25ad05cce3
This is a prototype that i'm attempting to "release early". Expect a lot of changes! It is intended to be a config management tool that will: * be event based * execute actions in parallel * function as a distributed system There are a bunch more design ideas going into this, please stay tuned!
148 lines
3.5 KiB
Go
148 lines
3.5 KiB
Go
// Mgmt
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// Copyright (C) 2013-2015+ 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 Affero 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 Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package main
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import (
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"fmt"
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"github.com/codegangsta/cli"
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"log"
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"os"
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"os/signal"
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"sync"
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"syscall"
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"time"
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)
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// set at compile time
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var (
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version string
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program string
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)
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const (
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DEBUG = false
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)
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// signal handler
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func waitForSignal(exit chan bool) {
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signals := make(chan os.Signal, 1)
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signal.Notify(signals, os.Interrupt) // catch ^C
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//signal.Notify(signals, os.Kill) // catch signals
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signal.Notify(signals, syscall.SIGTERM)
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select {
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case e := <-signals: // any signal will do
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if e == os.Interrupt {
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fmt.Println() // put ^C char from terminal on its own line
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log.Println("Interrupted by ^C")
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} else {
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log.Println("Interrupted by signal")
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}
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case <-exit: // or a manual signal
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log.Println("Interrupted by exit signal")
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}
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}
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func run(c *cli.Context) {
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var start int64 = time.Now().UnixNano()
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var wg sync.WaitGroup
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exit := make(chan bool) // exit signal
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log.Printf("This is: %v, version: %v\n", program, version)
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// exit after `exittime` seconds for no reason at all...
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if i := c.Int("exittime"); i > 0 {
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go func() {
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time.Sleep(time.Duration(i) * time.Second)
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exit <- true
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}()
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}
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// build the graph from a config file
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G := GraphFromConfig(c.String("file"))
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log.Printf("Graph: %v\n", G) // show graph
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log.Printf("Start: %v\n", start)
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for x := range G.GetVerticesChan() { // XXX ?
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log.Printf("Main->Starting[%v]\n", x.Name)
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wg.Add(1)
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// must pass in value to avoid races...
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// see: https://ttboj.wordpress.com/2015/07/27/golang-parallelism-issues-causing-too-many-open-files-error/
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go func(v *Vertex) {
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defer wg.Done()
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v.Start()
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log.Printf("Main->Finish[%v]\n", v.Name)
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}(x)
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// generate a startup "poke" so that an initial check happens
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go func(v *Vertex) {
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v.Events <- fmt.Sprintf("Startup(%v)", v.Name)
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}(x)
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}
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log.Println("Running...")
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waitForSignal(exit) // pass in exit channel to watch
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G.Exit() // tell all the children to exit
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if DEBUG {
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for i := range G.GetVerticesChan() {
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fmt.Printf("Vertex: %v\n", i)
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}
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fmt.Printf("Graph: %v\n", G)
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}
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wg.Wait() // wait for primary go routines to exit
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// TODO: wait for each vertex to exit...
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log.Println("Goodbye!")
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}
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func main() {
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app := cli.NewApp()
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app.Name = program
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app.Usage = "next generation config management"
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app.Version = version
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//app.Action = ... // without a default action, help runs
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app.Commands = []cli.Command{
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{
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Name: "run",
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Aliases: []string{"r"},
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Usage: "run",
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Action: run,
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Flags: []cli.Flag{
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cli.StringFlag{
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Name: "file, f",
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Value: "",
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Usage: "graph definition to run",
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},
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cli.IntFlag{
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Name: "exittime",
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Value: 0,
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Usage: "exit after a maximum of approximately this many seconds",
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},
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},
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},
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}
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app.EnableBashCompletion = true
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app.Run(os.Args)
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}
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