burst: 0
+    uri: 'qemu:///session'
+    cpus: $count
+    maxcpus: $maximum
+    memory: 524288
+    boot:
+    - hd
+    disk:
+    - type: qcow2
+      source: "~/.local/share/libvirt/images/fedora-23-scratch.qcow2"
+    state: running
+    transient: false
+edges: []
+comment: "qemu-img create -b fedora-23.qcow2 -f qcow2 fedora-23-scratch.qcow2"
+EOF
+}
+#tput cuu 1 && tput el	# remove last line
+str=''
+tnuoc=$((maximum-count))	# backwards count
+count2=$((count * factor))
+tnuoc2=$((tnuoc * factor))
+left=`yes '>' | head -$count2 | paste -s -d '' -`
+right=`yes ' ' | head -$tnuoc2 | paste -s -d '' -`
+str="${left}${right}"
+_min=$((minimum-1))
+_max=$((maximum+1))
+reset	# clean up once...
+output $count	# call function
+while true; do
+
+	read -n1 -r -s -p "CPUs count is: $count; ${str} Press +/- key to adjust." key
+	if [ "$key" = "q" ] || [ "$key" = "Q" ]; then
+		echo	# newline
+		exit
+	fi
+	if [ ! "$key" = "+" ] && [ ! "$key" = "-" ] && [ ! "$key" = "=" ] && [ ! "$key" = "_" ]; then	# wrong key
+		reset	# woops, reset it all...
+		continue
+	fi
+	if [ "$key" == "+" ] || [ "$key" == "=" ]; then
+		count=$((count+1))
+	fi
+	if [ "$key" == "-" ] || [ "$key" == "_" ]; then
+		count=$((count-1))
+	fi
+	if [ $count -eq $_min ]; then	# min
+		count=$minimum
+	fi
+	if [ $count -eq $_max ]; then	# max
+		count=$maximum
+	fi
+
+	tnuoc=$((maximum-count))	# backwards count
+	#echo "count is: $count"
+	#echo "tnuoc is: $tnuoc"
+	count2=$((count * factor))
+	tnuoc2=$((tnuoc * factor))
+	left=`yes '>' | head -$count2 | paste -s -d '' -`
+	right=`yes ' ' | head -$tnuoc2 | paste -s -d '' -`
+	str="${left}${right}"
+	#echo "str is: $str"
+	echo -ne '\r'	# backup
+	output $count	# call function
+done

misc/make-deps.sh

@@ -14,26 +14,38 @@ sudo_command=$(which sudo)
 YUM=`which yum 2>/dev/null`
 DNF=`which dnf 2>/dev/null`
 APT=`which apt-get 2>/dev/null`
+BREW=`which brew 2>/dev/null`
+PACMAN=`which pacman 2>/dev/null`
 
 # if DNF is available use it
 if [ -x "$DNF" ]; then
 	YUM=$DNF
 fi
 
-if [ -z "$YUM" -a -z "$APT" ]; then
+if [ -z "$YUM" -a -z "$APT" -a -z "$BREW" -a -z "$PACMAN" ]; then
 	echo "The package managers can't be found."
 	exit 1
 fi
 
 if [ ! -z "$YUM" ]; then
 	$sudo_command $YUM install -y libvirt-devel
+	$sudo_command $YUM install -y augeas-devel
 
 fi
 if [ ! -z "$APT" ]; then
 	$sudo_command $APT install -y libvirt-dev || true
+	$sudo_command $APT install -y libaugeas-dev || true
 	$sudo_command $APT install -y libpcap0.8-dev || true
 fi
 
+if [ ! -z "$BREW" ]; then
+	$BREW install libvirt || true
+fi
+
+if [ ! -z "$PACMAN" ]; then
+	$sudo_command $PACMAN -S --noconfirm libvirt augeas libpcap
+fi
+
 if [ $travis -eq 0 ]; then
 	if [ ! -z "$YUM" ]; then
 		# some go dependencies are stored in mercurial
@@ -47,11 +59,14 @@ if [ $travis -eq 0 ]; then
 		$sudo_command $APT install -y golang-golang-x-tools || true
 		$sudo_command $APT install -y golang-go.tools || true
 	fi
+	if [ ! -z "$PACMAN" ]; then
+		$sudo_command $PACMAN -S --noconfirm go
+	fi
 fi
 
 # if golang is too old, we don't want to fail with an obscure error later
-if go version | grep 'go1\.[0123]\.'; then
-	echo "mgmt requires go1.4 or higher."
+if go version | grep 'go1\.[012345]\.'; then
+	echo "mgmt requires go1.6 or higher."
 	exit 1
 fi
 
@@ -65,4 +80,5 @@ if [[ $ret != 0 ]]; then
 fi
 go get golang.org/x/tools/cmd/stringer	# for automatic stringer-ing
 go get github.com/golang/lint/golint	# for `golint`-ing
+go get -u gopkg.in/alecthomas/gometalinter.v1 && mv "$(dirname $(which gometalinter.v1))/gometalinter.v1" "$(dirname $(which gometalinter.v1))/gometalinter" && gometalinter --install	# bonus
 cd "$XPWD" >/dev/null

misc/mgmt.service

@@ -5,7 +5,7 @@ After=systemd-networkd.service
 Requires=systemd-networkd.service
 
 [Service]
-ExecStart=/usr/bin/mgmt run ${OPTS}
+ExecStart=/usr/bin/mgmt run $OPTS
 RestartSec=5s
 Restart=always
 

pgp/pgp.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 package pgp

pgraph/actions.go

@@ -1,535 +0,0 @@
-// Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
-// Written by James Shubin <james@shubin.ca> and the project contributors
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
-//
-// You should have received a copy of the GNU Affero General Public License
-// along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-package pgraph
-
-import (
-	"fmt"
-	"log"
-	"math"
-	"sync"
-	"time"
-
-	"github.com/purpleidea/mgmt/event"
-	"github.com/purpleidea/mgmt/resources"
-
-	errwrap "github.com/pkg/errors"
-)
-
-// GetTimestamp returns the timestamp of a vertex
-func (v *Vertex) GetTimestamp() int64 {
-	return v.timestamp
-}
-
-// UpdateTimestamp updates the timestamp on a vertex and returns the new value
-func (v *Vertex) UpdateTimestamp() int64 {
-	v.timestamp = time.Now().UnixNano() // update
-	return v.timestamp
-}
-
-// OKTimestamp returns true if this element can run right now?
-func (g *Graph) OKTimestamp(v *Vertex) bool {
-	// these are all the vertices pointing TO v, eg: ??? -> v
-	for _, n := range g.IncomingGraphVertices(v) {
-		// if the vertex has a greater timestamp than any pre-req (n)
-		// then we can't run right now...
-		// if they're equal (eg: on init of 0) then we also can't run
-		// b/c we should let our pre-req's go first...
-		x, y := v.GetTimestamp(), n.GetTimestamp()
-		if g.Flags.Debug {
-			log.Printf("%s[%s]: OKTimestamp: (%v) >= %s[%s](%v): !%v", v.Kind(), v.GetName(), x, n.Kind(), n.GetName(), y, x >= y)
-		}
-		if x >= y {
-			return false
-		}
-	}
-	return true
-}
-
-// Poke notifies nodes after me in the dependency graph that they need refreshing...
-// NOTE: this assumes that this can never fail or need to be rescheduled
-func (g *Graph) Poke(v *Vertex, activity bool) error {
-	var wg sync.WaitGroup
-	// these are all the vertices pointing AWAY FROM v, eg: v -> ???
-	for _, n := range g.OutgoingGraphVertices(v) {
-		// XXX: if we're in state event and haven't been cancelled by
-		// apply, then we can cancel a poke to a child, right? XXX
-		// XXX: if n.Res.getState() != resources.ResStateEvent || activity { // is this correct?
-		if true || activity { // XXX: ???
-			if g.Flags.Debug {
-				log.Printf("%s[%s]: Poke: %s[%s]", v.Kind(), v.GetName(), n.Kind(), n.GetName())
-			}
-			wg.Add(1)
-			go func(nn *Vertex) error {
-				defer wg.Done()
-				edge := g.Adjacency[v][nn] // lookup
-				notify := edge.Notify && edge.Refresh()
-
-				// FIXME: is it okay that this is sync?
-				nn.SendEvent(event.EventPoke, true, notify)
-				// TODO: check return value?
-				return nil // never error for now...
-			}(n)
-
-		} else {
-			if g.Flags.Debug {
-				log.Printf("%s[%s]: Poke: %s[%s]: Skipped!", v.Kind(), v.GetName(), n.Kind(), n.GetName())
-			}
-		}
-	}
-	wg.Wait() // wait for all the pokes to complete
-	return nil
-}
-
-// BackPoke pokes the pre-requisites that are stale and need to run before I can run.
-func (g *Graph) BackPoke(v *Vertex) {
-	// these are all the vertices pointing TO v, eg: ??? -> v
-	for _, n := range g.IncomingGraphVertices(v) {
-		x, y, s := v.GetTimestamp(), n.GetTimestamp(), n.Res.GetState()
-		// if the parent timestamp needs poking AND it's not in state
-		// ResStateEvent, then poke it. If the parent is in ResStateEvent it
-		// means that an event is pending, so we'll be expecting a poke
-		// back soon, so we can safely discard the extra parent poke...
-		// TODO: implement a stateLT (less than) to tell if something
-		// happens earlier in the state cycle and that doesn't wrap nil
-		if x >= y && (s != resources.ResStateEvent && s != resources.ResStateCheckApply) {
-			if g.Flags.Debug {
-				log.Printf("%s[%s]: BackPoke: %s[%s]", v.Kind(), v.GetName(), n.Kind(), n.GetName())
-			}
-			// FIXME: is it okay that this is sync?
-			n.SendEvent(event.EventBackPoke, true, false)
-		} else {
-			if g.Flags.Debug {
-				log.Printf("%s[%s]: BackPoke: %s[%s]: Skipped!", v.Kind(), v.GetName(), n.Kind(), n.GetName())
-			}
-		}
-	}
-}
-
-// RefreshPending determines if any previous nodes have a refresh pending here.
-// If this is true, it means I am expected to apply a refresh when I next run.
-func (g *Graph) RefreshPending(v *Vertex) bool {
-	var refresh bool
-	for _, edge := range g.IncomingGraphEdges(v) {
-		// if we asked for a notify *and* if one is pending!
-		if edge.Notify && edge.Refresh() {
-			refresh = true
-			break
-		}
-	}
-	return refresh
-}
-
-// SetUpstreamRefresh sets the refresh value to any upstream vertices.
-func (g *Graph) SetUpstreamRefresh(v *Vertex, b bool) {
-	for _, edge := range g.IncomingGraphEdges(v) {
-		if edge.Notify {
-			edge.SetRefresh(b)
-		}
-	}
-}
-
-// SetDownstreamRefresh sets the refresh value to any downstream vertices.
-func (g *Graph) SetDownstreamRefresh(v *Vertex, b bool) {
-	for _, edge := range g.OutgoingGraphEdges(v) {
-		// if we asked for a notify *and* if one is pending!
-		if edge.Notify {
-			edge.SetRefresh(b)
-		}
-	}
-}
-
-// Process is the primary function to execute for a particular vertex in the graph.
-func (g *Graph) Process(v *Vertex) error {
-	obj := v.Res
-	if g.Flags.Debug {
-		log.Printf("%s[%s]: Process()", obj.Kind(), obj.GetName())
-	}
-	obj.SetState(resources.ResStateEvent)
-	var ok = true
-	var applied = false // did we run an apply?
-	// is it okay to run dependency wise right now?
-	// if not, that's okay because when the dependency runs, it will poke
-	// us back and we will run if needed then!
-	if g.OKTimestamp(v) {
-		if g.Flags.Debug {
-			log.Printf("%s[%s]: OKTimestamp(%v)", obj.Kind(), obj.GetName(), v.GetTimestamp())
-		}
-
-		obj.SetState(resources.ResStateCheckApply)
-
-		// connect any senders to receivers and detect if values changed
-		if updated, err := obj.SendRecv(obj); err != nil {
-			return errwrap.Wrapf(err, "could not SendRecv in Process")
-		} else if len(updated) > 0 {
-			for _, changed := range updated {
-				if changed { // at least one was updated
-					obj.StateOK(false) // invalidate cache, mark as dirty
-					break
-				}
-			}
-		}
-
-		var noop = obj.Meta().Noop // lookup the noop value
-		var refresh bool
-		var checkOK bool
-		var err error
-
-		if g.Flags.Debug {
-			log.Printf("%s[%s]: CheckApply(%t)", obj.Kind(), obj.GetName(), !noop)
-		}
-
-		// lookup the refresh (notification) variable
-		refresh = g.RefreshPending(v) // do i need to perform a refresh?
-		obj.SetRefresh(refresh)       // tell the resource
-
-		// check cached state, to skip CheckApply; can't skip if refreshing
-		if !refresh && obj.IsStateOK() {
-			checkOK, err = true, nil
-
-			// NOTE: technically this block is wrong because we don't know
-			// if the resource implements refresh! If it doesn't, we could
-			// skip this, but it doesn't make a big difference under noop!
-		} else if noop && refresh { // had a refresh to do w/ noop!
-			checkOK, err = false, nil // therefore the state is wrong
-
-			// run the CheckApply!
-		} else {
-			// if this fails, don't UpdateTimestamp()
-			checkOK, err = obj.CheckApply(!noop)
-		}
-
-		if checkOK && err != nil { // should never return this way
-			log.Fatalf("%s[%s]: CheckApply(): %t, %+v", obj.Kind(), obj.GetName(), checkOK, err)
-		}
-		if g.Flags.Debug {
-			log.Printf("%s[%s]: CheckApply(): %t, %v", obj.Kind(), obj.GetName(), checkOK, err)
-		}
-
-		// if CheckApply ran without noop and without error, state should be good
-		if !noop && err == nil { // aka !noop || checkOK
-			obj.StateOK(true) // reset
-			if refresh {
-				g.SetUpstreamRefresh(v, false) // refresh happened, clear the request
-				obj.SetRefresh(false)
-			}
-		}
-
-		if !checkOK { // if state *was* not ok, we had to have apply'ed
-			if err != nil { // error during check or apply
-				ok = false
-			} else {
-				applied = true
-			}
-		}
-
-		// when noop is true we always want to update timestamp
-		if noop && err == nil {
-			ok = true
-		}
-
-		if ok {
-			// did we actually do work?
-			activity := applied
-			if noop {
-				activity = false // no we didn't do work...
-			}
-
-			if activity { // add refresh flag to downstream edges...
-				g.SetDownstreamRefresh(v, true)
-			}
-
-			// update this timestamp *before* we poke or the poked
-			// nodes might fail due to having a too old timestamp!
-			v.UpdateTimestamp()                    // this was touched...
-			obj.SetState(resources.ResStatePoking) // can't cancel parent poke
-			if err := g.Poke(v, activity); err != nil {
-				return errwrap.Wrapf(err, "the Poke() failed")
-			}
-		}
-		// poke at our pre-req's instead since they need to refresh/run...
-		return errwrap.Wrapf(err, "could not Process() successfully")
-	}
-	// else... only poke at the pre-req's that need to run
-	go g.BackPoke(v)
-	return nil
-}
-
-// SentinelErr is a sentinal as an error type that wraps an arbitrary error.
-type SentinelErr struct {
-	err error
-}
-
-// Error is the required method to fulfill the error type.
-func (obj *SentinelErr) Error() string {
-	return obj.err.Error()
-}
-
-// Worker is the common run frontend of the vertex. It handles all of the retry
-// and retry delay common code, and ultimately returns the final status of this
-// vertex execution.
-func (g *Graph) Worker(v *Vertex) error {
-	// listen for chan events from Watch() and run
-	// the Process() function when they're received
-	// this avoids us having to pass the data into
-	// the Watch() function about which graph it is
-	// running on, which isolates things nicely...
-	obj := v.Res
-	// TODO: is there a better system for the `Watching` flag?
-	obj.SetWatching(true)
-	defer obj.SetWatching(false)
-	processChan := make(chan event.Event)
-	go func() {
-		running := false
-		var timer = time.NewTimer(time.Duration(math.MaxInt64)) // longest duration
-		if !timer.Stop() {
-			<-timer.C // unnecessary, shouldn't happen
-		}
-		var delay = time.Duration(v.Meta().Delay) * time.Millisecond
-		var retry = v.Meta().Retry // number of tries left, -1 for infinite
-		var saved event.Event
-	Loop:
-		for {
-			// this has to be synchronous, because otherwise the Res
-			// event loop will keep running and change state,
-			// causing the converged timeout to fire!
-			select {
-			case event, ok := <-processChan: // must use like this
-				if running && ok {
-					// we got an event that wasn't a close,
-					// while we were waiting for the timer!
-					// if this happens, it might be a bug:(
-					log.Fatalf("%s[%s]: Worker: Unexpected event: %+v", v.Kind(), v.GetName(), event)
-				}
-				if !ok { // processChan closed, let's exit
-					break Loop // no event, so no ack!
-				}
-
-				// the above mentioned synchronous part, is the
-				// running of this function, paired with an ack.
-				if e := g.Process(v); e != nil {
-					saved = event
-					log.Printf("%s[%s]: CheckApply errored: %v", v.Kind(), v.GetName(), e)
-					if retry == 0 {
-						// wrap the error in the sentinel
-						event.ACKNACK(&SentinelErr{e}) // fail the Watch()
-						break Loop
-					}
-					if retry > 0 { // don't decrement the -1
-						retry--
-					}
-					log.Printf("%s[%s]: CheckApply: Retrying after %.4f seconds (%d left)", v.Kind(), v.GetName(), delay.Seconds(), retry)
-					// start the timer...
-					timer.Reset(delay)
-					running = true
-					continue
-				}
-				retry = v.Meta().Retry // reset on success
-				event.ACK()            // sync
-
-			case <-timer.C:
-				if !timer.Stop() {
-					//<-timer.C // blocks, docs are wrong!
-				}
-				running = false
-				log.Printf("%s[%s]: CheckApply delay expired!", v.Kind(), v.GetName())
-				// re-send this failed event, to trigger a CheckApply()
-				go func() { processChan <- saved }()
-				// TODO: should we send a fake event instead?
-				//saved = nil
-			}
-		}
-	}()
-	var err error // propagate the error up (this is a permanent BAD error!)
-	// the watch delay runs inside of the Watch resource loop, so that it
-	// can still process signals and exit if needed. It shouldn't run any
-	// resource specific code since this is supposed to be a retry delay.
-	// NOTE: we're using the same retry and delay metaparams that CheckApply
-	// uses. This is for practicality. We can separate them later if needed!
-	var watchDelay time.Duration
-	var watchRetry = v.Meta().Retry // number of tries left, -1 for infinite
-	// watch blocks until it ends, & errors to retry
-	for {
-		// TODO: do we have to stop the converged-timeout when in this block (perhaps we're in the delay block!)
-		// TODO: should we setup/manage some of the converged timeout stuff in here anyways?
-
-		// if a retry-delay was requested, wait, but don't block our events!
-		if watchDelay > 0 {
-			//var pendingSendEvent bool
-			timer := time.NewTimer(watchDelay)
-		Loop:
-			for {
-				select {
-				case <-timer.C: // the wait is over
-					break Loop // critical
-
-				// TODO: resources could have a separate exit channel to avoid this complexity!?
-				case event := <-obj.Events():
-					// NOTE: this code should match the similar Res code!
-					//cuid.SetConverged(false) // TODO: ?
-					if exit, send := obj.ReadEvent(&event); exit {
-						return nil // exit
-					} else if send {
-						// if we dive down this rabbit hole, our
-						// timer.C won't get seen until we get out!
-						// in this situation, the Watch() is blocked
-						// from performing until CheckApply returns
-						// successfully, or errors out. This isn't
-						// so bad, but we should document it. Is it
-						// possible that some resource *needs* Watch
-						// to run to be able to execute a CheckApply?
-						// That situation shouldn't be common, and
-						// should probably not be allowed. Can we
-						// avoid it though?
-						//if exit, err := doSend(); exit || err != nil {
-						//	return err // we exit or bubble up a NACK...
-						//}
-						// Instead of doing the above, we can
-						// add events to a pending list, and
-						// when we finish the delay, we can run
-						// them.
-						//pendingSendEvent = true // all events are identical for now...
-					}
-				}
-			}
-			timer.Stop() // it's nice to cleanup
-			log.Printf("%s[%s]: Watch delay expired!", v.Kind(), v.GetName())
-			// NOTE: we can avoid the send if running Watch guarantees
-			// one CheckApply event on startup!
-			//if pendingSendEvent { // TODO: should this become a list in the future?
-			//	if exit, err := obj.DoSend(processChan, ""); exit || err != nil {
-			//		return err // we exit or bubble up a NACK...
-			//	}
-			//}
-		}
-
-		// TODO: reset the watch retry count after some amount of success
-		v.Res.RegisterConverger()
-		e := v.Res.Watch(processChan)
-		v.Res.UnregisterConverger()
-		if e == nil { // exit signal
-			err = nil // clean exit
-			break
-		}
-		if sentinelErr, ok := e.(*SentinelErr); ok { // unwrap the sentinel
-			err = sentinelErr.err
-			break // sentinel means, perma-exit
-		}
-		log.Printf("%s[%s]: Watch errored: %v", v.Kind(), v.GetName(), e)
-		if watchRetry == 0 {
-			err = fmt.Errorf("Permanent watch error: %v", e)
-			break
-		}
-		if watchRetry > 0 { // don't decrement the -1
-			watchRetry--
-		}
-		watchDelay = time.Duration(v.Meta().Delay) * time.Millisecond
-		log.Printf("%s[%s]: Watch: Retrying after %.4f seconds (%d left)", v.Kind(), v.GetName(), watchDelay.Seconds(), watchRetry)
-		// We need to trigger a CheckApply after Watch restarts, so that
-		// we catch any lost events that happened while down. We do this
-		// by getting the Watch resource to send one event once it's up!
-		//v.SendEvent(eventPoke, false, false)
-	}
-	close(processChan)
-	return err
-}
-
-// Start is a main kick to start the graph. It goes through in reverse topological
-// sort order so that events can't hit un-started vertices.
-func (g *Graph) Start(first bool) { // start or continue
-	log.Printf("State: %v -> %v", g.setState(graphStateStarting), g.getState())
-	defer log.Printf("State: %v -> %v", g.setState(graphStateStarted), g.getState())
-	var wg sync.WaitGroup
-	t, _ := g.TopologicalSort()
-	// TODO: only calculate indegree if `first` is true to save resources
-	indegree := g.InDegree() // compute all of the indegree's
-	for _, v := range Reverse(t) {
-		// selective poke: here we reduce the number of initial pokes
-		// to the minimum required to activate every vertex in the
-		// graph, either by direct action, or by getting poked by a
-		// vertex that was previously activated. if we poke each vertex
-		// that has no incoming edges, then we can be sure to reach the
-		// whole graph. Please note: this may mask certain optimization
-		// failures, such as any poke limiting code in Poke() or
-		// BackPoke(). You might want to disable this selective start
-		// when experimenting with and testing those elements.
-		// if we are unpausing (since it's not the first run of this
-		// function) we need to poke to *unpause* every graph vertex,
-		// and not just selectively the subset with no indegree.
-		if (!first) || indegree[v] == 0 {
-			v.Res.Starter(true) // let the startup code know to poke
-		}
-
-		if !v.Res.IsWatching() { // if Watch() is not running...
-			g.wg.Add(1)
-			// must pass in value to avoid races...
-			// see: https://ttboj.wordpress.com/2015/07/27/golang-parallelism-issues-causing-too-many-open-files-error/
-			go func(vv *Vertex) {
-				defer g.wg.Done()
-				// TODO: if a sufficient number of workers error,
-				// should something be done? Will these restart
-				// after perma-failure if we have a graph change?
-				if err := g.Worker(vv); err != nil { // contains the Watch and CheckApply loops
-					log.Printf("%s[%s]: Exited with failure: %v", vv.Kind(), vv.GetName(), err)
-					return
-				}
-				log.Printf("%s[%s]: Exited", vv.Kind(), vv.GetName())
-			}(v)
-		}
-
-		// let the vertices run their startup code in parallel
-		wg.Add(1)
-		go func(vv *Vertex) {
-			defer wg.Done()
-			vv.Res.Started() // block until started
-		}(v)
-
-		if !first { // unpause!
-			v.Res.SendEvent(event.EventStart, true, false) // sync!
-		}
-	}
-
-	wg.Wait() // wait for everyone
-}
-
-// Pause sends pause events to the graph in a topological sort order.
-func (g *Graph) Pause() {
-	log.Printf("State: %v -> %v", g.setState(graphStatePausing), g.getState())
-	defer log.Printf("State: %v -> %v", g.setState(graphStatePaused), g.getState())
-	t, _ := g.TopologicalSort()
-	for _, v := range t { // squeeze out the events...
-		v.SendEvent(event.EventPause, true, false)
-	}
-}
-
-// Exit sends exit events to the graph in a topological sort order.
-func (g *Graph) Exit() {
-	if g == nil {
-		return
-	} // empty graph that wasn't populated yet
-	t, _ := g.TopologicalSort()
-	for _, v := range t { // squeeze out the events...
-		// turn off the taps...
-		// XXX: consider instead doing this by closing the Res.events channel instead?
-		// XXX: do this by sending an exit signal, and then returning
-		// when we hit the 'default' in the select statement!
-		// XXX: we can do this to quiesce, but it's not necessary now
-
-		v.SendEvent(event.EventExit, true, false)
-	}
-	g.wg.Wait() // for now, this doesn't need to be a separate Wait() method
-}

