Files
mgmt/gapi/gapi.go
James Shubin 9969286224 engine: Resources package rewrite
This giant patch makes some much needed improvements to the code base.

* The engine has been rewritten and lives within engine/graph/
* All of the common interfaces and code now live in engine/
* All of the resources are in one package called engine/resources/
* The Res API can use different "traits" from engine/traits/
* The Res API has been simplified to hide many of the old internals
* The Watch & Process loops were previously inverted, but is now fixed
* The likelihood of package cycles has been reduced drastically
* And much, much more...

Unfortunately, some code had to be temporarily removed. The remote code
had to be taken out, as did the prometheus code. We hope to have these
back in new forms as soon as possible.
2018-04-19 01:10:58 -04:00

81 lines
3.1 KiB
Go

// Mgmt
// Copyright (C) 2013-2018+ 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 gapi defines the interface that graph API generators must meet.
package gapi
import (
"encoding/gob"
"fmt"
"github.com/purpleidea/mgmt/engine"
"github.com/purpleidea/mgmt/pgraph"
"github.com/urfave/cli"
)
// RegisteredGAPIs is a global map of all possible GAPIs which can be used. You
// should never touch this map directly. Use methods like Register instead.
var RegisteredGAPIs = make(map[string]func() GAPI) // must initialize this map
// Register takes a GAPI and its name and makes it available for use. There is
// no matching Unregister function.
func Register(name string, fn func() GAPI) {
if _, ok := RegisteredGAPIs[name]; ok {
panic(fmt.Sprintf("a GAPI named %s is already registered", name))
}
gob.Register(fn())
RegisteredGAPIs[name] = fn
}
// Data is the set of input values passed into the GAPI structs via Init.
type Data struct {
Program string // name of the originating program
Hostname string // uuid for the host, required for GAPI
World engine.World
Noop bool
NoConfigWatch bool
NoStreamWatch bool
Debug bool
Logf func(format string, v ...interface{})
// 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 {
Cli(c *cli.Context, fs engine.Fs) (*Deploy, error)
CliFlags() []cli.Flag
Init(Data) error // initializes the GAPI and passes in useful data
Graph() (*pgraph.Graph, error) // returns the most recent pgraph
Next() chan Next // returns a stream of switch events
Close() error // shutdown the GAPI
}