graceful shutdown blocks from shutting down on close

main.go

package main

import (
	"flag"
)

var (
	listenAddr string
)

func main() {
	flag.StringVar(&listenAddr, "listen-addr", ":5000", "server listen address")
	flag.Parse()

	server, err := NewServer(listenAddr)
	if err != nil {
		panic(err)
	}
	server.Start()
}

server.go

package main

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

// Server provides an http.Server
type Server struct {
	log *log.Logger
	*http.Server
}

// NewServer creates and configures an APIServer serving all application routes.
func NewServer(listenAddr string) (*Server, error) {
	logger := log.New(os.Stdout, "http: ", log.LstdFlags)

	api := http.NewServeMux()
	api.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		io.WriteString(w, "Hello World\n")
	})

	srv := http.Server{
		Addr:         listenAddr,
		Handler:      api,
		ErrorLog:     logger,
		ReadTimeout:  5 * time.Second,
		WriteTimeout: 10 * time.Second,
		IdleTimeout:  15 * time.Second,
	}

	return &Server{logger, &srv}, nil
}

// Start runs ListenAndServe on the http.Server with graceful shutdown
func (srv *Server) Start() {
	srv.log.Println("Starting server...")

	done := make(chan bool, 1)
	go srv.gracefullShutdown(done)
	srv.log.Println("Gracefull shutdown interupt signal registered")
	// code below will not run until interupt signal is given using ctrl+c
	srv.log.Println("Server is ready to handle requests at", srv.Addr)

	go func() {
		time.Sleep(5 * time.Second)
		srv.Close()
	}()

	if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
		srv.log.Fatalf("Could not listen on %s: %v\n", srv.Addr, err)
	}

	//<-done
	srv.log.Println("Server stopped")
}

func (srv *Server) gracefullShutdown(done chan<- bool) {
	quit := make(chan os.Signal)

	signal.Notify(quit, os.Interrupt)
	sig := <-quit
	srv.log.Println("Server is shutting down... Reason:", sig)

	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	srv.SetKeepAlivesEnabled(false)
	if err := srv.Shutdown(ctx); err != nil {
		srv.log.Fatalf("Could not gracefully shutdown the server: %v\n", err)
	}
	close(done)
}