pgraph/autoedge.go

@@ -1,103 +0,0 @@
-// Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
-// Written by James Shubin <james@shubin.ca> and the project contributors
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
-//
-// You should have received a copy of the GNU Affero General Public License
-// along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-// Package pgraph represents the internal "pointer graph" that we use.
-package pgraph
-
-import (
-	"fmt"
-	"log"
-
-	"github.com/purpleidea/mgmt/resources"
-)
-
-// add edges to the vertex in a graph based on if it matches a uid list
-func (g *Graph) addEdgesByMatchingUIDS(v *Vertex, uids []resources.ResUID) []bool {
-	// search for edges and see what matches!
-	var result []bool
-
-	// loop through each uid, and see if it matches any vertex
-	for _, uid := range uids {
-		var found = false
-		// uid is a ResUID object
-		for _, vv := range g.GetVertices() { // search
-			if v == vv { // skip self
-				continue
-			}
-			if g.Flags.Debug {
-				log.Printf("Compile: AutoEdge: Match: %v[%v] with UID: %v[%v]", vv.Kind(), vv.GetName(), uid.Kind(), uid.GetName())
-			}
-			// we must match to an effective UID for the resource,
-			// that is to say, the name value of a res is a helpful
-			// handle, but it is not necessarily a unique identity!
-			// remember, resources can return multiple UID's each!
-			if resources.UIDExistsInUIDs(uid, vv.GetUIDs()) {
-				// add edge from: vv -> v
-				if uid.Reversed() {
-					txt := fmt.Sprintf("AutoEdge: %v[%v] -> %v[%v]", vv.Kind(), vv.GetName(), v.Kind(), v.GetName())
-					log.Printf("Compile: Adding %v", txt)
-					g.AddEdge(vv, v, NewEdge(txt))
-				} else { // edges go the "normal" way, eg: pkg resource
-					txt := fmt.Sprintf("AutoEdge: %v[%v] -> %v[%v]", v.Kind(), v.GetName(), vv.Kind(), vv.GetName())
-					log.Printf("Compile: Adding %v", txt)
-					g.AddEdge(v, vv, NewEdge(txt))
-				}
-				found = true
-				break
-			}
-		}
-		result = append(result, found)
-	}
-	return result
-}
-
-// AutoEdges adds the automatic edges to the graph.
-func (g *Graph) AutoEdges() {
-	log.Println("Compile: Adding AutoEdges...")
-	for _, v := range g.GetVertices() { // for each vertexes autoedges
-		if !v.Meta().AutoEdge { // is the metaparam true?
-			continue
-		}
-		autoEdgeObj := v.AutoEdges()
-		if autoEdgeObj == nil {
-			log.Printf("%v[%v]: Config: No auto edges were found!", v.Kind(), v.GetName())
-			continue // next vertex
-		}
-
-		for { // while the autoEdgeObj has more uids to add...
-			uids := autoEdgeObj.Next() // get some!
-			if uids == nil {
-				log.Printf("%v[%v]: Config: The auto edge list is empty!", v.Kind(), v.GetName())
-				break // inner loop
-			}
-			if g.Flags.Debug {
-				log.Println("Compile: AutoEdge: UIDS:")
-				for i, u := range uids {
-					log.Printf("Compile: AutoEdge: UID%d: %v", i, u)
-				}
-			}
-
-			// match and add edges
-			result := g.addEdgesByMatchingUIDS(v, uids)
-
-			// report back, and find out if we should continue
-			if !autoEdgeObj.Test(result) {
-				break
-			}
-		}
-	}
-}

pgraph/graphsync.go

@@ -0,0 +1,155 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package pgraph
+
+import (
+	"fmt"
+
+	errwrap "github.com/pkg/errors"
+)
+
+func strVertexCmpFn(v1, v2 Vertex) (bool, error) {
+	if v1.String() == "" || v2.String() == "" {
+		return false, fmt.Errorf("empty vertex")
+	}
+	return v1.String() == v2.String(), nil
+}
+
+func strEdgeCmpFn(e1, e2 Edge) (bool, error) {
+	if e1.String() == "" || e2.String() == "" {
+		return false, fmt.Errorf("empty edge")
+	}
+	return e1.String() == e2.String(), nil
+}
+
+// GraphSync updates the Graph so that it matches the newGraph. It leaves
+// identical elements alone so that they don't need to be refreshed.
+// It tries to mutate existing elements into new ones, if they support this.
+// This updates the Graph on success only.
+// FIXME: should we do this with copies of the vertex resources?
+func (obj *Graph) GraphSync(newGraph *Graph, vertexCmpFn func(Vertex, Vertex) (bool, error), vertexAddFn func(Vertex) error, vertexRemoveFn func(Vertex) error, edgeCmpFn func(Edge, Edge) (bool, error)) error {
+
+	oldGraph := obj.Copy() // work on a copy of the old graph
+	if oldGraph == nil {
+		var err error
+		oldGraph, err = NewGraph(newGraph.GetName()) // copy over the name
+		if err != nil {
+			return errwrap.Wrapf(err, "GraphSync failed")
+		}
+	}
+	oldGraph.SetName(newGraph.GetName()) // overwrite the name
+
+	if vertexCmpFn == nil {
+		vertexCmpFn = strVertexCmpFn // use simple string cmp version
+	}
+	if vertexAddFn == nil {
+		vertexAddFn = func(Vertex) error { return nil } // noop
+	}
+	if vertexRemoveFn == nil {
+		vertexRemoveFn = func(Vertex) error { return nil } // noop
+	}
+	if edgeCmpFn == nil {
+		edgeCmpFn = strEdgeCmpFn // use simple string cmp version
+	}
+
+	var lookup = make(map[Vertex]Vertex)
+	var vertexKeep []Vertex // list of vertices which are the same in new graph
+	var edgeKeep []Edge     // list of vertices which are the same in new graph
+
+	for v := range newGraph.Adjacency() { // loop through the vertices (resources)
+		var vertex Vertex
+		// step one, direct compare with res.Compare
+		if vertex == nil { // redundant guard for consistency
+			fn := func(vv Vertex) (bool, error) {
+				b, err := vertexCmpFn(vv, v)
+				return b, errwrap.Wrapf(err, "vertexCmpFn failed")
+			}
+			var err error
+			vertex, err = oldGraph.VertexMatchFn(fn)
+			if err != nil {
+				return errwrap.Wrapf(err, "VertexMatchFn failed")
+			}
+		}
+
+		// TODO: consider adding a mutate API.
+		// step two, try and mutate with res.Mutate
+		//if vertex == nil { // not found yet...
+		//	vertex = oldGraph.MutateMatch(res)
+		//}
+
+		if vertex == nil { // no match found yet
+			if err := vertexAddFn(v); err != nil {
+				return errwrap.Wrapf(err, "vertexAddFn failed")
+			}
+			vertex = v
+			oldGraph.AddVertex(vertex) // call standalone in case not part of an edge
+		}
+		lookup[v] = vertex                      // used for constructing edges
+		vertexKeep = append(vertexKeep, vertex) // append
+	}
+
+	// get rid of any vertices we shouldn't keep (that aren't in new graph)
+	for v := range oldGraph.Adjacency() {
+		if !VertexContains(v, vertexKeep) {
+			if err := vertexRemoveFn(v); err != nil {
+				return errwrap.Wrapf(err, "vertexRemoveFn failed")
+			}
+			oldGraph.DeleteVertex(v)
+		}
+	}
+
+	// compare edges
+	for v1 := range newGraph.Adjacency() { // loop through the vertices (resources)
+		for v2, e := range newGraph.Adjacency()[v1] {
+			// we have an edge!
+			// lookup vertices (these should exist now)
+			vertex1, exists1 := lookup[v1]
+			vertex2, exists2 := lookup[v2]
+			if !exists1 || !exists2 { // no match found, bug?
+				//if vertex1 == nil || vertex2 == nil { // no match found
+				return fmt.Errorf("new vertices weren't found") // programming error
+			}
+
+			edge, exists := oldGraph.Adjacency()[vertex1][vertex2]
+			if !exists {
+				edge = e // use edge
+			} else if b, err := edgeCmpFn(edge, e); err != nil {
+				return errwrap.Wrapf(err, "edgeCmpFn failed")
+			} else if !b {
+				edge = e // overwrite edge
+			}
+
+			oldGraph.Adjacency()[vertex1][vertex2] = edge // store it (AddEdge)
+			edgeKeep = append(edgeKeep, edge)             // mark as saved
+		}
+	}
+
+	// delete unused edges
+	for v1 := range oldGraph.Adjacency() {
+		for _, e := range oldGraph.Adjacency()[v1] {
+			// we have an edge!
+			if !EdgeContains(e, edgeKeep) {
+				oldGraph.DeleteEdge(e)
+			}
+		}
+	}
+
+	// success
+	*obj = *oldGraph // save old graph
+	return nil
+}

pgraph/graphsync_test.go

@@ -0,0 +1,92 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package pgraph
+
+import (
+	"testing"
+)
+
+func TestGraphSync1(t *testing.T) {
+	g := &Graph{}
+	v1 := NV("v1")
+	v2 := NV("v2")
+	v3 := NV("v3")
+
+	e1 := NE("e1")
+	e2 := NE("e2")
+	g.AddEdge(v1, v3, e1)
+	g.AddEdge(v2, v3, e2)
+
+	// new graph
+	newGraph := &Graph{}
+	v4 := NV("v4")
+	v5 := NV("v5")
+	e3 := NE("e3")
+	newGraph.AddEdge(v4, v5, e3)
+
+	err := g.GraphSync(newGraph, nil, nil, nil, nil)
+	if err != nil {
+		t.Errorf("GraphSync failed: %v", err)
+		return
+	}
+
+	// g should change and become the same
+	if s := runGraphCmp(t, g, newGraph); s != "" {
+		t.Errorf("%s", s)
+	}
+}
+
+func TestGraphSync2(t *testing.T) {
+	v1 := NV("v1")
+	v2 := NV("v2")
+	v3 := NV("v3")
+	v4 := NV("v4")
+	v5 := NV("v5")
+	e1 := NE("e1")
+	e2 := NE("e2")
+	e3 := NE("e3")
+
+	g := &Graph{}
+	g.AddEdge(v1, v3, e1)
+	g.AddEdge(v2, v3, e2)
+
+	// new graph
+	newGraph := &Graph{}
+	newGraph.AddEdge(v1, v3, e1)
+	newGraph.AddEdge(v2, v3, e2)
+	newGraph.AddEdge(v4, v5, e3)
+	//newGraph.AddEdge(v3, v4, NE("v3,v4"))
+	//newGraph.AddEdge(v3, v5, NE("v3,v5"))
+
+	// graphs should differ!
+	if runGraphCmp(t, g, newGraph) == "" {
+		t.Errorf("graphs should differ initially")
+		return
+	}
+
+	err := g.GraphSync(newGraph, strVertexCmpFn, vertexAddFn, vertexRemoveFn, strEdgeCmpFn)
+	if err != nil {
+		t.Errorf("GraphSync failed: %v", err)
+		return
+	}
+
+	// g should change and become the same
+	if s := runGraphCmp(t, g, newGraph); s != "" {
+		t.Errorf("%s", s)
+	}
+}

pgraph/graphviz.go

@@ -1,21 +1,21 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-package pgraph
+package pgraph // TODO: this should be a subpackage
 
 import (
 	"fmt"
@@ -45,12 +45,16 @@ func (g *Graph) Graphviz() (out string) {
 	out += fmt.Sprintf("\tlabel=\"%s\";\n", g.GetName())
 	//out += "\tnode [shape=box];\n"
 	str := ""
-	for i := range g.Adjacency { // reverse paths
-		out += fmt.Sprintf("\t%s [label=\"%s[%s]\"];\n", i.GetName(), i.Kind(), i.GetName())
-		for j := range g.Adjacency[i] {
-			k := g.Adjacency[i][j]
+	for i := range g.Adjacency() { // reverse paths
+		out += fmt.Sprintf("\t\"%s\" [label=\"%s\"];\n", i, i)
+		for j := range g.Adjacency()[i] {
+			k := g.Adjacency()[i][j]
 			// use str for clearer output ordering
-			str += fmt.Sprintf("\t%s -> %s [label=%s];\n", i.GetName(), j.GetName(), k.Name)
+			//if fmtBoldFn(k) { // TODO: add this sort of formatting
+			//	str += fmt.Sprintf("\t\"%s\" -> \"%s\" [label=\"%s\",style=bold];\n", i, j, k)
+			//} else {
+			str += fmt.Sprintf("\t\"%s\" -> \"%s\" [label=\"%s\"];\n", i, j, k)
+			//}
 		}
 	}
 	out += str
@@ -60,16 +64,20 @@ func (g *Graph) Graphviz() (out string) {
 
