Golang | Graceful shutdown

https://play.golang.org/p/3VWgxtuzLIs
package main

import (
    "log"
    "os"
    "os/signal"
    "syscall"
    "time"
)

type Cmd struct {
    Closed chan struct{}
}

func (c *Cmd) Close() {
    log.Println("closing program...")
    // wait for program to clean up nicely
    time.Sleep(5 * time.Second)
    log.Println("closed program")
    close(c.Closed)
}

// section: main
func main() {
    cmd := Cmd{Closed: make(chan struct{})}

    signalCh := make(chan os.Signal, 1)
    signal.Notify(signalCh, os.Interrupt, syscall.SIGTERM)
    log.Println("Listening for signals")

    // Block until one of the signals above is received
    <-signalCh
    log.Println("Signal received, initializing clean shutdown...")
    go cmd.Close()

    // Block again until another signal is received, a shutdown timeout elapses,
    // or the Command is gracefully closed
    log.Println("Waiting for clean shutdown...")
    select {
    case <-signalCh:
        log.Println("second signal received, initializing hard shutdown")
    case <-time.After(time.Second * 30):
        log.Println("time limit reached, initializing hard shutdown")
    case <-cmd.Closed:
        log.Println("server shutdown completed")
    }

    // goodbye.
}

// section: main
deoren / notes

Golang | Graceful shutdown #61
