compilation: virt: Make libvirt support optional

refs #114

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>

Makefile

@@ -37,6 +37,9 @@ 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
 
 #
 #	art
@@ -105,9 +108,9 @@ $(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 $(PROGRAM);
+	time go build -ldflags "-X main.program=$(PROGRAM) -X main.version=$(SVERSION)" -o $(PROGRAM) $(BUILD_FLAGS);
 endif
 
 $(PROGRAM).static: main.go

docs/documentation.md

@@ -42,6 +42,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 	* [Meta parameters](#meta-parameters)
 	* [Graph definition file](#graph-definition-file)
 	* [Command line](#command-line)
+	* [Compilation options](#compilation-options)
 8. [Examples - Example configurations](#examples)
 9. [Development - Background on module development and reporting bugs](#development)
 10. [Authors - Authors and contact information](#authors)
@@ -420,6 +421,7 @@ If you feel that a well used option needs documenting here, please patch it!
 * [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
 These meta parameters are special parameters (or properties) which can apply to
@@ -545,6 +547,18 @@ 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.
 
+### Compilation options
+
+You can control some compilation variables by using environment variables.
+
+#### Disable livirt support
+
+If you wish to compile mgmt without libvirt, you can use the following command:
+
+```
+GOTAGS=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:

resources/virt.go

@@ -14,6 +14,7 @@
 //
 // 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/>.
+// +build !novirt
 
 package resources
 

resources/virt_disabled.go

@@ -0,0 +1,24 @@
+// 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/>.
+// +build novirt
+
+package resources
+
+// VirtRes represents the fields of the Virt resource. Since this file is
+// only invoked with the tag "novirt", we do not need any fields here.
+type VirtRes struct {
+}