Go useful snippets

graceful-shutdown.go

func main() {
  // simple logger with time flag
	l := log.New(os.Stdout, "", log.LstdFlags)
  // handler
	h := http.NewServeMux()
  // h.Handle("/", handler.HelloWorld))
  
  // sever with standard setups
	s := http.Server{
		Addr:         addr,
		Handler:      h,
		ErrorLog:     l,
		ReadTimeout:  5 * time.Second,
		WriteTimeout: 10 * time.Second,
		IdleTimeout:  120 * time.Second,
	}

	// start the sever concurrently to not blocking below codes.
	go func() {
		l.Println("Sever running at", addr)
		l.Fatal(s.ListenAndServe())
	}()

	// graceful shutdown on system interrup or kill
	sig := make(chan os.Signal, 1)
	signal.Notify(sig, os.Interrupt, os.Kill)
  // wait for signal
	<-sig
	ctx, cancel := context.WithTimeout(context.Background(), time.Second*30)
	defer cancel()
	log.Println("Gracefully shutting down...")
  // shutdown sever with 30 seconds timeout
	_ = s.Shutdown(ctx)
}