Using signal NotifyContext for graceful HTTP server shutdown in Golang

package main

import (
	"context"
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"
)

type app struct {
	server   *http.Server
	shutdown time.Duration
}

func (a app) start() error {
	if err := a.server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
		return err
	}

	return nil
}

func (a app) stop(ctx context.Context) error {
	ctxNotify, stop := signal.NotifyContext(ctx, os.Interrupt, syscall.SIGTERM)
	<-ctxNotify.Done()
	stop()

	ctxTimeout, cancel := context.WithTimeout(ctx, a.shutdown)
	defer cancel()

	if err := a.server.Shutdown(ctxTimeout); err != nil {
		return err
	}

	return nil
}

func main() {
	handler := http.DefaultServeMux
	handler.HandleFunc("/", home)

	server := &http.Server{
		Addr:    ":1234",
		Handler: handler,
	}

	app := app{
		server:   server,
		shutdown: time.Second * 5,
	}

	go func() {
		log.Println("app is running")

		if err := app.start(); err != nil {
			log.Println("app start:", err)

			return
		}
	}()

	if err := app.stop(context.Background()); err != nil {
		log.Println("dirty app stop with possible interruptions:", err)
	} else {
		log.Println("clean app stop without any interruption")
	}
}

func home(w http.ResponseWriter, r *http.Request) {
	log.Println("in")
	time.Sleep(time.Second * 10) <- Adjust this in tests
	log.Println("out")
}

time.Sleep(time.Second * 2)

$ go run -race main.go
2024/01/21 14:02:14 app is running

2024/01/21 14:02:35 in
^C
2024/01/21 14:02:37 out
2024/01/21 14:02:37 clean app stop without any interruption

time.Sleep(time.Second * 8)

$ go run -race main.go
2024/01/21 14:03:28 app is running

2024/01/21 14:03:32 in
^C
2024/01/21 14:03:37 dirty app stop with possible interruptions: context deadline exceeded