httpdshutdown

Count connections to permit daemons to stop safely, and run hooks at shutdown time.

NOTE

As of early 2017, the Go standard library includes some of this functionality in the standard net/http library. You might want to check that first.

EXAMPLE

package main

import (
    "log"
	"net"
	"net/http"
	"github.com/bradclawsie/httpdshutdown"
	"os"
	"os/signal"
	"time"
)

func sampleShutdownHook1() error {
	log.Println("shutdown hook 1 called")
	return nil
}

func sampleShutdownHook2() error {
	log.Println("shutdown hook 2 called")
	return nil
}

func main() {
	log.Printf("launching with pid:%d\n", os.Getpid())
	watcher, watcher_err := httpdshutdown.NewWatcher(2000, sampleShutdownHook1, sampleShutdownHook2)
	if watcher == nil || watcher_err != nil {
		panic("could not construct watcher")
	}

	// Launch the signal handler and exit logic in a goroutine since the http daemon
	// issued later will run in the foreground.
	go func() {
		sigs := make(chan os.Signal, 1)
		exitcode := make(chan int, 1)
		signal.Notify(sigs)
		go watcher.SigHandle(sigs, exitcode)
		code := <-exitcode
		log.Printf("exit with code:%d", code)
		os.Exit(code)
	}()

	srv := &http.Server{
		Addr: ":8080",
		ReadTimeout:  3 * time.Second,
		WriteTimeout: 3 * time.Second,
		ConnState: func(conn net.Conn, newState http.ConnState) {
			log.Printf("(1) NEW CONN STATE:%v\n", newState)
			watcher.RecordConnState(newState)
			return
		},
	}

	log.Fatal(srv.ListenAndServe())
}