 // ExecGraphviz writes out the graphviz data and runs the correct graphviz
 // filter command.
-func (g *Graph) ExecGraphviz(program, filename string) error {
+func (g *Graph) ExecGraphviz(program, filename, hostname string) error {
 
 	switch program {
 	case "dot", "neato", "twopi", "circo", "fdp":
 	default:
-		return fmt.Errorf("Invalid graphviz program selected!")
+		return fmt.Errorf("invalid graphviz program selected")
 	}
 
 	if filename == "" {
-		return fmt.Errorf("No filename given!")
+		return fmt.Errorf("no filename given")
+	}
+
+	if hostname != "" {
+		filename = fmt.Sprintf("%s@%s", filename, hostname)
 	}
 
 	// run as a normal user if possible when run with sudo
@@ -78,18 +86,18 @@ func (g *Graph) ExecGraphviz(program, filename string) error {
 
 	err := ioutil.WriteFile(filename, []byte(g.Graphviz()), 0644)
 	if err != nil {
-		return fmt.Errorf("Error writing to filename!")
+		return fmt.Errorf("error writing to filename")
 	}
 
 	if err1 == nil && err2 == nil {
 		if err := os.Chown(filename, uid, gid); err != nil {
-			return fmt.Errorf("Error changing file owner!")
+			return fmt.Errorf("error changing file owner")
 		}
 	}
 
 	path, err := exec.LookPath(program)
 	if err != nil {
-		return fmt.Errorf("Graphviz is missing!")
+		return fmt.Errorf("the Graphviz program is missing")
 	}
 
 	out := fmt.Sprintf("%s.png", filename)
@@ -104,7 +112,7 @@ func (g *Graph) ExecGraphviz(program, filename string) error {
 	}
 	_, err = cmd.Output()
 	if err != nil {
-		return fmt.Errorf("Error writing to image!")
+		return fmt.Errorf("error writing to image")
 	}
 	return nil
 }

pgraph/pgraph.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 // Package pgraph represents the internal "pointer graph" that we use.
@@ -21,30 +21,10 @@ package pgraph
 import (
 	"fmt"
 	"sort"
-	"sync"
-
-	"github.com/purpleidea/mgmt/event"
-	"github.com/purpleidea/mgmt/resources"
 
 	errwrap "github.com/pkg/errors"
 )
 
-//go:generate stringer -type=graphState -output=graphstate_stringer.go
-type graphState int
-
-const (
-	graphStateNil graphState = iota
-	graphStateStarting
-	graphStateStarted
-	graphStatePausing
-	graphStatePaused
-)
-
-// Flags contains specific constants used by the graph.
-type Flags struct {
-	Debug bool
-}
-
 // Graph is the graph structure in this library.
 // The graph abstract data type (ADT) is defined as follows:
 // * the directed graph arrows point from left to right ( -> )
@@ -52,76 +32,72 @@ type Flags struct {
 // * IOW, you might see package -> file -> service (where package runs first)
 // * This is also the direction that the notify should happen in...
 type Graph struct {
-	Name      string
-	Adjacency map[*Vertex]map[*Vertex]*Edge // *Vertex -> *Vertex (edge)
-	Flags     Flags
-	state     graphState
-	mutex     *sync.Mutex // used when modifying graph State variable
-	wg        *sync.WaitGroup
+	Name string
+
+	adjacency map[Vertex]map[Vertex]Edge // Vertex -> Vertex (edge)
+	kv        map[string]interface{}     // some values associated with the graph
 }
 
-// Vertex is the primary vertex struct in this library.
-type Vertex struct {
-	resources.Res       // anonymous field
-	timestamp     int64 // last updated timestamp ?
+// Vertex is the primary vertex struct in this library. It can be anything that
+// implements Stringer. The string output must be stable and unique in a graph.
+type Vertex interface {
+	fmt.Stringer // String() string
 }
 
-// Edge is the primary edge struct in this library.
-type Edge struct {
-	Name   string
-	Notify bool // should we send a refresh notification along this edge?
+// Edge is the primary edge struct in this library. It can be anything that
+// implements Stringer. The string output must be stable and unique in a graph.
+type Edge interface {
+	fmt.Stringer // String() string
+}
 
-	refresh bool // is there a notify pending for the dest vertex ?
+// Init initializes the graph which populates all the internal structures.
+func (g *Graph) Init() error {
+	if g.Name == "" { // FIXME: is this really a good requirement?
+		return fmt.Errorf("can't initialize graph with empty name")
+	}
+
+	//g.adjacency = make(map[Vertex]map[Vertex]Edge) // not required
+	//g.kv = make(map[string]interface{}) // not required
+	return nil
 }
 
 // NewGraph builds a new graph.
-func NewGraph(name string) *Graph {
-	return &Graph{
-		Name:      name,
-		Adjacency: make(map[*Vertex]map[*Vertex]*Edge),
-		state:     graphStateNil,
-		// ptr b/c: Mutex/WaitGroup must not be copied after first use
-		mutex: &sync.Mutex{},
-		wg:    &sync.WaitGroup{},
-	}
-}
-
-// NewVertex returns a new graph vertex struct with a contained resource.
-func NewVertex(r resources.Res) *Vertex {
-	return &Vertex{
-		Res: r,
-	}
-}
-
-// NewEdge returns a new graph edge struct.
-func NewEdge(name string) *Edge {
-	return &Edge{
+func NewGraph(name string) (*Graph, error) {
+	g := &Graph{
 		Name: name,
 	}
+	if err := g.Init(); err != nil {
+		return nil, err
+	}
+	return g, nil
 }
 
-// Refresh returns the pending refresh status of this edge.
-func (obj *Edge) Refresh() bool {
-	return obj.refresh
+// Value returns a value stored alongside the graph in a particular key.
+func (g *Graph) Value(key string) (interface{}, bool) {
+	val, exists := g.kv[key]
+	return val, exists
 }
 
-// SetRefresh sets the pending refresh status of this edge.
-func (obj *Edge) SetRefresh(b bool) {
-	obj.refresh = b
+// SetValue sets a value to be stored alongside the graph in a particular key.
+func (g *Graph) SetValue(key string, val interface{}) {
+	if g.kv == nil { // initialize on first use
+		g.kv = make(map[string]interface{})
+	}
+	g.kv[key] = val
 }
 
-// Copy makes a copy of the graph struct
+// Copy makes a copy of the graph struct.
 func (g *Graph) Copy() *Graph {
+	if g == nil { // allow nil graphs through
+		return g
+	}
 	newGraph := &Graph{
 		Name:      g.Name,
-		Adjacency: make(map[*Vertex]map[*Vertex]*Edge, len(g.Adjacency)),
-		Flags:     g.Flags,
-		state:     g.state,
-		mutex:     g.mutex,
-		wg:        g.wg,
+		adjacency: make(map[Vertex]map[Vertex]Edge, len(g.adjacency)),
+		kv:        g.kv,
 	}
-	for k, v := range g.Adjacency {
-		newGraph.Adjacency[k] = v // copy
+	for k, v := range g.adjacency {
+		newGraph.adjacency[k] = v // copy
 	}
 	return newGraph
 }
@@ -136,76 +112,49 @@ func (g *Graph) SetName(name string) {
 	g.Name = name
 }
 
-// getState returns the state of the graph. This state is used for optimizing
-// certain algorithms by knowing what part of processing the graph is currently
-// undergoing.
-func (g *Graph) getState() graphState {
-	//g.mutex.Lock()
-	//defer g.mutex.Unlock()
-	return g.state
-}
-
-// setState sets the graph state and returns the previous state.
-func (g *Graph) setState(state graphState) graphState {
-	g.mutex.Lock()
-	defer g.mutex.Unlock()
-	prev := g.getState()
-	g.state = state
-	return prev
-}
-
-// AddVertex uses variadic input to add all listed vertices to the graph
-func (g *Graph) AddVertex(xv ...*Vertex) {
+// AddVertex uses variadic input to add all listed vertices to the graph.
+func (g *Graph) AddVertex(xv ...Vertex) {
+	if g.adjacency == nil { // initialize on first use
+		g.adjacency = make(map[Vertex]map[Vertex]Edge)
+	}
 	for _, v := range xv {
-		if _, exists := g.Adjacency[v]; !exists {
-			g.Adjacency[v] = make(map[*Vertex]*Edge)
+		if _, exists := g.adjacency[v]; !exists {
+			g.adjacency[v] = make(map[Vertex]Edge)
 		}
 	}
 }
 
 // DeleteVertex deletes a particular vertex from the graph.
-func (g *Graph) DeleteVertex(v *Vertex) {
-	delete(g.Adjacency, v)
-	for k := range g.Adjacency {
-		delete(g.Adjacency[k], v)
+func (g *Graph) DeleteVertex(v Vertex) {
+	delete(g.adjacency, v)
+	for k := range g.adjacency {
+		delete(g.adjacency[k], v)
 	}
 }
 
 // AddEdge adds a directed edge to the graph from v1 to v2.
-func (g *Graph) AddEdge(v1, v2 *Vertex, e *Edge) {
+func (g *Graph) AddEdge(v1, v2 Vertex, e Edge) {
 	// NOTE: this doesn't allow more than one edge between two vertexes...
 	g.AddVertex(v1, v2) // supports adding N vertices now
 	// TODO: check if an edge exists to avoid overwriting it!
 	// NOTE: VertexMerge() depends on overwriting it at the moment...
-	g.Adjacency[v1][v2] = e
+	g.adjacency[v1][v2] = e
 }
 
 // DeleteEdge deletes a particular edge from the graph.
-// FIXME: add test cases
-func (g *Graph) DeleteEdge(e *Edge) {
-	for v1 := range g.Adjacency {
-		for v2, edge := range g.Adjacency[v1] {
+func (g *Graph) DeleteEdge(e Edge) {
+	for v1 := range g.adjacency {
+		for v2, edge := range g.adjacency[v1] {
 			if e == edge {
-				delete(g.Adjacency[v1], v2)
+				delete(g.adjacency[v1], v2)
 			}
 		}
 	}
 }
 
-// GetVertexMatch searches for an equivalent resource in the graph and returns
-// the vertex it is found in, or nil if not found.
-func (g *Graph) GetVertexMatch(obj resources.Res) *Vertex {
-	for k := range g.Adjacency {
-		if k.Res.Compare(obj) {
-			return k
-		}
-	}
-	return nil
-}
-
 // HasVertex returns if the input vertex exists in the graph.
-func (g *Graph) HasVertex(v *Vertex) bool {
-	if _, exists := g.Adjacency[v]; exists {
+func (g *Graph) HasVertex(v Vertex) bool {
+	if _, exists := g.adjacency[v]; exists {
 		return true
 	}
 	return false
@@ -213,33 +162,40 @@ func (g *Graph) HasVertex(v *Vertex) bool {
 
 // NumVertices returns the number of vertices in the graph.
 func (g *Graph) NumVertices() int {
-	return len(g.Adjacency)
+	return len(g.adjacency)
 }
 
 // NumEdges returns the number of edges in the graph.
 func (g *Graph) NumEdges() int {
 	count := 0
-	for k := range g.Adjacency {
-		count += len(g.Adjacency[k])
+	for k := range g.adjacency {
+		count += len(g.adjacency[k])
 	}
 	return count
 }
 
-// GetVertices returns a randomly sorted slice of all vertices in the graph
+// Adjacency returns the adjacency map representing this graph. This is useful
+// for users who which to operate on the raw data structure more efficiently.
+// This works because maps are reference types so we can edit this at will.
+func (g *Graph) Adjacency() map[Vertex]map[Vertex]Edge {
+	return g.adjacency
+}
+
+// Vertices returns a randomly sorted slice of all vertices in the graph.
 // The order is random, because the map implementation is intentionally so!
-func (g *Graph) GetVertices() []*Vertex {
-	var vertices []*Vertex
-	for k := range g.Adjacency {
+func (g *Graph) Vertices() []Vertex {
+	var vertices []Vertex
+	for k := range g.adjacency {
 		vertices = append(vertices, k)
 	}
 	return vertices
 }
 
-// GetVerticesChan returns a channel of all vertices in the graph.
-func (g *Graph) GetVerticesChan() chan *Vertex {
-	ch := make(chan *Vertex)
-	go func(ch chan *Vertex) {
-		for k := range g.Adjacency {
+// VerticesChan returns a channel of all vertices in the graph.
+func (g *Graph) VerticesChan() chan Vertex {
+	ch := make(chan Vertex)
+	go func(ch chan Vertex) {
+		for k := range g.adjacency {
 			ch <- k
 		}
 		close(ch)
@@ -248,17 +204,17 @@ func (g *Graph) GetVerticesChan() chan *Vertex {
 }
 
 // VertexSlice is a linear list of vertices. It can be sorted.
-type VertexSlice []*Vertex
+type VertexSlice []Vertex
 
 func (vs VertexSlice) Len() int           { return len(vs) }
 func (vs VertexSlice) Swap(i, j int)      { vs[i], vs[j] = vs[j], vs[i] }
 func (vs VertexSlice) Less(i, j int) bool { return vs[i].String() < vs[j].String() }
 
-// GetVerticesSorted returns a sorted slice of all vertices in the graph
-// The order is sorted by String() to avoid the non-determinism in the map type
-func (g *Graph) GetVerticesSorted() []*Vertex {
-	var vertices []*Vertex
-	for k := range g.Adjacency {
+// VerticesSorted returns a sorted slice of all vertices in the graph.
+// The order is sorted by String() to avoid the non-determinism in the map type.
+func (g *Graph) VerticesSorted() []Vertex {
+	var vertices []Vertex
+	for k := range g.adjacency {
 		vertices = append(vertices, k)
 	}
 	sort.Sort(VertexSlice(vertices)) // add determinism
@@ -270,19 +226,14 @@ func (g *Graph) String() string {
 	return fmt.Sprintf("Vertices(%d), Edges(%d)", g.NumVertices(), g.NumEdges())
 }
 
-// String returns the canonical form for a vertex
-func (v *Vertex) String() string {
-	return fmt.Sprintf("%s[%s]", v.Res.Kind(), v.Res.GetName())
-}
-
 // IncomingGraphVertices returns an array (slice) of all directed vertices to
 // vertex v (??? -> v). OKTimestamp should probably use this.
-func (g *Graph) IncomingGraphVertices(v *Vertex) []*Vertex {
+func (g *Graph) IncomingGraphVertices(v Vertex) []Vertex {
 	// TODO: we might be able to implement this differently by reversing
 	// the Adjacency graph and then looping through it again...
-	var s []*Vertex
-	for k := range g.Adjacency { // reverse paths
-		for w := range g.Adjacency[k] {
+	var s []Vertex
+	for k := range g.adjacency { // reverse paths
+		for w := range g.adjacency[k] {
 			if w == v {
 				s = append(s, k)
 			}
@@ -293,9 +244,9 @@ func (g *Graph) IncomingGraphVertices(v *Vertex) []*Vertex {
 
 // OutgoingGraphVertices returns an array (slice) of all vertices that vertex v
 // points to (v -> ???). Poke should probably use this.
-func (g *Graph) OutgoingGraphVertices(v *Vertex) []*Vertex {
-	var s []*Vertex
-	for k := range g.Adjacency[v] { // forward paths
+func (g *Graph) OutgoingGraphVertices(v Vertex) []Vertex {
+	var s []Vertex
+	for k := range g.adjacency[v] { // forward paths
 		s = append(s, k)
 	}
 	return s
@@ -303,18 +254,18 @@ func (g *Graph) OutgoingGraphVertices(v *Vertex) []*Vertex {
 
 // GraphVertices returns an array (slice) of all vertices that connect to vertex v.
 // This is the union of IncomingGraphVertices and OutgoingGraphVertices.
-func (g *Graph) GraphVertices(v *Vertex) []*Vertex {
-	var s []*Vertex
+func (g *Graph) GraphVertices(v Vertex) []Vertex {
+	var s []Vertex
 	s = append(s, g.IncomingGraphVertices(v)...)
 	s = append(s, g.OutgoingGraphVertices(v)...)
 	return s
 }
 
 // IncomingGraphEdges returns all of the edges that point to vertex v (??? -> v).
-func (g *Graph) IncomingGraphEdges(v *Vertex) []*Edge {
-	var edges []*Edge
-	for v1 := range g.Adjacency { // reverse paths
-		for v2, e := range g.Adjacency[v1] {
+func (g *Graph) IncomingGraphEdges(v Vertex) []Edge {
+	var edges []Edge
+	for v1 := range g.adjacency { // reverse paths
+		for v2, e := range g.adjacency[v1] {
 			if v2 == v {
 				edges = append(edges, e)
 			}
@@ -324,9 +275,9 @@ func (g *Graph) IncomingGraphEdges(v *Vertex) []*Edge {
 }
 
