week03.go

package main

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

	"github.com/pkg/errors"
	"golang.org/x/sync/errgroup"
)

func main() {
	g, ctx := errgroup.WithContext(context.Background())

	mux := http.NewServeMux()
	mux.HandleFunc("/ping", func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte("pong"))
	})

	// 访问链接退出
	serverOut := make(chan struct{})
	mux.HandleFunc("/shutdown", func(w http.ResponseWriter, r *http.Request) {
		serverOut <- struct{}{}
	})

	server := http.Server{
		Handler: mux,
		Addr:    ":8080",
	}

	// 第一个协程,启动http监听服务
	g.Go(func() error {
		return server.ListenAndServe()
	})

	// 第二个协程,监听取消以及手动取消
	g.Go(func() error {
		select {
		case <-ctx.Done():
			log.Println("errgroup exit...")
		case <-serverOut:
			log.Println("server will out...")
		}
		// 接收到手动取消
		cancel, cancelFunc := context.WithCancel(ctx)
		defer cancelFunc()
		log.Println("shutting down server...")
		_ = server.Shutdown(cancel)
		return nil
	})

	// 第三个协程,接收信号量
	g.Go(func() error {
		quit := make(chan os.Signal, 0)
		signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)

		select {
		case <-ctx.Done():
			return ctx.Err()
		case sig := <-quit:
			return errors.Errorf("get os signal: %v", sig)
		}
	})

	fmt.Printf("errgroup exiting: %+v\n", g.Wait())
}