Minimal code needed to implement graceful shutdown of HTTP server in Go 1.8 and up.

shutdown.go

package main

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

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte("Hello World!"))
	})

	// This server will use http.DefaultServeMux, set Handler here to override.
	server := &http.Server{Addr: ":8080"}

	// Serve HTTP connections and wait for server to close.
	done := make(chan bool, 1)
	go func() {
		log.Printf("Serving on %s...", server.Addr)
		if err := server.ListenAndServe(); err != http.ErrServerClosed {
			log.Printf("Failed to serve HTTP: %v", err)
			done <- true
		}
	}()

	// Listen for signals to shut down server.
	go func() {
		c := make(chan os.Signal, 1)
		signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
		<-c
		// We received interrupt/terminate signal, don't listen for more.
		signal.Stop(c)
		log.Printf("Shutting down...")
		// Shut down the HTTP server (this won't wait for hijacked connections).
		ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
		defer cancel()
		if err := server.Shutdown(ctx); err != nil {
			log.Printf("Failed to shut down HTTP server gracefully: %v", err)
			// Force kill connections instead.
			if err := server.Close(); err != nil {
				log.Printf("Additionally, received error when closing: %v", err)
			}
		}
		// Tell the main thread that we're done.
		done <- true
	}()

	// Wait for server to stop serving.
	<-done

	// TODO: Put your other shutdown logic here.
	// ...

	log.Println("Good bye!")
}