 // OutgoingGraphEdges returns all of the edges that point from vertex v (v -> ???).
-func (g *Graph) OutgoingGraphEdges(v *Vertex) []*Edge {
-	var edges []*Edge
-	for _, e := range g.Adjacency[v] { // forward paths
+func (g *Graph) OutgoingGraphEdges(v Vertex) []Edge {
+	var edges []Edge
+	for _, e := range g.adjacency[v] { // forward paths
 		edges = append(edges, e)
 	}
 	return edges
@@ -334,18 +285,18 @@ func (g *Graph) OutgoingGraphEdges(v *Vertex) []*Edge {
 
 // GraphEdges returns an array (slice) of all edges that connect to vertex v.
 // This is the union of IncomingGraphEdges and OutgoingGraphEdges.
-func (g *Graph) GraphEdges(v *Vertex) []*Edge {
-	var edges []*Edge
+func (g *Graph) GraphEdges(v Vertex) []Edge {
+	var edges []Edge
 	edges = append(edges, g.IncomingGraphEdges(v)...)
 	edges = append(edges, g.OutgoingGraphEdges(v)...)
 	return edges
 }
 
 // DFS returns a depth first search for the graph, starting at the input vertex.
-func (g *Graph) DFS(start *Vertex) []*Vertex {
-	var d []*Vertex // discovered
-	var s []*Vertex // stack
-	if _, exists := g.Adjacency[start]; !exists {
+func (g *Graph) DFS(start Vertex) []Vertex {
+	var d []Vertex // discovered
+	var s []Vertex // stack
+	if _, exists := g.adjacency[start]; !exists {
 		return nil // TODO: error
 	}
 	v := start
@@ -365,64 +316,65 @@ func (g *Graph) DFS(start *Vertex) []*Vertex {
 }
 
 // FilterGraph builds a new graph containing only vertices from the list.
-func (g *Graph) FilterGraph(name string, vertices []*Vertex) *Graph {
-	newgraph := NewGraph(name)
-	for k1, x := range g.Adjacency {
+func (g *Graph) FilterGraph(name string, vertices []Vertex) (*Graph, error) {
+	newGraph := &Graph{Name: name}
+	if err := newGraph.Init(); err != nil {
+		return nil, errwrap.Wrapf(err, "could not run FilterGraph() properly")
+	}
+	for k1, x := range g.adjacency {
 		for k2, e := range x {
 			//log.Printf("Filter: %s -> %s # %s", k1.Name, k2.Name, e.Name)
 			if VertexContains(k1, vertices) || VertexContains(k2, vertices) {
-				newgraph.AddEdge(k1, k2, e)
+				newGraph.AddEdge(k1, k2, e)
 			}
 		}
 	}
-	return newgraph
+	return newGraph, nil
 }
 
-// GetDisconnectedGraphs returns a channel containing the N disconnected graphs
-// in our main graph. We can then process each of these in parallel.
-func (g *Graph) GetDisconnectedGraphs() chan *Graph {
-	ch := make(chan *Graph)
-	go func() {
-		var start *Vertex
-		var d []*Vertex // discovered
-		c := g.NumVertices()
-		for len(d) < c {
+// DisconnectedGraphs returns a list containing the N disconnected graphs.
+func (g *Graph) DisconnectedGraphs() ([]*Graph, error) {
+	graphs := []*Graph{}
+	var start Vertex
+	var d []Vertex // discovered
+	c := g.NumVertices()
+	for len(d) < c {
 
-			// get an undiscovered vertex to start from
-			for _, s := range g.GetVertices() {
-				if !VertexContains(s, d) {
-					start = s
-				}
+		// get an undiscovered vertex to start from
+		for _, s := range g.Vertices() {
+			if !VertexContains(s, d) {
+				start = s
 			}
-
-			// dfs through the graph
-			dfs := g.DFS(start)
-			// filter all the collected elements into a new graph
-			newgraph := g.FilterGraph(g.Name, dfs)
-
-			// add number of elements found to found variable
-			d = append(d, dfs...) // extend
-
-			// return this new graph to the channel
-			ch <- newgraph
-
-			// if we've found all the elements, then we're done
-			// otherwise loop through to continue...
 		}
-		close(ch)
-	}()
-	return ch
+
+		// dfs through the graph
+		dfs := g.DFS(start)
+		// filter all the collected elements into a new graph
+		newgraph, err := g.FilterGraph(g.Name, dfs)
+		if err != nil {
+			return nil, errwrap.Wrapf(err, "could not run DisconnectedGraphs() properly")
+		}
+		// add number of elements found to found variable
+		d = append(d, dfs...) // extend
+
+		// append this new graph to the list
+		graphs = append(graphs, newgraph)
+
+		// if we've found all the elements, then we're done
+		// otherwise loop through to continue...
+	}
+	return graphs, nil
 }
 
 // InDegree returns the count of vertices that point to me in one big lookup map.
-func (g *Graph) InDegree() map[*Vertex]int {
-	result := make(map[*Vertex]int)
-	for k := range g.Adjacency {
+func (g *Graph) InDegree() map[Vertex]int {
+	result := make(map[Vertex]int)
+	for k := range g.adjacency {
 		result[k] = 0 // initialize
 	}
 
-	for k := range g.Adjacency {
-		for z := range g.Adjacency[k] {
+	for k := range g.adjacency {
+		for z := range g.adjacency[k] {
 			result[z]++
 		}
 	}
@@ -430,12 +382,12 @@ func (g *Graph) InDegree() map[*Vertex]int {
 }
 
 // OutDegree returns the count of vertices that point away in one big lookup map.
-func (g *Graph) OutDegree() map[*Vertex]int {
-	result := make(map[*Vertex]int)
+func (g *Graph) OutDegree() map[Vertex]int {
+	result := make(map[Vertex]int)
 
-	for k := range g.Adjacency {
+	for k := range g.adjacency {
 		result[k] = 0 // initialize
-		for range g.Adjacency[k] {
+		for range g.adjacency[k] {
 			result[k]++
 		}
 	}
@@ -443,12 +395,12 @@ func (g *Graph) OutDegree() map[*Vertex]int {
 }
 
 // TopologicalSort returns the sort of graph vertices in that order.
-// based on descriptions and code from wikipedia and rosetta code
+// It is based on descriptions and code from wikipedia and rosetta code.
 // TODO: add memoization, and cache invalidation to speed this up :)
-func (g *Graph) TopologicalSort() ([]*Vertex, error) { // kahn's algorithm
-	var L []*Vertex                    // empty list that will contain the sorted elements
-	var S []*Vertex                    // set of all nodes with no incoming edges
-	remaining := make(map[*Vertex]int) // amount of edges remaining
+func (g *Graph) TopologicalSort() ([]Vertex, error) { // kahn's algorithm
+	var L []Vertex                    // empty list that will contain the sorted elements
+	var S []Vertex                    // set of all nodes with no incoming edges
+	remaining := make(map[Vertex]int) // amount of edges remaining
 
 	for v, d := range g.InDegree() {
 		if d == 0 {
@@ -465,7 +417,7 @@ func (g *Graph) TopologicalSort() ([]*Vertex, error) { // kahn's algorithm
 		v := S[last]
 		S = S[:last]
 		L = append(L, v) // add v to tail of L
-		for n := range g.Adjacency[v] {
+		for n := range g.adjacency[v] {
 			// for each node n remaining in the graph, consume from
 			// remaining, so for remaining[n] > 0
 			if remaining[n] > 0 {
@@ -480,9 +432,9 @@ func (g *Graph) TopologicalSort() ([]*Vertex, error) { // kahn's algorithm
 	// if graph has edges, eg if any value in rem is > 0
 	for c, in := range remaining {
 		if in > 0 {
-			for n := range g.Adjacency[c] {
+			for n := range g.adjacency[c] {
 				if remaining[n] > 0 {
-					return nil, fmt.Errorf("Not a dag!")
+					return nil, fmt.Errorf("not a dag")
 				}
 			}
 		}
@@ -499,19 +451,19 @@ func (g *Graph) TopologicalSort() ([]*Vertex, error) { // kahn's algorithm
 // actually return a tree if we cared about correctness.
 // This operates by a recursive algorithm; a more efficient version is likely.
 // If you don't give this function a DAG, you might cause infinite recursion!
-func (g *Graph) Reachability(a, b *Vertex) []*Vertex {
+func (g *Graph) Reachability(a, b Vertex) []Vertex {
 	if a == nil || b == nil {
 		return nil
 	}
 	vertices := g.OutgoingGraphVertices(a) // what points away from a ?
 	if len(vertices) == 0 {
-		return []*Vertex{} // nope
+		return []Vertex{} // nope
 	}
 	if VertexContains(b, vertices) {
-		return []*Vertex{a, b} // found
+		return []Vertex{a, b} // found
 	}
 	// TODO: parallelize this with go routines?
-	var collected = make([][]*Vertex, len(vertices))
+	var collected = make([][]Vertex, len(vertices))
 	pick := -1
 	for i, v := range vertices {
 		collected[i] = g.Reachability(v, b) // find b by recursion
@@ -524,110 +476,111 @@ func (g *Graph) Reachability(a, b *Vertex) []*Vertex {
 		}
 	}
 	if pick < 0 {
-		return []*Vertex{} // nope
+		return []Vertex{} // nope
 	}
-	result := []*Vertex{a} // tack on a
+	result := []Vertex{a} // tack on a
 	result = append(result, collected[pick]...)
 	return result
 }
 
-// GraphSync updates the oldGraph so that it matches the newGraph receiver. It
-// leaves identical elements alone so that they don't need to be refreshed.
-// FIXME: add test cases
-func (g *Graph) GraphSync(oldGraph *Graph) (*Graph, error) {
-
-	if oldGraph == nil {
-		oldGraph = NewGraph(g.GetName()) // copy over the name
-	}
-	oldGraph.SetName(g.GetName()) // overwrite the name
-
-	var lookup = make(map[*Vertex]*Vertex)
-	var vertexKeep []*Vertex // list of vertices which are the same in new graph
-	var edgeKeep []*Edge     // list of vertices which are the same in new graph
-
-	for v := range g.Adjacency { // loop through the vertices (resources)
-		res := v.Res // resource
-
-		vertex := oldGraph.GetVertexMatch(res)
-		if vertex == nil { // no match found
-			if err := res.Init(); err != nil {
-				return nil, errwrap.Wrapf(err, "could not Init() resource")
-			}
-			vertex = NewVertex(res)
-			oldGraph.AddVertex(vertex) // call standalone in case not part of an edge
-		}
-		lookup[v] = vertex                      // used for constructing edges
-		vertexKeep = append(vertexKeep, vertex) // append
-	}
-
-	// get rid of any vertices we shouldn't keep (that aren't in new graph)
-	for v := range oldGraph.Adjacency {
-		if !VertexContains(v, vertexKeep) {
-			// wait for exit before starting new graph!
-			v.SendEvent(event.EventExit, true, false)
-			oldGraph.DeleteVertex(v)
+// VertexMatchFn searches for a vertex in the graph and returns the vertex if
+// one matches. It uses a user defined function to match. That function must
+// return true on match, and an error if anything goes wrong.
+func (g *Graph) VertexMatchFn(fn func(Vertex) (bool, error)) (Vertex, error) {
+	for v := range g.adjacency {
+		if b, err := fn(v); err != nil {
+			return nil, errwrap.Wrapf(err, "fn in VertexMatchFn() errored")
+		} else if b {
+			return v, nil
 		}
 	}
-
-	// compare edges
-	for v1 := range g.Adjacency { // loop through the vertices (resources)
-		for v2, e := range g.Adjacency[v1] {
-			// we have an edge!
-
-			// lookup vertices (these should exist now)
-			//res1 := v1.Res // resource
-			//res2 := v2.Res
-			//vertex1 := oldGraph.GetVertexMatch(res1)
-			//vertex2 := oldGraph.GetVertexMatch(res2)
-			vertex1, exists1 := lookup[v1]
-			vertex2, exists2 := lookup[v2]
-			if !exists1 || !exists2 { // no match found, bug?
-				//if vertex1 == nil || vertex2 == nil { // no match found
-				return nil, fmt.Errorf("New vertices weren't found!") // programming error
-			}
-
-			edge, exists := oldGraph.Adjacency[vertex1][vertex2]
-			if !exists || edge.Name != e.Name { // TODO: edgeCmp
-				edge = e // use or overwrite edge
-			}
-			oldGraph.Adjacency[vertex1][vertex2] = edge // store it (AddEdge)
-			edgeKeep = append(edgeKeep, edge)           // mark as saved
-		}
-	}
-
-	// delete unused edges
-	for v1 := range oldGraph.Adjacency {
-		for _, e := range oldGraph.Adjacency[v1] {
-			// we have an edge!
-			if !EdgeContains(e, edgeKeep) {
-				oldGraph.DeleteEdge(e)
-			}
-		}
-	}
-
-	return oldGraph, nil
+	return nil, nil // nothing found
 }
 
-// GraphMetas returns a list of pointers to each of the resource MetaParams.
-func (g *Graph) GraphMetas() []*resources.MetaParams {
-	metas := []*resources.MetaParams{}
-	for v := range g.Adjacency { // loop through the vertices (resources))
-		res := v.Res // resource
-		meta := res.Meta()
-		metas = append(metas, meta)
+// GraphCmp compares the topology of this graph to another and returns nil if
+// they're equal. It uses a user defined function to compare topologically
+// equivalent vertices, and edges.
+// FIXME: add more test cases
+func (g *Graph) GraphCmp(graph *Graph, vertexCmpFn func(Vertex, Vertex) (bool, error), edgeCmpFn func(Edge, Edge) (bool, error)) error {
+	n1, n2 := g.NumVertices(), graph.NumVertices()
+	if n1 != n2 {
+		return fmt.Errorf("base graph has %d vertices, while input graph has %d", n1, n2)
+	}
+	if e1, e2 := g.NumEdges(), graph.NumEdges(); e1 != e2 {
+		return fmt.Errorf("base graph has %d edges, while input graph has %d", e1, e2)
 	}
-	return metas
-}
 
-// AssociateData associates some data with the object in the graph in question.
-func (g *Graph) AssociateData(data *resources.Data) {
-	for k := range g.Adjacency {
-		k.Res.AssociateData(data)
+	var m = make(map[Vertex]Vertex) // g to graph vertex correspondence
+Loop:
+	// check vertices
+	for v1 := range g.Adjacency() { // for each vertex in g
+		for v2 := range graph.Adjacency() { // does it match in graph ?
+			b, err := vertexCmpFn(v1, v2)
+			if err != nil {
+				return errwrap.Wrapf(err, "could not run vertexCmpFn() properly")
+			}
+			// does it match ?
+			if b {
+				m[v1] = v2 // store the mapping
+				continue Loop
+			}
+		}
+		return fmt.Errorf("base graph, has no match in input graph for: %s", v1)
 	}
+	// vertices match :)
+
+	// is the mapping the right length?
+	if n1 := len(m); n1 != n2 {
+		return fmt.Errorf("mapping only has correspondence of %d, when it should have %d", n1, n2)
+	}
+
+	// check if mapping is unique (are there duplicates?)
+	m1 := []Vertex{}
+	m2 := []Vertex{}
+	for k, v := range m {
+		if VertexContains(k, m1) {
+			return fmt.Errorf("mapping from %s is used more than once to: %s", k, m1)
+		}
+		if VertexContains(v, m2) {
+			return fmt.Errorf("mapping to %s is used more than once from: %s", v, m2)
+		}
+		m1 = append(m1, k)
+		m2 = append(m2, v)
+	}
+
+	// check edges
+	for v1 := range g.Adjacency() { // for each vertex in g
+		v2 := m[v1] // lookup in map to get correspondance
+		// g.Adjacency()[v1] corresponds to graph.Adjacency()[v2]
+		if e1, e2 := len(g.Adjacency()[v1]), len(graph.Adjacency()[v2]); e1 != e2 {
+			return fmt.Errorf("base graph, vertex(%s) has %d edges, while input graph, vertex(%s) has %d", v1, e1, v2, e2)
+		}
+
+		for vv1, ee1 := range g.Adjacency()[v1] {
+			vv2 := m[vv1]
+			ee2 := graph.Adjacency()[v2][vv2]
+
+			// these are edges from v1 -> vv1 via ee1 (graph 1)
+			// to cmp to edges from v2 -> vv2 via ee2 (graph 2)
+
+			// check: (1) vv1 == vv2 ? (we've already checked this!)
+
+			// check: (2) ee1 == ee2
+			b, err := edgeCmpFn(ee1, ee2)
+			if err != nil {
+				return errwrap.Wrapf(err, "could not run edgeCmpFn() properly")
+			}
+			if !b {
+				return fmt.Errorf("base graph edge(%s) doesn't match input graph edge(%s)", ee1, ee2)
+			}
+		}
+	}
+
+	return nil // success!
 }
 
 // VertexContains is an "in array" function to test for a vertex in a slice of vertices.
-func VertexContains(needle *Vertex, haystack []*Vertex) bool {
+func VertexContains(needle Vertex, haystack []Vertex) bool {
 	for _, v := range haystack {
 		if needle == v {
 			return true
@@ -637,7 +590,7 @@ func VertexContains(needle *Vertex, haystack []*Vertex) bool {
 }
 
 // EdgeContains is an "in array" function to test for an edge in a slice of edges.
-func EdgeContains(needle *Edge, haystack []*Edge) bool {
+func EdgeContains(needle Edge, haystack []Edge) bool {
 	for _, v := range haystack {
 		if needle == v {
 			return true
@@ -647,12 +600,23 @@ func EdgeContains(needle *Edge, haystack []*Edge) bool {
 }
 
