b19583e7d3
This is an initial implementation of the mgmt language. It is a declarative (immutable) functional, reactive, domain specific programming language. It is intended to be a language that is: * safe * powerful * easy to reason about With these properties, we hope this language, and the mgmt engine will allow you to model the real-time systems that you'd like to automate. This also includes a number of other associated changes. Sorry for the large size of this patch.
81 lines
3.1 KiB
Go
81 lines
3.1 KiB
Go
// Mgmt
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// Copyright (C) 2013-2018+ James Shubin and the project contributors
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// Written by James Shubin <james@shubin.ca> and the project contributors
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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// Package gapi defines the interface that graph API generators must meet.
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package gapi
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import (
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"encoding/gob"
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"fmt"
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"github.com/purpleidea/mgmt/pgraph"
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"github.com/purpleidea/mgmt/resources"
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"github.com/urfave/cli"
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)
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// RegisteredGAPIs is a global map of all possible GAPIs which can be used. You
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// should never touch this map directly. Use methods like Register instead.
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var RegisteredGAPIs = make(map[string]func() GAPI) // must initialize this map
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// Register takes a GAPI and its name and makes it available for use. There is
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// no matching Unregister function.
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func Register(name string, fn func() GAPI) {
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if _, ok := RegisteredGAPIs[name]; ok {
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panic(fmt.Sprintf("a GAPI named %s is already registered", name))
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}
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gob.Register(fn())
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RegisteredGAPIs[name] = fn
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}
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// Data is the set of input values passed into the GAPI structs via Init.
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type Data struct {
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Program string // name of the originating program
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Hostname string // uuid for the host, required for GAPI
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World resources.World
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Noop bool
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NoConfigWatch bool
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NoStreamWatch bool
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Debug bool
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Logf func(format string, v ...interface{})
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// NOTE: we can add more fields here if needed by GAPI endpoints
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}
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// Next describes the particular response the GAPI implementer wishes to emit.
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type Next struct {
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// FIXME: the Fast pause parameter should eventually get replaced with a
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// "SwitchMethod" parameter or similar that instead lets the implementer
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// choose between fast pause, slow pause, and interrupt. Interrupt could
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// be a future extension to the Resource API that lets an Interrupt() be
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// called if we want to exit immediately from the CheckApply part of the
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// resource for some reason. For now we'll keep this simple with a bool.
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Fast bool // run a fast pause to switch?
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Exit bool // should we cause the program to exit? (specify err or not)
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Err error // if something goes wrong (use with or without exit!)
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}
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// GAPI is a Graph API that represents incoming graphs and change streams.
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type GAPI interface {
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Cli(c *cli.Context, fs resources.Fs) (*Deploy, error)
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CliFlags() []cli.Flag
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Init(Data) error // initializes the GAPI and passes in useful data
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Graph() (*pgraph.Graph, error) // returns the most recent pgraph
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Next() chan Next // returns a stream of switch events
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Close() error // shutdown the GAPI
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}
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