Graceful Shutdown Context Signal

package main

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

func main() {
	mux := http.NewServeMux()
	mux.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprintln(w, "ok")
	})

	srv := &http.Server{
		Addr:              ":8080",
		Handler:           mux,
		ReadHeaderTimeout: 5 * time.Second,
	}

	ctx, stop := signal.NotifyContext(
		context.Background(), syscall.SIGTERM, syscall.SIGINT,
	)
	defer stop()

	go func() {
		if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
			log.Fatalf("serve: %v", err)
		}
	}()

	<-ctx.Done() // 阻塞直到收到终止信号
	log.Println("shutdown signal received, draining")

	shutdownCtx, cancel := context.WithTimeout(context.Background(), 25*time.Second)
	defer cancel()

	if err := srv.Shutdown(shutdownCtx); err != nil {
		log.Printf("forced close after deadline: %v", err)
	}
	log.Println("server stopped cleanly")
}