 // Reverse reverses a list of vertices.
-func Reverse(vs []*Vertex) []*Vertex {
-	//var out []*Vertex       // XXX: golint suggests, but it fails testing
-	out := make([]*Vertex, 0) // empty list
+func Reverse(vs []Vertex) []Vertex {
+	out := []Vertex{}
 	l := len(vs)
 	for i := range vs {
 		out = append(out, vs[l-i-1])
 	}
 	return out
 }
+
+// Sort the list of vertices and return a copy without modifying the input.
+func Sort(vs []Vertex) []Vertex {
+	vertices := []Vertex{}
+	for _, v := range vs { // copy
+		vertices = append(vertices, v)
+	}
+	sort.Sort(VertexSlice(vertices))
+	return vertices
+	// sort.Sort(VertexSlice(vs)) // this is wrong, it would modify input!
+	//return vs
+}

pgraph/subgraph.go

@@ -0,0 +1,106 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package pgraph
+
+// AddGraph adds the set of edges and vertices of a graph to the existing graph.
+func (g *Graph) AddGraph(graph *Graph) {
+	g.addEdgeVertexGraphHelper(nil, graph, nil, false, false)
+}
+
+// AddEdgeVertexGraph adds a directed edge to the graph from a vertex.
+// This is useful for flattening the relationship between a subgraph and an
+// existing graph, without having to run the subgraph recursively. It adds the
+// maximum number of edges, creating a relationship to every vertex.
+func (g *Graph) AddEdgeVertexGraph(vertex Vertex, graph *Graph, edgeGenFn func(v1, v2 Vertex) Edge) {
+	g.addEdgeVertexGraphHelper(vertex, graph, edgeGenFn, false, false)
+}
+
+// AddEdgeVertexGraphLight adds a directed edge to the graph from a vertex.
+// This is useful for flattening the relationship between a subgraph and an
+// existing graph, without having to run the subgraph recursively. It adds the
+// minimum number of edges, creating a relationship to the vertices with
+// indegree equal to zero.
+func (g *Graph) AddEdgeVertexGraphLight(vertex Vertex, graph *Graph, edgeGenFn func(v1, v2 Vertex) Edge) {
+	g.addEdgeVertexGraphHelper(vertex, graph, edgeGenFn, false, true)
+}
+
+// AddEdgeGraphVertex adds a directed edge to the vertex from a graph.
+// This is useful for flattening the relationship between a subgraph and an
+// existing graph, without having to run the subgraph recursively. It adds the
+// maximum number of edges, creating a relationship from every vertex.
+func (g *Graph) AddEdgeGraphVertex(graph *Graph, vertex Vertex, edgeGenFn func(v1, v2 Vertex) Edge) {
+	g.addEdgeVertexGraphHelper(vertex, graph, edgeGenFn, true, false)
+}
+
+// AddEdgeGraphVertexLight adds a directed edge to the vertex from a graph.
+// This is useful for flattening the relationship between a subgraph and an
+// existing graph, without having to run the subgraph recursively. It adds the
+// minimum number of edges, creating a relationship from the vertices with
+// outdegree equal to zero.
+func (g *Graph) AddEdgeGraphVertexLight(graph *Graph, vertex Vertex, edgeGenFn func(v1, v2 Vertex) Edge) {
+	g.addEdgeVertexGraphHelper(vertex, graph, edgeGenFn, true, true)
+}
+
+// addEdgeVertexGraphHelper is a helper function to add a directed edges to the
+// graph from a vertex, or vice-versa. It operates in this reverse direction by
+// specifying the reverse argument as true. It is useful for flattening the
+// relationship between a subgraph and an existing graph, without having to run
+// the subgraph recursively. It adds the maximum number of edges, creating a
+// relationship to or from every vertex if the light argument is false, and if
+// it is true, it adds the minimum number of edges, creating a relationship to
+// or from the vertices with an indegree or outdegree equal to zero depending on
+// if we specified reverse or not.
+func (g *Graph) addEdgeVertexGraphHelper(vertex Vertex, graph *Graph, edgeGenFn func(v1, v2 Vertex) Edge, reverse, light bool) {
+
+	var degree map[Vertex]int // compute all of the in/outdegree's if needed
+	if light && reverse {
+		degree = graph.OutDegree()
+	} else if light { // && !reverse
+		degree = graph.InDegree()
+	}
+	for _, v := range graph.VerticesSorted() { // sort to help out edgeGenFn
+
+		// forward:
+		// we only want to add edges to indegree == 0, because every
+		// other vertex is a dependency of at least one of those
+
+		// reverse:
+		// we only want to add edges to outdegree == 0, because every
+		// other vertex is a pre-requisite to at least one of these
+		if light && degree[v] != 0 {
+			continue
+		}
+
+		g.AddVertex(v) // ensure vertex is part of the graph
+
+		if vertex != nil && reverse {
+			edge := edgeGenFn(v, vertex) // generate a new unique edge
+			g.AddEdge(v, vertex, edge)
+		} else if vertex != nil { // && !reverse
+			edge := edgeGenFn(vertex, v)
+			g.AddEdge(vertex, v, edge)
+		}
+	}
+
+	// also remember to suck in all of the graph's edges too!
+	for v1 := range graph.Adjacency() {
+		for v2, e := range graph.Adjacency()[v1] {
+			g.AddEdge(v1, v2, e)
+		}
+	}
+}

pgraph/subgraph_test.go

@@ -0,0 +1,187 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package pgraph
+
+import (
+	"testing"
+)
+
+func TestAddEdgeGraph1(t *testing.T) {
+	v1 := NV("v1")
+	v2 := NV("v2")
+	v3 := NV("v3")
+	v4 := NV("v4")
+	v5 := NV("v5")
+	e1 := NE("e1")
+	e2 := NE("e2")
+	e3 := NE("e3")
+
+	g := &Graph{}
+	g.AddEdge(v1, v3, e1)
+	g.AddEdge(v2, v3, e2)
+
+	sub := &Graph{}
+	sub.AddEdge(v4, v5, e3)
+
+	g.AddGraph(sub)
+
+	// expected (can re-use the same vertices)
+	expected := &Graph{}
+	expected.AddEdge(v1, v3, e1)
+	expected.AddEdge(v2, v3, e2)
+	expected.AddEdge(v4, v5, e3)
+
+	//expected.AddEdge(v3, v4, NE("v3,v4"))
+	//expected.AddEdge(v3, v5, NE("v3,v5"))
+
+	if s := runGraphCmp(t, g, expected); s != "" {
+		t.Errorf("%s", s)
+	}
+}
+
+func TestAddEdgeVertexGraph1(t *testing.T) {
+	v1 := NV("v1")
+	v2 := NV("v2")
+	v3 := NV("v3")
+	v4 := NV("v4")
+	v5 := NV("v5")
+	e1 := NE("e1")
+	e2 := NE("e2")
+	e3 := NE("e3")
+
+	g := &Graph{}
+	g.AddEdge(v1, v3, e1)
+	g.AddEdge(v2, v3, e2)
+
+	sub := &Graph{}
+	sub.AddEdge(v4, v5, e3)
+
+	g.AddEdgeVertexGraph(v3, sub, edgeGenFn)
+
+	// expected (can re-use the same vertices)
+	expected := &Graph{}
+	expected.AddEdge(v1, v3, e1)
+	expected.AddEdge(v2, v3, e2)
+	expected.AddEdge(v4, v5, e3)
+
+	expected.AddEdge(v3, v4, NE("v3,v4"))
+	expected.AddEdge(v3, v5, NE("v3,v5"))
+
+	if s := runGraphCmp(t, g, expected); s != "" {
+		t.Errorf("%s", s)
+	}
+}
+
+func TestAddEdgeGraphVertex1(t *testing.T) {
+	v1 := NV("v1")
+	v2 := NV("v2")
+	v3 := NV("v3")
+	v4 := NV("v4")
+	v5 := NV("v5")
+	e1 := NE("e1")
+	e2 := NE("e2")
+	e3 := NE("e3")
+
+	g := &Graph{}
+	g.AddEdge(v1, v3, e1)
+	g.AddEdge(v2, v3, e2)
+
+	sub := &Graph{}
+	sub.AddEdge(v4, v5, e3)
+
+	g.AddEdgeGraphVertex(sub, v3, edgeGenFn)
+
+	// expected (can re-use the same vertices)
+	expected := &Graph{}
+	expected.AddEdge(v1, v3, e1)
+	expected.AddEdge(v2, v3, e2)
+	expected.AddEdge(v4, v5, e3)
+
+	expected.AddEdge(v4, v3, NE("v4,v3"))
+	expected.AddEdge(v5, v3, NE("v5,v3"))
+
+	if s := runGraphCmp(t, g, expected); s != "" {
+		t.Errorf("%s", s)
+	}
+}
+
+func TestAddEdgeVertexGraphLight1(t *testing.T) {
+	v1 := NV("v1")
+	v2 := NV("v2")
+	v3 := NV("v3")
+	v4 := NV("v4")
+	v5 := NV("v5")
+	e1 := NE("e1")
+	e2 := NE("e2")
+	e3 := NE("e3")
+
+	g := &Graph{}
+	g.AddEdge(v1, v3, e1)
+	g.AddEdge(v2, v3, e2)
+
+	sub := &Graph{}
+	sub.AddEdge(v4, v5, e3)
+
+	g.AddEdgeVertexGraphLight(v3, sub, edgeGenFn)
+
+	// expected (can re-use the same vertices)
+	expected := &Graph{}
+	expected.AddEdge(v1, v3, e1)
+	expected.AddEdge(v2, v3, e2)
+	expected.AddEdge(v4, v5, e3)
+
+	expected.AddEdge(v3, v4, NE("v3,v4"))
+	//expected.AddEdge(v3, v5, NE("v3,v5")) // not needed with light
+
+	if s := runGraphCmp(t, g, expected); s != "" {
+		t.Errorf("%s", s)
+	}
+}
+
+func TestAddEdgeGraphVertexLight1(t *testing.T) {
+	v1 := NV("v1")
+	v2 := NV("v2")
+	v3 := NV("v3")
+	v4 := NV("v4")
+	v5 := NV("v5")
+	e1 := NE("e1")
+	e2 := NE("e2")
+	e3 := NE("e3")
+
+	g := &Graph{}
+	g.AddEdge(v1, v3, e1)
+	g.AddEdge(v2, v3, e2)
+
+	sub := &Graph{}
+	sub.AddEdge(v4, v5, e3)
+
+	g.AddEdgeGraphVertexLight(sub, v3, edgeGenFn)
+
+	// expected (can re-use the same vertices)
+	expected := &Graph{}
+	expected.AddEdge(v1, v3, e1)
+	expected.AddEdge(v2, v3, e2)
+	expected.AddEdge(v4, v5, e3)
+
+	//expected.AddEdge(v4, v3, NE("v4,v3")) // not needed with light
+	expected.AddEdge(v5, v3, NE("v5,v3"))
+
+	if s := runGraphCmp(t, g, expected); s != "" {
+		t.Errorf("%s", s)
+	}
+}

pgraph/util_test.go

@@ -0,0 +1,93 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package pgraph
+
+import (
+	"fmt"
+	"testing"
+)
+
+// vertex is a test struct to test the library.
+type vertex struct {
+	name string
+}
+
+// String is a required method of the Vertex interface that we must fulfill.
+func (v *vertex) String() string {
+	return v.name
+}
+
+// NV is a helper function to make testing easier. It creates a new noop vertex.
+func NV(s string) Vertex {
+	return &vertex{s}
+}
+
+// edge is a test struct to test the library.
+type edge struct {
+	name string
+}
+
+// String is a required method of the Edge interface that we must fulfill.
+func (e *edge) String() string {
+	return e.name
+}
+
+// NE is a helper function to make testing easier. It creates a new noop edge.
+func NE(s string) Edge {
+	return &edge{s}
+}
+
+// edgeGenFn generates unique edges for each vertex pair, assuming unique
+// vertices.
+func edgeGenFn(v1, v2 Vertex) Edge {
+	return NE(fmt.Sprintf("%s,%s", v1, v2))
+}
+
+func vertexAddFn(v Vertex) error {
+	return nil
+}
+
+func vertexRemoveFn(v Vertex) error {
+	return nil
+}
+
+func runGraphCmp(t *testing.T, g1, g2 *Graph) string {
+	err := g1.GraphCmp(g2, strVertexCmpFn, strEdgeCmpFn)
+	if err != nil {
+		str := ""
+		str += fmt.Sprintf("  actual (g1): %v%s", g1, fullPrint(g1))
+		str += fmt.Sprintf("expected (g2): %v%s", g2, fullPrint(g2))
+		str += fmt.Sprintf("cmp error:")
+		str += fmt.Sprintf("%v", err)
+		return str
+	}
+	return ""
+}
+
+func fullPrint(g *Graph) (str string) {
+	str += "\n"
+	for v := range g.Adjacency() {
+		str += fmt.Sprintf("* v: %s\n", v)
+	}
+	for v1 := range g.Adjacency() {
+		for v2, e := range g.Adjacency()[v1] {
+			str += fmt.Sprintf("* e: %s -> %s # %s\n", v1, v2, e)
+		}
+	}
+	return
+}

prometheus/prometheus.go

@@ -0,0 +1,263 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+// Package prometheus provides functions that are useful to control and manage
+// the build-in prometheus instance.
+package prometheus
+
+import (
+	"errors"
+	"net/http"
+	"strconv"
+	"sync"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+
+	errwrap "github.com/pkg/errors"
+)
+
+// DefaultPrometheusListen is registered in
+// https://github.com/prometheus/prometheus/wiki/Default-port-allocations
+const DefaultPrometheusListen = "127.0.0.1:9233"
+
+// ResState represents the status of a resource.
+type ResState int
+
+const (
+	// ResStateOK represents a working resource
+	ResStateOK ResState = iota
+	// ResStateSoftFail represents a resource in soft fail (will be retried)
+	ResStateSoftFail
+	// ResStateHardFail represents a resource in hard fail (will NOT be retried)
+	ResStateHardFail
+)
+
+// Prometheus is the struct that contains information about the
+// prometheus instance. Run Init() on it.
+type Prometheus struct {
+	Listen string // the listen specification for the net/http server
+
+	checkApplyTotal        *prometheus.CounterVec // total of CheckApplies that have been triggered
+	pgraphStartTimeSeconds prometheus.Gauge       // process start time in seconds since unix epoch
+	managedResources       *prometheus.GaugeVec   // Resources we manage now
+	failedResourcesTotal   *prometheus.CounterVec // Total of failures since mgmt has started
+	failedResources        *prometheus.GaugeVec   // Number of current resources
+
+	resourcesState map[string]resStateWithKind // Maps the resources with their current kind/state
+	mutex          *sync.Mutex                 // Mutex used to update resourcesState
+}
+
+// resStateWithKind is used to count the failures by kind
+type resStateWithKind struct {
+	state ResState
+	kind  string
+}
+
+// Init some parameters - currently the Listen address.
+func (obj *Prometheus) Init() error {
+	if len(obj.Listen) == 0 {
+		obj.Listen = DefaultPrometheusListen
+	}
+
+	obj.mutex = &sync.Mutex{}
+	obj.resourcesState = make(map[string]resStateWithKind)
+
+	obj.checkApplyTotal = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "mgmt_checkapply_total",
+			Help: "Number of CheckApply that have run.",
+		},
+		// Labels for this metric.
+		// kind: resource type: Svc, File, ...
+		// apply: if the CheckApply happened in "apply" mode
+		// eventful: did the CheckApply generate an event
+		// errorful: did the CheckApply generate an error
+		[]string{"kind", "apply", "eventful", "errorful"},
+	)
+	prometheus.MustRegister(obj.checkApplyTotal)
+
+	obj.pgraphStartTimeSeconds = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Name: "mgmt_graph_start_time_seconds",
+			Help: "Start time of the current graph since unix epoch in seconds.",
+		},
+	)
+	prometheus.MustRegister(obj.pgraphStartTimeSeconds)
+
+	obj.managedResources = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "mgmt_resources",
+			Help: "Number of managed resources.",
+		},
+		// kind: resource type: Svc, File, ...
+		[]string{"kind"},
+	)
+	prometheus.MustRegister(obj.managedResources)
+
+	obj.failedResourcesTotal = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "mgmt_failures_total",
+			Help: "Total of failed resources.",
+		},
+		// kind: resource type: Svc, File, ...
+		// failure: soft or hard
+		[]string{"kind", "failure"},
+	)
+	prometheus.MustRegister(obj.failedResourcesTotal)
+
+	obj.failedResources = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "mgmt_failures",
+			Help: "Number of failing resources.",
+		},
+		// kind: resource type: Svc, File, ...
+		// failure: soft or hard
+		[]string{"kind", "failure"},
+	)
+	prometheus.MustRegister(obj.failedResources)
+
+	return nil
+}
+
+// Start runs a http server in a go routine, that responds to /metrics
+// as prometheus would expect.
+func (obj *Prometheus) Start() error {
+	http.Handle("/metrics", promhttp.Handler())
+	go http.ListenAndServe(obj.Listen, nil)
+	return nil
+}
+
+// Stop the http server.
+func (obj *Prometheus) Stop() error {
+	// TODO: There is no way in go < 1.8 to stop a http server.
+	// https://stackoverflow.com/questions/39320025/go-how-to-stop-http-listenandserve/41433555#41433555
+	return nil
+}
+
+// UpdateCheckApplyTotal refreshes the failing gauge by parsing the internal
+// state map.
+func (obj *Prometheus) UpdateCheckApplyTotal(kind string, apply, eventful, errorful bool) error {
+	if obj == nil {
+		return nil // happens when mgmt is launched without --prometheus
+	}
+	labels := prometheus.Labels{"kind": kind, "apply": strconv.FormatBool(apply), "eventful": strconv.FormatBool(eventful), "errorful": strconv.FormatBool(errorful)}
+	metric := obj.checkApplyTotal.With(labels)
+	metric.Inc()
+	return nil
+}
+
+// UpdatePgraphStartTime updates the mgmt_graph_start_time_seconds metric
+// to the current timestamp.
+func (obj *Prometheus) UpdatePgraphStartTime() error {
+	if obj == nil {
+		return nil // happens when mgmt is launched without --prometheus
+	}
+	obj.pgraphStartTimeSeconds.SetToCurrentTime()
+	return nil
+}
+
+// AddManagedResource increments the Managed Resource counter and updates the resource status.
+func (obj *Prometheus) AddManagedResource(resUUID string, rtype string) error {
+	if obj == nil {
+		return nil // happens when mgmt is launched without --prometheus
+	}
+	obj.managedResources.With(prometheus.Labels{"kind": rtype}).Inc()
+	if err := obj.UpdateState(resUUID, rtype, ResStateOK); err != nil {
+		return errwrap.Wrapf(err, "can't update the resource status in the map")
+	}
+	return nil
+}
+
+// RemoveManagedResource decrements the Managed Resource counter and updates the resource status.
+func (obj *Prometheus) RemoveManagedResource(resUUID string, rtype string) error {
+	if obj == nil {
+		return nil // happens when mgmt is launched without --prometheus
+	}
+	obj.managedResources.With(prometheus.Labels{"kind": rtype}).Dec()
+	if err := obj.deleteState(resUUID); err != nil {
+		return errwrap.Wrapf(err, "can't remove the resource status from the map")
+	}
+	return nil
+}
+
+// deleteState removes the resources for the state map and re-populates the failing gauge.
+func (obj *Prometheus) deleteState(resUUID string) error {
+	if obj == nil {
+		return nil // happens when mgmt is launched without --prometheus
+	}
+	obj.mutex.Lock()
+	delete(obj.resourcesState, resUUID)
+	obj.mutex.Unlock()
+	if err := obj.updateFailingGauge(); err != nil {
+		return errwrap.Wrapf(err, "can't update the failing gauge")
+	}
+	return nil
+}
+
+// UpdateState updates the state of the resources in our internal state map
+// then triggers a refresh of the failing gauge.
+func (obj *Prometheus) UpdateState(resUUID string, rtype string, newState ResState) error {
+	defer obj.updateFailingGauge()
+	if obj == nil {
+		return nil // happens when mgmt is launched without --prometheus
+	}
+	obj.mutex.Lock()
+	obj.resourcesState[resUUID] = resStateWithKind{state: newState, kind: rtype}
+	obj.mutex.Unlock()
+	if newState != ResStateOK {
+		var strState string
+		if newState == ResStateSoftFail {
+			strState = "soft"
+		} else if newState == ResStateHardFail {
+			strState = "hard"
+		} else {
+			return errors.New("state should be soft or hard failure")
+		}
+		obj.failedResourcesTotal.With(prometheus.Labels{"kind": rtype, "failure": strState}).Inc()
+	}
+	return nil
+}
+
+// updateFailingGauge refreshes the failing gauge by parsking the internal
+// state map.
+func (obj *Prometheus) updateFailingGauge() error {
+	if obj == nil {
+		return nil // happens when mgmt is launched without --prometheus
+	}
+	var softFails, hardFails map[string]float64
+	softFails = make(map[string]float64)
+	hardFails = make(map[string]float64)
+	for _, v := range obj.resourcesState {
+		if v.state == ResStateSoftFail {
+			softFails[v.kind]++
+		} else if v.state == ResStateHardFail {
+			hardFails[v.kind]++
+		}
+	}
+	// TODO: we might want to Zero the metrics we are not using
+	// because in prometheus design the metrics keep living for some time
+	// even after they are removed.
+	obj.failedResources.Reset()
+	for k, v := range softFails {
+		obj.failedResources.With(prometheus.Labels{"kind": k, "failure": "soft"}).Set(v)
+	}
+	for k, v := range hardFails {
+		obj.failedResources.With(prometheus.Labels{"kind": k, "failure": "hard"}).Set(v)
+	}
+	return nil
+}

