Files
mgmt/gapi/gapi.go
James Shubin cd7711bdfe gapi: Add a prefix variable in case we want to namespace on disk
This could get passed through to use as a module download path.
2018-12-20 21:21:30 -05:00

82 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
Prefix string
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
}