Shutdown HTTP server by requesting specific URL in Golang

main.go

package main

import (
	"context"
	"fmt"
	"log"
	"net/http"
)

func main() {
	m := http.NewServeMux()
	s := http.Server{Addr: ":8000", Handler: m}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	m.Handle("/", &myHandler{cancel})

	go func() {
		log.Printf("Starting server on port 8000")
		if err := s.ListenAndServe(); err != nil {
			if err != http.ErrServerClosed {
				log.Fatal(err)
			}
		}
	}()

	select {
	case <-ctx.Done():
		log.Printf("Shutting down server")
		s.Shutdown(ctx)
	}
}

type myHandler struct {
	cancel context.CancelFunc
}

func (s *myHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	switch r.URL.Path {
	case "/shutdown":
		log.Printf("Shutdown requested")
		fmt.Fprint(w, "OK")
		s.cancel()
	default:
		fmt.Fprint(w, "OK")
	}
}