puppet/gapi.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 package puppet
@@ -50,10 +50,10 @@ func NewGAPI(data gapi.Data, puppetParam *string, puppetConf string) (*GAPI, err
 // Init initializes the puppet GAPI struct.
 func (obj *GAPI) Init(data gapi.Data) error {
 	if obj.initialized {
-		return fmt.Errorf("Already initialized!")
+		return fmt.Errorf("already initialized")
 	}
 	if obj.PuppetParam == nil {
-		return fmt.Errorf("The PuppetParam param must be specified!")
+		return fmt.Errorf("the PuppetParam param must be specified")
 	}
 	obj.data = data // store for later
 	obj.closeChan = make(chan struct{})
@@ -64,43 +64,72 @@ func (obj *GAPI) Init(data gapi.Data) error {
 // Graph returns a current Graph.
 func (obj *GAPI) Graph() (*pgraph.Graph, error) {
 	if !obj.initialized {
-		return nil, fmt.Errorf("Puppet: GAPI is not initialized!")
+		return nil, fmt.Errorf("the puppet GAPI is not initialized")
 	}
 	config := ParseConfigFromPuppet(*obj.PuppetParam, obj.PuppetConf)
 	if config == nil {
-		return nil, fmt.Errorf("Puppet: ParseConfigFromPuppet returned nil!")
+		return nil, fmt.Errorf("function ParseConfigFromPuppet returned nil")
 	}
 	g, err := config.NewGraphFromConfig(obj.data.Hostname, obj.data.World, obj.data.Noop)
 	return g, err
 }
 
 // Next returns nil errors every time there could be a new graph.
-func (obj *GAPI) Next() chan error {
-	if obj.data.NoWatch {
-		return nil
-	}
+func (obj *GAPI) Next() chan gapi.Next {
 	puppetChan := func() <-chan time.Time { // helper function
-		return time.Tick(time.Duration(PuppetInterval(obj.PuppetConf)) * time.Second)
+		return time.Tick(time.Duration(RefreshInterval(obj.PuppetConf)) * time.Second)
 	}
-	ch := make(chan error)
+	ch := make(chan gapi.Next)
 	obj.wg.Add(1)
 	go func() {
 		defer obj.wg.Done()
 		defer close(ch) // this will run before the obj.wg.Done()
 		if !obj.initialized {
-			ch <- fmt.Errorf("Puppet: GAPI is not initialized!")
+			next := gapi.Next{
+				Err:  fmt.Errorf("the puppet GAPI is not initialized"),
+				Exit: true, // exit, b/c programming error?
+			}
+			ch <- next
 			return
 		}
-		pChan := puppetChan()
+		startChan := make(chan struct{}) // start signal
+		close(startChan)                 // kick it off!
+
+		pChan := make(<-chan time.Time)
+		// NOTE: we don't look at obj.data.NoConfigWatch since emulating
+		// puppet means we do not switch graphs on code changes anyways.
+		if obj.data.NoStreamWatch {
+			pChan = nil
+		} else {
+			pChan = puppetChan()
+		}
+
 		for {
 			select {
+			case <-startChan: // kick the loop once at start
+				startChan = nil // disable
+				// pass
 			case _, ok := <-pChan:
 				if !ok { // the channel closed!
 					return
 				}
-				log.Printf("Puppet: Generating new graph...")
+			case <-obj.closeChan:
+				return
+			}
+
+			log.Printf("Puppet: Generating new graph...")
+			if obj.data.NoStreamWatch {
+				pChan = nil
+			} else {
 				pChan = puppetChan() // TODO: okay to update interval in case it changed?
-				ch <- nil            // trigger a run
+			}
+			next := gapi.Next{
+				//Exit: true, // TODO: for permanent shutdown!
+				Err: nil,
+			}
+			select {
+			case ch <- next: // trigger a run (send a msg)
+			// unblock if we exit while waiting to send!
 			case <-obj.closeChan:
 				return
 			}
@@ -112,7 +141,7 @@ func (obj *GAPI) Next() chan error {
 // Close shuts down the Puppet GAPI.
 func (obj *GAPI) Close() error {
 	if !obj.initialized {
-		return fmt.Errorf("Puppet: GAPI is not initialized!")
+		return fmt.Errorf("the puppet GAPI is not initialized")
 	}
 	close(obj.closeChan)
 	obj.wg.Wait()

puppet/puppet.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 // Package puppet provides the integration entrypoint for the puppet language.
@@ -116,8 +116,8 @@ func ParseConfigFromPuppet(puppetParam, puppetConf string) *yamlgraph.GraphConfi
 	return &config
 }
 
-// PuppetInterval returns the graph refresh interval from the puppet configuration.
-func PuppetInterval(puppetConf string) int {
+// RefreshInterval returns the graph refresh interval from the puppet configuration.
+func RefreshInterval(puppetConf string) int {
 	if Debug {
 		log.Printf("Puppet: determining graph refresh interval")
 	}

recwatch/configwatch.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 package recwatch
@@ -59,15 +59,23 @@ func (obj *ConfigWatcher) Add(file ...string) {
 		ch := obj.ConfigWatch(file[0])
 		for {
 			select {
-			case e := <-ch:
+			case e, ok := <-ch:
+				if !ok { // channel closed
+					return
+				}
 				if e != nil {
 					obj.errorchan <- e
 					return
 				}
-				obj.ch <- file[0]
+				select {
+				case obj.ch <- file[0]: // send on channel
+				case <-obj.closechan:
+					return // never mind, close early!
+				}
 				continue
-			case <-obj.closechan:
-				return
+				// not needed, closes via ConfigWatch() chan close
+				//case <-obj.closechan:
+				//	return
 			}
 		}
 	}()
@@ -126,7 +134,12 @@ func (obj *ConfigWatcher) ConfigWatch(file string) chan error {
 					close(ch)
 					return
 				}
-				ch <- nil // send event!
+				select {
+				case ch <- nil: // send event!
+				case <-obj.closechan:
+					close(ch)
+					return
+				}
 			}
 		}
 		//close(ch)

recwatch/flags.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 package recwatch

recwatch/recwatch.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 // Package recwatch provides recursive file watching events via fsnotify.
@@ -51,10 +51,10 @@ type RecWatcher struct {
 	watcher  *fsnotify.Watcher
 	watches  map[string]struct{}
 	events   chan Event // one channel for events and err...
-	once     sync.Once
+	closed   bool       // is the events channel closed?
+	mutex    sync.Mutex // lock guarding the channel closing
 	wg       sync.WaitGroup
 	exit     chan struct{}
-	closeErr error
 }
 
 // NewRecWatcher creates an initializes a new recursive watcher.
@@ -87,11 +87,22 @@ func (obj *RecWatcher) Init() error {
 		}
 	}
 
+	obj.wg.Add(1)
 	go func() {
+		defer obj.wg.Done()
 		if err := obj.Watch(); err != nil {
-			obj.events <- Event{Error: err}
+			// we need this mutex, because if we Init and then Close
+			// immediately, this can send after closed which panics!
+			obj.mutex.Lock()
+			if !obj.closed {
+				select {
+				case obj.events <- Event{Error: err}:
+				case <-obj.exit:
+					// pass
+				}
+			}
+			obj.mutex.Unlock()
 		}
-		obj.Close()
 	}()
 	return nil
 }
@@ -106,26 +117,18 @@ func (obj *RecWatcher) Init() error {
 
 // Close shuts down the watcher.
 func (obj *RecWatcher) Close() error {
-	obj.once.Do(obj.close) // don't cause the channel to close twice
-	return obj.closeErr
-}
-
-// This close function is the function that actually does the close work. Don't
-// call it more than once!
-func (obj *RecWatcher) close() {
 	var err error
 	close(obj.exit) // send exit signal
 	obj.wg.Wait()
 	if obj.watcher != nil {
 		err = obj.watcher.Close()
 		obj.watcher = nil
-		// TODO: should we send the close error?
-		//if err != nil {
-		//	obj.events <- Event{Error: err}
-		//}
 	}
+	obj.mutex.Lock() // FIXME: I don't think this mutex is needed anymore...
+	obj.closed = true
 	close(obj.events)
-	obj.closeErr = err // set the error
+	obj.mutex.Unlock()
+	return err
 }
 
 // Events returns a channel of events. These include events for errors.
@@ -134,10 +137,8 @@ func (obj *RecWatcher) Events() chan Event { return obj.events }
 // Watch is the primary listener for this resource and it outputs events.
 func (obj *RecWatcher) Watch() error {
 	if obj.watcher == nil {
-		return fmt.Errorf("Watcher is not initialized!")
+		return fmt.Errorf("the watcher is not initialized")
 	}
-	obj.wg.Add(1)
-	defer obj.wg.Done()
 
 	patharray := util.PathSplit(obj.safename) // tokenize the path
 	var index = len(patharray)                // starting index
@@ -169,11 +170,11 @@ func (obj *RecWatcher) Watch() error {
 				// no space left on device, out of inotify watches
 				// TODO: consider letting the user fall back to
 				// polling if they hit this error very often...
-				return fmt.Errorf("Out of inotify watches: %v", err)
+				return fmt.Errorf("out of inotify watches: %v", err)
 			} else if os.IsPermission(err) {
-				return fmt.Errorf("Permission denied adding a watch: %v", err)
+				return fmt.Errorf("permission denied adding a watch: %v", err)
 			}
-			return fmt.Errorf("Unknown error: %v", err)
+			return fmt.Errorf("unknown error: %v", err)
 		}
 
 		select {
@@ -236,6 +237,13 @@ func (obj *RecWatcher) Watch() error {
 					index--
 				}
 
+				// when the file is moved, remove the watcher and add a new one,
+				// so we stop tracking the old inode.
+				if deltaDepth >= 0 && (event.Op&fsnotify.Rename == fsnotify.Rename) {
+					obj.watcher.Remove(current)
+					obj.watcher.Add(current)
+				}
+
 				// we must be a parent watcher, so descend in
 				if deltaDepth < 0 {
 					// XXX: we can block here due to: https://github.com/fsnotify/fsnotify/issues/123
@@ -272,11 +280,16 @@ func (obj *RecWatcher) Watch() error {
 			if send {
 				send = false
 				// only invalid state on certain types of events
-				obj.events <- Event{Error: nil, Body: &event}
+				select {
+				// exit even when we're blocked on event sending
+				case obj.events <- Event{Error: nil, Body: &event}:
+				case <-obj.exit:
+					return fmt.Errorf("pending event not sent")
+				}
 			}
 
 		case err := <-obj.watcher.Errors:
-			return fmt.Errorf("Unknown watcher error: %v", err)
+			return fmt.Errorf("unknown watcher error: %v", err)
 
 		case <-obj.exit:
 			return nil

remote/remote.go

@@ -1,18 +1,18 @@
 // Mgmt
-// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
 // Written by James Shubin <james@shubin.ca> and the project contributors
 //
 // This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
+// it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
 //
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
+// GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Affero General Public License
+// You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 // Package remote provides the remoting facilities for agentless execution.
@@ -63,6 +63,7 @@ import (
 
 	cv "github.com/purpleidea/mgmt/converger"
 	"github.com/purpleidea/mgmt/util"
+	"github.com/purpleidea/mgmt/util/semaphore"
 	"github.com/purpleidea/mgmt/yamlgraph"
 
 	multierr "github.com/hashicorp/go-multierror"
@@ -691,29 +692,30 @@ type Remotes struct {
 	fileWatch    chan string
 	cConns       uint16 // number of concurrent ssh connections, zero means unlimited
 	interactive  bool   // allow interactive prompting
-	sshPrivIdRsa string // path to ~/.ssh/id_rsa
+	sshPrivIDRsa string // path to ~/.ssh/id_rsa
 	caching      bool   // whether to try and cache the copy of the binary
 	depth        uint16 // depth of this node in the remote execution hierarchy
 	prefix       string // folder prefix to use for misc storage
 	converger    cv.Converger
 	convergerCb  func(func(map[string]bool) error) (func(), error)
 
-	wg                 sync.WaitGroup             // keep track of each running SSH connection
-	lock               sync.Mutex                 // mutex for access to sshmap
-	sshmap             map[string]*SSH            // map to each SSH struct with the remote as the key
-	exiting            bool                       // flag to let us know if we're exiting
-	exitChan           chan struct{}              // closes when we should exit
-	semaphore          Semaphore                  // counting semaphore to limit concurrent connections
-	hostnames          []string                   // list of hostnames we've seen so far
-	cuid               cv.ConvergerUID            // convergerUID for the remote itself
-	cuids              map[string]cv.ConvergerUID // map to each SSH struct with the remote as the key
-	callbackCancelFunc func()                     // stored callback function cancel function
+	wg                 sync.WaitGroup       // keep track of each running SSH connection
+	lock               sync.Mutex           // mutex for access to sshmap
+	sshmap             map[string]*SSH      // map to each SSH struct with the remote as the key
+	running            chan struct{}        // closes when main loop is running
+	exiting            bool                 // flag to let us know if we're exiting
+	exitChan           chan struct{}        // closes when we should exit
+	semaphore          *semaphore.Semaphore // counting semaphore to limit concurrent connections
+	hostnames          []string             // list of hostnames we've seen so far
+	cuid               cv.UID               // convergerUID for the remote itself
+	cuids              map[string]cv.UID    // map to each SSH struct with the remote as the key
+	callbackCancelFunc func()               // stored callback function cancel function
 
 	flags Flags // constant runtime values
 }
 
 // NewRemotes builds a Remotes struct.
-func NewRemotes(clientURLs, remoteURLs []string, noop bool, remotes []string, fileWatch chan string, cConns uint16, interactive bool, sshPrivIdRsa string, caching bool, depth uint16, prefix string, converger cv.Converger, convergerCb func(func(map[string]bool) error) (func(), error), flags Flags) *Remotes {
+func NewRemotes(clientURLs, remoteURLs []string, noop bool, remotes []string, fileWatch chan string, cConns uint16, interactive bool, sshPrivIDRsa string, caching bool, depth uint16, prefix string, converger cv.Converger, convergerCb func(func(map[string]bool) error) (func(), error), flags Flags) *Remotes {
 	return &Remotes{
 		clientURLs:   clientURLs,
 		remoteURLs:   remoteURLs,
@@ -722,17 +724,18 @@ func NewRemotes(clientURLs, remoteURLs []string, noop bool, remotes []string, fi
 		fileWatch:    fileWatch,
 		cConns:       cConns,
 		interactive:  interactive,
-		sshPrivIdRsa: sshPrivIdRsa,
+		sshPrivIDRsa: sshPrivIDRsa,
 		caching:      caching,
 		depth:        depth,
 		prefix:       prefix,
 		converger:    converger,
 		convergerCb:  convergerCb,
 		sshmap:       make(map[string]*SSH),
+		running:      make(chan struct{}),
 		exitChan:     make(chan struct{}),
-		semaphore:    NewSemaphore(int(cConns)),
+		semaphore:    semaphore.NewSemaphore(int(cConns)),
 		hostnames:    make([]string, len(remotes)),
-		cuids:        make(map[string]cv.ConvergerUID),
+		cuids:        make(map[string]cv.UID),
 		flags:        flags,
 	}
 }
@@ -829,18 +832,18 @@ func (obj *Remotes) NewSSH(file string) (*SSH, error) {
 
