graceful listen and serve

graceful.go

func GracefullyListenAndServe(ctx context.Context, servePort string, rtr *mux.Router) {
	http.Handle("/", rtr)

	h := &http.Server{
		Addr:              fmt.Sprintf(":%v", servePort),
		Handler:           handlers.CORS()(rtr),
	}

	sig := make(chan os.Signal, 1)

	signal.Notify(sig, os.Interrupt)
	signal.Notify(sig, syscall.SIGTERM)

	go func() {
		log.Printf("serving on port: %v", servePort)
		if err := h.ListenAndServe(); err != nil {
			log.Fatalf("%v", err)
		}
	}()

	// wait for signal to end
	<-sig

	log.Println("Shutting down server...")

	_ = h.Shutdown(ctx)

	log.Println("server gracefully shutdown")
}