 // sshKeyAuth is a helper function to get the ssh key auth struct needed
 func (obj *Remotes) sshKeyAuth() (ssh.AuthMethod, error) {
-	if obj.sshPrivIdRsa == "" {
+	if obj.sshPrivIDRsa == "" {
 		return nil, fmt.Errorf("empty path specified")
 	}
 	p := ""
 	// TODO: this doesn't match strings of the form: ~james/.ssh/id_rsa
-	if strings.HasPrefix(obj.sshPrivIdRsa, "~/") {
+	if strings.HasPrefix(obj.sshPrivIDRsa, "~/") {
 		usr, err := user.Current()
 		if err != nil {
 			log.Printf("Remote: Can't find home directory automatically.")
 			return nil, err
 		}
-		p = path.Join(usr.HomeDir, obj.sshPrivIdRsa[len("~/"):])
+		p = path.Join(usr.HomeDir, obj.sshPrivIDRsa[len("~/"):])
 	}
 	if p == "" {
 		return nil, fmt.Errorf("empty path specified")
@@ -1021,11 +1024,17 @@ func (obj *Remotes) Run() {
 		}(sshobj, f)
 		obj.lock.Unlock()
 	}
+	close(obj.running) // notify
 }
 
+// Ready closes its returned channel when the Run method is up and ready. It is
+// useful to know when ready, since we often execute Run in a go routine.
+func (obj *Remotes) Ready() <-chan struct{} { return obj.running }
+
 // Exit causes as much of the Remotes struct to shutdown as quickly and as
 // cleanly as possible. It only returns once everything is shutdown.
 func (obj *Remotes) Exit() error {
+	<-obj.running // wait for Run to be finished before we exit!
 	obj.lock.Lock()
 	obj.exiting = true // don't spawn new ones once this flag is set!
 	obj.lock.Unlock()
@@ -1078,29 +1087,6 @@ func cleanURL(s string) string {
 	return u.Host
 }
 
-// Semaphore is a counting semaphore.
-type Semaphore chan struct{}
-
-// NewSemaphore creates a new semaphore.
-func NewSemaphore(size int) Semaphore {
-	return make(Semaphore, size)
-}
-
-// P acquires n resources.
-func (s Semaphore) P(n int) {
-	e := struct{}{}
-	for i := 0; i < n; i++ {
-		s <- e // acquire one
-	}
-}
-
-// V releases n resources.
-func (s Semaphore) V(n int) {
-	for i := 0; i < n; i++ {
-		<-s // release one
-	}
-}
-
 // combinedWriter mimics what the ssh.CombinedOutput command does.
 type combinedWriter struct {
 	b  bytes.Buffer

resources/actions.go

@@ -0,0 +1,649 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package resources
+
+import (
+	"fmt"
+	"log"
+	"math"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/purpleidea/mgmt/event"
+	"github.com/purpleidea/mgmt/pgraph"
+	"github.com/purpleidea/mgmt/prometheus"
+	"github.com/purpleidea/mgmt/util"
+
+	multierr "github.com/hashicorp/go-multierror"
+	errwrap "github.com/pkg/errors"
+	"golang.org/x/time/rate"
+)
+
+// SentinelErr is a sentinal as an error type that wraps an arbitrary error.
+type SentinelErr struct {
+	err error
+}
+
+// Error is the required method to fulfill the error type.
+func (obj *SentinelErr) Error() string {
+	return obj.err.Error()
+}
+
+// OKTimestamp returns true if this element can run right now?
+func (obj *BaseRes) OKTimestamp() bool {
+	// these are all the vertices pointing TO v, eg: ??? -> v
+	for _, n := range obj.Graph.IncomingGraphVertices(obj.Vertex) {
+		// if the vertex has a greater timestamp than any pre-req (n)
+		// then we can't run right now...
+		// if they're equal (eg: on init of 0) then we also can't run
+		// b/c we should let our pre-req's go first...
+		x, y := obj.Timestamp(), VtoR(n).Timestamp()
+		if b, ok := obj.Graph.Value("debug"); ok && util.Bool(b) {
+			log.Printf("%s: OKTimestamp: (%v) >= %s(%v): !%v", obj, x, n, y, x >= y)
+		}
+		if x >= y {
+			return false
+		}
+	}
+	return true
+}
+
+// Poke tells nodes after me in the dependency graph that they need to refresh.
+func (obj *BaseRes) Poke() error {
+	// if we're pausing (or exiting) then we should suspend poke's so that
+	// the graph doesn't go on running forever until it's completely done!
+	// this is an optional feature which we can do by default on user exit
+	if obj.Graph.FastPause {
+		return nil // TODO: should this be an error instead?
+	}
+
+	var wg sync.WaitGroup
+	// these are all the vertices pointing AWAY FROM v, eg: v -> ???
+	for _, n := range obj.Graph.OutgoingGraphVertices(obj.Vertex) {
+		// we can skip this poke if resource hasn't done work yet... it
+		// needs to be poked if already running, or not running though!
+		// TODO: does this need an || activity flag?
+		if VtoR(n).GetState() != ResStateProcess {
+			if b, ok := obj.Graph.Value("debug"); ok && util.Bool(b) {
+				log.Printf("%s: Poke: %s", obj, n)
+			}
+			wg.Add(1)
+			go func(nn pgraph.Vertex) error {
+				defer wg.Done()
+				//edge := obj.Graph.adjacency[v][nn] // lookup
+				//notify := edge.Notify && edge.Refresh()
+				return VtoR(nn).SendEvent(event.EventPoke, nil)
+			}(n)
+
+		} else {
+			if b, ok := obj.Graph.Value("debug"); ok && util.Bool(b) {
+				log.Printf("%s: Poke: %s: Skipped!", obj, n)
+			}
+		}
+	}
+	// TODO: do something with return values?
+	wg.Wait() // wait for all the pokes to complete
+	return nil
+}
+
+// BackPoke pokes the pre-requisites that are stale and need to run before I can run.
+func (obj *BaseRes) BackPoke() {
+	var wg sync.WaitGroup
+	// these are all the vertices pointing TO v, eg: ??? -> v
+	for _, n := range obj.Graph.IncomingGraphVertices(obj.Vertex) {
+		x, y, s := obj.Timestamp(), VtoR(n).Timestamp(), VtoR(n).GetState()
+		// If the parent timestamp needs poking AND it's not running
+		// Process, then poke it. If the parent is in ResStateProcess it
+		// means that an event is pending, so we'll be expecting a poke
+		// back soon, so we can safely discard the extra parent poke...
+		// TODO: implement a stateLT (less than) to tell if something
+		// happens earlier in the state cycle and that doesn't wrap nil
+		if x >= y && (s != ResStateProcess && s != ResStateCheckApply) {
+			if b, ok := obj.Graph.Value("debug"); ok && util.Bool(b) {
+				log.Printf("%s: BackPoke: %s", obj, n)
+			}
+			wg.Add(1)
+			go func(nn pgraph.Vertex) error {
+				defer wg.Done()
+				return VtoR(nn).SendEvent(event.EventBackPoke, nil)
+			}(n)
+
+		} else {
+			if b, ok := obj.Graph.Value("debug"); ok && util.Bool(b) {
+				log.Printf("%s: BackPoke: %s: Skipped!", obj, n)
+			}
+		}
+	}
+	// TODO: do something with return values?
+	wg.Wait() // wait for all the pokes to complete
+}
+
+// RefreshPending determines if any previous nodes have a refresh pending here.
+// If this is true, it means I am expected to apply a refresh when I next run.
+func (obj *BaseRes) RefreshPending() bool {
+	var refresh bool
+	for _, edge := range obj.Graph.IncomingGraphEdges(obj.Vertex) {
+		// if we asked for a notify *and* if one is pending!
+		edge := edge.(*Edge) // panic if wrong
+		if edge.Notify && edge.Refresh() {
+			refresh = true
+			break
+		}
+	}
+	return refresh
+}
+
+// SetUpstreamRefresh sets the refresh value to any upstream vertices.
+func (obj *BaseRes) SetUpstreamRefresh(b bool) {
+	for _, edge := range obj.Graph.IncomingGraphEdges(obj.Vertex) {
+		edge := edge.(*Edge) // panic if wrong
+		if edge.Notify {
+			edge.SetRefresh(b)
+		}
+	}
+}
+
+// SetDownstreamRefresh sets the refresh value to any downstream vertices.
+func (obj *BaseRes) SetDownstreamRefresh(b bool) {
+	for _, edge := range obj.Graph.OutgoingGraphEdges(obj.Vertex) {
+		edge := edge.(*Edge) // panic if wrong
+		// if we asked for a notify *and* if one is pending!
+		if edge.Notify {
+			edge.SetRefresh(b)
+		}
+	}
+}
+
+// Process is the primary function to execute for a particular vertex in the graph.
+func (obj *BaseRes) Process() error {
+	if obj.debug {
+		log.Printf("%s: Process()", obj)
+	}
+	// FIXME: should these SetState methods be here or after the sema code?
+	defer obj.SetState(ResStateNil) // reset state when finished
+	obj.SetState(ResStateProcess)
+
+	// is it okay to run dependency wise right now?
+	// if not, that's okay because when the dependency runs, it will poke
+	// us back and we will run if needed then!
+	if !obj.OKTimestamp() {
+		go obj.BackPoke()
+		return nil
+	}
+	// timestamp must be okay...
+	if b, ok := obj.Graph.Value("debug"); ok && util.Bool(b) {
+		log.Printf("%s: OKTimestamp(%v)", obj, obj.Timestamp())
+	}
+
+	// semaphores!
+	// These shouldn't ever block an exit, since the graph should eventually
+	// converge causing their them to unlock. More interestingly, since they
+	// run in a DAG alphabetically, there is no way to permanently deadlock,
+	// assuming that resources individually don't ever block from finishing!
+	// The exception is that semaphores with a zero count will always block!
+	// TODO: Add a close mechanism to close/unblock zero count semaphores...
+	semas := obj.Meta().Sema
+	if obj.debug && len(semas) > 0 {
+		log.Printf("%s: Sema: P(%s)", obj, strings.Join(semas, ", "))
+	}
+	if err := obj.Graph.SemaLock(semas); err != nil { // lock
+		// NOTE: in practice, this might not ever be truly necessary...
+		return fmt.Errorf("shutdown of semaphores")
+	}
+	defer obj.Graph.SemaUnlock(semas) // unlock
+	if obj.debug && len(semas) > 0 {
+		defer log.Printf("%s: Sema: V(%s)", obj, strings.Join(semas, ", "))
+	}
+
+	var ok = true
+	var applied = false // did we run an apply?
+
+	// connect any senders to receivers and detect if values changed
+	if updated, err := obj.SendRecv(obj.Res); err != nil {
+		return errwrap.Wrapf(err, "could not SendRecv in Process")
+	} else if len(updated) > 0 {
+		for _, changed := range updated {
+			if changed { // at least one was updated
+				obj.StateOK(false) // invalidate cache, mark as dirty
+				break
+			}
+		}
+	}
+
+	var noop = obj.Meta().Noop // lookup the noop value
+	var refresh bool
+	var checkOK bool
+	var err error
+
+	if b, ok := obj.Graph.Value("debug"); ok && util.Bool(b) {
+		log.Printf("%s: CheckApply(%t)", obj, !noop)
+	}
+
+	// lookup the refresh (notification) variable
+	refresh = obj.RefreshPending() // do i need to perform a refresh?
+	obj.SetRefresh(refresh)        // tell the resource
+
+	// changes can occur after this...
+	obj.SetState(ResStateCheckApply)
+
+	// check cached state, to skip CheckApply; can't skip if refreshing
+	if !refresh && obj.IsStateOK() {
+		checkOK, err = true, nil
+
+		// NOTE: technically this block is wrong because we don't know
+		// if the resource implements refresh! If it doesn't, we could
+		// skip this, but it doesn't make a big difference under noop!
+	} else if noop && refresh { // had a refresh to do w/ noop!
+		checkOK, err = false, nil // therefore the state is wrong
+
+		// run the CheckApply!
+	} else {
+		// if this fails, don't UpdateTimestamp()
+		checkOK, err = obj.Res.CheckApply(!noop)
+
+		if promErr := obj.Data().Prometheus.UpdateCheckApplyTotal(obj.GetKind(), !noop, !checkOK, err != nil); promErr != nil {
+			// TODO: how to error correctly
+			log.Printf("%s: Prometheus.UpdateCheckApplyTotal() errored: %v", obj, err)
+		}
+		// TODO: Can the `Poll` converged timeout tracking be a
+		// more general method for all converged timeouts? this
+		// would simplify the resources by removing boilerplate
+		if obj.Meta().Poll > 0 {
+			if !checkOK { // something changed, restart timer
+				obj.cuid.ResetTimer() // activity!
+				if b, ok := obj.Graph.Value("debug"); ok && util.Bool(b) {
+					log.Printf("%s: Converger: ResetTimer", obj)
+				}
+			}
+		}
+	}
+
+	if checkOK && err != nil { // should never return this way
+		log.Fatalf("%s: CheckApply(): %t, %+v", obj, checkOK, err)
+	}
+	if b, ok := obj.Graph.Value("debug"); ok && util.Bool(b) {
+		log.Printf("%s: CheckApply(): %t, %v", obj, checkOK, err)
+	}
+
+	// if CheckApply ran without noop and without error, state should be good
+	if !noop && err == nil { // aka !noop || checkOK
+		obj.StateOK(true) // reset
+		if refresh {
+			obj.SetUpstreamRefresh(false) // refresh happened, clear the request
+			obj.SetRefresh(false)
+		}
+	}
+
+	if !checkOK { // if state *was* not ok, we had to have apply'ed
+		if err != nil { // error during check or apply
+			ok = false
+		} else {
+			applied = true
+		}
+	}
+
+	// when noop is true we always want to update timestamp
+	if noop && err == nil {
+		ok = true
+	}
+
+	if ok {
+		// did we actually do work?
+		activity := applied
+		if noop {
+			activity = false // no we didn't do work...
+		}
+
+		if activity { // add refresh flag to downstream edges...
+			obj.SetDownstreamRefresh(true)
+		}
+
+		// update this timestamp *before* we poke or the poked
+		// nodes might fail due to having a too old timestamp!
+		obj.UpdateTimestamp()        // this was touched...
+		obj.SetState(ResStatePoking) // can't cancel parent poke
+		if err := obj.Poke(); err != nil {
+			return errwrap.Wrapf(err, "the Poke() failed")
+		}
+	}
+	// poke at our pre-req's instead since they need to refresh/run...
+	return errwrap.Wrapf(err, "could not Process() successfully")
+}
+
+// innerWorker is the CheckApply runner that reads from processChan.
+func (obj *BaseRes) innerWorker() {
+	running := false
+	done := make(chan struct{})
+	playback := false // do we need to run another one?
+
+	waiting := false
+	var timer = time.NewTimer(time.Duration(math.MaxInt64)) // longest duration
+	if !timer.Stop() {
+		<-timer.C // unnecessary, shouldn't happen
+	}
+
+	var delay = time.Duration(obj.Meta().Delay) * time.Millisecond
+	var retry = obj.Meta().Retry // number of tries left, -1 for infinite
+	var limiter = rate.NewLimiter(obj.Meta().Limit, obj.Meta().Burst)
+	limited := false
+
+	wg := &sync.WaitGroup{} // wait for Process routine to exit
+
+Loop:
+	for {
+		select {
+		case ev, ok := <-obj.processChan: // must use like this
+			if !ok { // processChan closed, let's exit
+				break Loop // no event, so no ack!
+			}
+			if obj.Meta().Poll == 0 { // skip for polling
+				obj.wcuid.SetConverged(false)
+			}
+
+			// if process started, but no action yet, skip!
+			if obj.GetState() == ResStateProcess {
+				if b, ok := obj.Graph.Value("debug"); ok && util.Bool(b) {
+					log.Printf("%s: Skipped event!", obj)
+				}
+				ev.ACK() // ready for next message
+				obj.quiesceGroup.Done()
+				continue
+			}
+
+			// if running, we skip running a new execution!
+			// if waiting, we skip running a new execution!
+			if running || waiting {
+				if b, ok := obj.Graph.Value("debug"); ok && util.Bool(b) {
+					log.Printf("%s: Playback added!", obj)
+				}
+				playback = true
+				ev.ACK() // ready for next message
+				obj.quiesceGroup.Done()
+				continue
+			}
+
+			// catch invalid rates
+			if obj.Meta().Burst == 0 && !(obj.Meta().Limit == rate.Inf) { // blocked
+				e := fmt.Errorf("%s: Permanently limited (rate != Inf, burst: 0)", obj)
+				ev.ACK() // ready for next message
+				obj.quiesceGroup.Done()
+				obj.SendEvent(event.EventExit, &SentinelErr{e})
+				continue
+			}
+
+			// rate limit
+			// FIXME: consider skipping rate limit check if
+			// the event is a poke instead of a watch event
+			if !limited && !(obj.Meta().Limit == rate.Inf) { // skip over the playback event...
+				now := time.Now()
+				r := limiter.ReserveN(now, 1) // one event
+				// r.OK() seems to always be true here!
+				d := r.DelayFrom(now)
+				if d > 0 { // delay
+					limited = true
+					playback = true
+					log.Printf("%s: Limited (rate: %v/sec, burst: %d, next: %v)", obj, obj.Meta().Limit, obj.Meta().Burst, d)
+					// start the timer...
+					timer.Reset(d)
+					waiting = true // waiting for retry timer
+					ev.ACK()
+					obj.quiesceGroup.Done()
+					continue
+				} // otherwise, we run directly!
+			}
+			limited = false // let one through
+
+			wg.Add(1)
+			running = true
+			go func(ev *event.Event) {
+				obj.pcuid.SetConverged(false) // "block" Process
+				defer wg.Done()
+				if e := obj.Process(); e != nil {
+					playback = true
+					log.Printf("%s: CheckApply errored: %v", obj, e)
+					if retry == 0 {
+						if err := obj.Data().Prometheus.UpdateState(obj.String(), obj.GetKind(), prometheus.ResStateHardFail); err != nil {
+							// TODO: how to error this?
+							log.Printf("%s: Prometheus.UpdateState() errored: %v", obj, err)
+						}
+
+						// wrap the error in the sentinel
+						obj.quiesceGroup.Done() // before the Wait that happens in SendEvent!
+						obj.SendEvent(event.EventExit, &SentinelErr{e})
+						return
+					}
+					if retry > 0 { // don't decrement the -1
+						retry--
+					}
+					if err := obj.Data().Prometheus.UpdateState(obj.String(), obj.GetKind(), prometheus.ResStateSoftFail); err != nil {
+						// TODO: how to error this?
+						log.Printf("%s: Prometheus.UpdateState() errored: %v", obj, err)
+					}
+					log.Printf("%s: CheckApply: Retrying after %.4f seconds (%d left)", obj, delay.Seconds(), retry)
+					// start the timer...
+					timer.Reset(delay)
+					waiting = true // waiting for retry timer
+					// don't obj.quiesceGroup.Done() b/c
+					// the timer is running and it can exit!
+					return
+				}
+				retry = obj.Meta().Retry // reset on success
+				close(done)              // trigger
+			}(ev)
+			ev.ACK() // sync (now mostly useless)
+
+		case <-timer.C:
+			if obj.Meta().Poll == 0 { // skip for polling
+				obj.wcuid.SetConverged(false)
+			}
+			waiting = false
+			if !timer.Stop() {
+				//<-timer.C // blocks, docs are wrong!
+			}
+			log.Printf("%s: CheckApply delay expired!", obj)
+			close(done)
+
+		// a CheckApply run (with possibly retry pause) finished
+		case <-done:
+			if obj.Meta().Poll == 0 { // skip for polling
+				obj.wcuid.SetConverged(false)
+			}
+			if b, ok := obj.Graph.Value("debug"); ok && util.Bool(b) {
+				log.Printf("%s: CheckApply finished!", obj)
+			}
+			done = make(chan struct{}) // reset
+			// re-send this event, to trigger a CheckApply()
+			if playback {
+				// this lock avoids us sending to
+				// channel after we've closed it!
+				// TODO: can this experience indefinite postponement ?
+				// see: https://github.com/golang/go/issues/11506
+				// pause or exit is in process if not quiescing!
+				if !obj.quiescing {
+					playback = false
+					obj.quiesceGroup.Add(1) // lock around it, b/c still running...
+					go func() {
+						obj.Event() // replay a new event
+						obj.quiesceGroup.Done()
+					}()
+				}
+			}
+			running = false
+			obj.pcuid.SetConverged(true) // "unblock" Process
+			obj.quiesceGroup.Done()
+
+		case <-obj.wcuid.ConvergedTimer():
+			obj.wcuid.SetConverged(true) // converged!
+			continue
+		}
+	}
+	wg.Wait()
+	return
+}
+
+// Worker is the common run frontend of the vertex. It handles all of the retry
+// and retry delay common code, and ultimately returns the final status of this
+// vertex execution.
+func (obj *BaseRes) Worker() error {
+	// listen for chan events from Watch() and run
+	// the Process() function when they're received
+	// this avoids us having to pass the data into
+	// the Watch() function about which graph it is
+	// running on, which isolates things nicely...
+	if obj.debug {
+		log.Printf("%s: Worker: Running", obj)
+		defer log.Printf("%s: Worker: Stopped", obj)
+	}
+	// run the init (should match 1-1 with Close function)
+	if err := obj.Res.Init(); err != nil {
+		obj.ProcessExit()
+		// always exit the worker function by finishing with Close()
+		if e := obj.Res.Close(); e != nil {
+			err = multierr.Append(err, e) // list of errors
+		}
+		return errwrap.Wrapf(err, "could not Init() resource")
+	}
+
+	// if the CheckApply run takes longer than the converged
+	// timeout, we could inappropriately converge mid-apply!
+	// avoid this by blocking convergence with a fake report
+	// we also add a similar blocker around the worker loop!
+	// XXX: put these in Init() ?
+	// get extra cuids (worker, process)
+	obj.wcuid.SetConverged(true) // starts off false, and waits for loop timeout
+	obj.pcuid.SetConverged(true) // starts off true, because it's not running...
+
+	obj.processSync.Add(1)
+	go func() {
+		defer obj.processSync.Done()
+		obj.innerWorker()
+	}()
+
+	var err error // propagate the error up (this is a permanent BAD error!)
+	// the watch delay runs inside of the Watch resource loop, so that it
+	// can still process signals and exit if needed. It shouldn't run any
+	// resource specific code since this is supposed to be a retry delay.
+	// NOTE: we're using the same retry and delay metaparams that CheckApply
+	// uses. This is for practicality. We can separate them later if needed!
+	var watchDelay time.Duration
+	var watchRetry = obj.Meta().Retry // number of tries left, -1 for infinite
+	// watch blocks until it ends, & errors to retry
+	for {
+		// TODO: do we have to stop the converged-timeout when in this block (perhaps we're in the delay block!)
+		// TODO: should we setup/manage some of the converged timeout stuff in here anyways?
+
+		// if a retry-delay was requested, wait, but don't block our events!
+		if watchDelay > 0 {
+			//var pendingSendEvent bool
+			timer := time.NewTimer(watchDelay)
+		Loop:
+			for {
+				select {
+				case <-timer.C: // the wait is over
+					break Loop // critical
+
+				// TODO: resources could have a separate exit channel to avoid this complexity!?
+				case event := <-obj.Events():
+					// NOTE: this code should match the similar Res code!
+					//cuid.SetConverged(false) // TODO: ?
+					if exit, send := obj.ReadEvent(event); exit != nil {
+						obj.ProcessExit()
+						err := *exit // exit err
+						if e := obj.Res.Close(); err == nil {
+							err = e
+						} else if e != nil {
+							err = multierr.Append(err, e) // list of errors
+						}
+						return err // exit
+					} else if send {
+						// if we dive down this rabbit hole, our
+						// timer.C won't get seen until we get out!
+						// in this situation, the Watch() is blocked
+						// from performing until CheckApply returns
+						// successfully, or errors out. This isn't
+						// so bad, but we should document it. Is it
+						// possible that some resource *needs* Watch
+						// to run to be able to execute a CheckApply?
+						// That situation shouldn't be common, and
+						// should probably not be allowed. Can we
+						// avoid it though?
+						//if exit, err := doSend(); exit || err != nil {
+						//	return err // we exit or bubble up a NACK...
+						//}
+						// Instead of doing the above, we can
+						// add events to a pending list, and
+						// when we finish the delay, we can run
+						// them.
+						//pendingSendEvent = true // all events are identical for now...
+					}
+				}
+			}
+			timer.Stop() // it's nice to cleanup
+			log.Printf("%s: Watch delay expired!", obj)
+			// NOTE: we can avoid the send if running Watch guarantees
+			// one CheckApply event on startup!
+			//if pendingSendEvent { // TODO: should this become a list in the future?
+			//	if err := obj.Event() err != nil {
+			//		return err // we exit or bubble up a NACK...
+			//	}
+			//}
+		}
+
+		// TODO: reset the watch retry count after some amount of success
+		var e error
+		if obj.Meta().Poll > 0 { // poll instead of watching :(
+			obj.cuid.StartTimer()
+			e = obj.Poll()
+			obj.cuid.StopTimer() // clean up nicely
+		} else {
+			e = obj.Res.Watch() // run the watch normally
+		}
+		if e == nil { // exit signal
+			err = nil // clean exit
+			break
+		}
+		if sentinelErr, ok := e.(*SentinelErr); ok { // unwrap the sentinel
+			err = sentinelErr.err
+			break // sentinel means, perma-exit
+		}
+		log.Printf("%s: Watch errored: %v", obj, e)
+		if watchRetry == 0 {
+			err = fmt.Errorf("Permanent watch error: %v", e)
+			break
+		}
+		if watchRetry > 0 { // don't decrement the -1
+			watchRetry--
+		}
+		watchDelay = time.Duration(obj.Meta().Delay) * time.Millisecond
+		log.Printf("%s: Watch: Retrying after %.4f seconds (%d left)", obj, watchDelay.Seconds(), watchRetry)
+		// We need to trigger a CheckApply after Watch restarts, so that
+		// we catch any lost events that happened while down. We do this
+		// by getting the Watch resource to send one event once it's up!
+		//v.SendEvent(eventPoke, false, false)
+	}
+
+	obj.ProcessExit()
+	// close resource and return possible errors if any
+	if e := obj.Res.Close(); err == nil {
+		err = e
+	} else if e != nil {
+		err = multierr.Append(err, e) // list of errors
+	}
+	return err
+}

resources/augeas.go

@@ -0,0 +1,298 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+// +build !noaugeas
+
+package resources
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strings"
+
+	"github.com/purpleidea/mgmt/recwatch"
+
+	errwrap "github.com/pkg/errors"
+	// FIXME: we vendor go/augeas because master requires augeas 1.6.0
+	// and libaugeas-dev-1.6.0 is not yet available in a PPA.
+	"honnef.co/go/augeas"
+)
+
+const (
+	// NS is a namespace for augeas operations
+	NS = "Xmgmt"
+)
+
+func init() {
+	RegisterResource("augeas", func() Res { return &AugeasRes{} })
+}
+
+// AugeasRes is a resource that enables you to use the augeas resource.
+// Currently only allows you to change simple files (e.g sshd_config).
+type AugeasRes struct {
+	BaseRes `yaml:",inline"`
+
+	// File is the path to the file targeted by this resource.
+	File string `yaml:"file"`
+
+	// Lens is the lens used by this resource. If specified, mgmt
+	// will lower the augeas overhead by only loading that lens.
+	Lens string `yaml:"lens"`
+
+	// Sets is a list of changes that will be applied to the file, in the form of
+	// ["path", "value"]. mgmt will run augeas.Get() before augeas.Set(), to
+	// prevent changing the file when it is not needed.
+	Sets []AugeasSet `yaml:"sets"`
+
+	recWatcher *recwatch.RecWatcher // used to watch the changed files
+}
+
+// AugeasSet represents a key/value pair of settings to be applied.
+type AugeasSet struct {
+	Path  string `yaml:"path"`  // The relative path to the value to be changed.
+	Value string `yaml:"value"` // The value to be set on the given Path.
+}
+
+// Default returns some sensible defaults for this resource.
+func (obj *AugeasRes) Default() Res {
+	return &AugeasRes{
+		BaseRes: BaseRes{
+			MetaParams: DefaultMetaParams, // force a default
+		},
+	}
+}
+
+// Validate if the params passed in are valid data.
+func (obj *AugeasRes) Validate() error {
+	if !strings.HasPrefix(obj.File, "/") {
+		return fmt.Errorf("the File param should start with a slash")
+	}
+	if obj.Lens != "" && !strings.HasSuffix(obj.Lens, ".lns") {
+		return fmt.Errorf("the Lens param should have a .lns suffix")
+	}
+	if (obj.Lens == "") != (obj.File == "") {
+		return fmt.Errorf("the File and Lens params must be specified together")
+	}
+	return obj.BaseRes.Validate()
+}
+
+// Init initiates the resource.
+func (obj *AugeasRes) Init() error {
+	return obj.BaseRes.Init() // call base init, b/c we're overriding
+}
+
+// Watch is the primary listener for this resource and it outputs events.
+// Taken from the File resource.
+// FIXME: DRY - This is taken from the file resource
+func (obj *AugeasRes) Watch() error {
+	var err error
+	obj.recWatcher, err = recwatch.NewRecWatcher(obj.File, false)
+	if err != nil {
+		return err
+	}
+	defer obj.recWatcher.Close()
+
+	// notify engine that we're running
+	if err := obj.Running(); err != nil {
+		return err // bubble up a NACK...
+	}
+
+	var send = false // send event?
+	var exit *error
+
+	for {
+		if obj.debug {
+			log.Printf("%s: Watching: %s", obj, obj.File) // attempting to watch...
+		}
+
+		select {
+		case event, ok := <-obj.recWatcher.Events():
+			if !ok { // channel shutdown
+				return nil
+			}
+			if err := event.Error; err != nil {
+				return errwrap.Wrapf(err, "Unknown %s watcher error", obj)
+			}
+			if obj.debug { // don't access event.Body if event.Error isn't nil
+				log.Printf("%s: Event(%s): %v", obj, event.Body.Name, event.Body.Op)
+			}
+			send = true
+			obj.StateOK(false) // dirty
+
+		case event := <-obj.Events():
+			if exit, send = obj.ReadEvent(event); exit != nil {
+				return *exit // exit
+			}
+			//obj.StateOK(false) // dirty // these events don't invalidate state
+		}
+
+		// do all our event sending all together to avoid duplicate msgs
+		if send {
+			send = false
+			obj.Event()
+		}
+	}
+}
+
+// checkApplySet runs CheckApply for one element of the AugeasRes.Set
+func (obj *AugeasRes) checkApplySet(apply bool, ag *augeas.Augeas, set AugeasSet) (bool, error) {
+	fullpath := fmt.Sprintf("/files/%v/%v", obj.File, set.Path)
+
+	// We do not check for errors because errors are also thrown when
+	// the path does not exist.
+	if getValue, _ := ag.Get(fullpath); set.Value == getValue {
+		// The value is what we expect, return directly
+		return true, nil
+	}
+
+	if !apply {
+		// If noop, we can return here directly. We return with
+		// nil even if err is not nil because it does not mean
+		// there is an error.
+		return false, nil
+	}
+
+	if err := ag.Set(fullpath, set.Value); err != nil {
+		return false, errwrap.Wrapf(err, "augeas: error while setting value")
+	}
+
+	return false, nil
+}
+
+// CheckApply method for Augeas resource.
+func (obj *AugeasRes) CheckApply(apply bool) (bool, error) {
+	log.Printf("%s: CheckApply: %s", obj, obj.File)
+	// By default we do not set any option to augeas, we use the defaults.
+	opts := augeas.None
+	if obj.Lens != "" {
+		// if the lens is specified, we can speed up augeas by not
+		// loading everything. Without this option, augeas will try to
+		// read all the files it knows in the complete filesystem.
+		// e.g. to change /etc/ssh/sshd_config, it would load /etc/hosts, /etc/ntpd.conf, etc...
+		opts = augeas.NoModlAutoload
+	}
+
+	// Initiate augeas
+	ag, err := augeas.New("/", "", opts)
+	if err != nil {
+		return false, errwrap.Wrapf(err, "augeas: error while initializing")
+	}
+	defer ag.Close()
+
+	if obj.Lens != "" {
+		// If the lens is set, load the lens for the file we want to edit.
+		// We pick Xmgmt, as this name will not collide with any other lens name.
+		// We do not pick Mgmt as in the future there might be an Mgmt lens.
+		// https://github.com/hercules-team/augeas/wiki/Loading-specific-files
+		if err = ag.Set(fmt.Sprintf("/augeas/load/%s/lens", NS), obj.Lens); err != nil {
+			return false, errwrap.Wrapf(err, "augeas: error while initializing lens")
+		}
+		if err = ag.Set(fmt.Sprintf("/augeas/load/%s/incl", NS), obj.File); err != nil {
+			return false, errwrap.Wrapf(err, "augeas: error while initializing incl")
+		}
+		if err = ag.Load(); err != nil {
+			return false, errwrap.Wrapf(err, "augeas: error while loading")
+		}
+	}
+
+	checkOK := true
+	for _, set := range obj.Sets {
+		if setCheckOK, err := obj.checkApplySet(apply, &ag, set); err != nil {
+			return false, errwrap.Wrapf(err, "augeas: error during CheckApply of one Set")
+		} else if !setCheckOK {
+			checkOK = false
+		}
+	}
+
+	// If the state is correct or we can't apply, return early.
+	if checkOK || !apply {
+		return checkOK, nil
+	}
+
+	log.Printf("%s: changes needed, saving", obj)
+	if err = ag.Save(); err != nil {
+		return false, errwrap.Wrapf(err, "augeas: error while saving augeas values")
+	}
+
+	// FIXME: Workaround for https://github.com/dominikh/go-augeas/issues/13
+	// To be fixed upstream.
+	if obj.File != "" {
+		if _, err := os.Stat(obj.File); os.IsNotExist(err) {
+			return false, errwrap.Wrapf(err, "augeas: error: file does not exist")
+		}
+	}
+
+	return false, nil
+}
+
+// AugeasUID is the UID struct for AugeasRes.
+type AugeasUID struct {
+	BaseUID
+	name string
+}
+
+// UIDs includes all params to make a unique identification of this object.
+func (obj *AugeasRes) UIDs() []ResUID {
+	x := &AugeasUID{
+		BaseUID: BaseUID{Name: obj.GetName(), Kind: obj.GetKind()},
+		name:    obj.Name,
+	}
+	return []ResUID{x}
+}
+
+// GroupCmp returns whether two resources can be grouped together or not.
+func (obj *AugeasRes) GroupCmp(r Res) bool {
+	return false // Augeas commands can not be grouped together.
+}
+
+// Compare two resources and return if they are equivalent.
+func (obj *AugeasRes) Compare(r Res) bool {
+	// we can only compare AugeasRes to others of the same resource kind
+	res, ok := r.(*AugeasRes)
+	if !ok {
+		return false
+	}
+	if !obj.BaseRes.Compare(res) { // call base Compare
+		return false
+	}
+	if obj.Name != res.Name {
+		return false
+	}
+
+	return true
+}
+
+// UnmarshalYAML is the custom unmarshal handler for this struct.
+// It is primarily useful for setting the defaults.
+func (obj *AugeasRes) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	type rawRes AugeasRes // indirection to avoid infinite recursion
+
+	def := obj.Default()        // get the default
+	res, ok := def.(*AugeasRes) // put in the right format
+	if !ok {
+		return fmt.Errorf("could not convert to AugeasRes")
+	}
+	raw := rawRes(*res) // convert; the defaults go here
+
+	if err := unmarshal(&raw); err != nil {
+		return err
+	}
+
+	*obj = AugeasRes(raw) // restore from indirection with type conversion!
+	return nil
+}

resources/augeas_disabled.go

@@ -0,0 +1,25 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+// +build noaugeas
+
+package resources
+
+// AugeasRes represents the fields of the Augeas resource. Since this file is
+// only invoked with the tag "noaugeas", we do not need any fields here.
+type AugeasRes struct {
+}