update readme graceful shutdown example

README.md

@@ -1257,7 +1257,7 @@ func main() {
 	router.StaticFS("/more_static", http.Dir("my_file_system"))
 	router.StaticFile("/favicon.ico", "./resources/favicon.ico")
 	router.StaticFileFS("/more_favicon.ico", "more_favicon.ico", http.Dir("my_file_system"))
-	
+
 	// Listen and serve on 0.0.0.0:8080
 	router.Run(":8080")
 }
@@ -1831,31 +1831,38 @@ func main() {
 		Handler: router,
 	}
 
-	// Initializing the server in a goroutine so that
+	// Receive another goroutine listen error
-	// it won't block the graceful shutdown handling below
+	serverError := make(chan error, 1)
-	go func() {
-		if err := srv.ListenAndServe(); err != nil && errors.Is(err, http.ErrServerClosed) {
-			log.Printf("listen: %s\n", err)
-		}
-	}()
 
 	// Wait for interrupt signal to gracefully shutdown the server with
 	// a timeout of 5 seconds.
-	quit := make(chan os.Signal)
+	quit := make(chan os.Signal, 1)
+
+	// Initializing the server in a goroutine so that
+	// it won't block the graceful shutdown handling below
+	go func() {
+		serverError <- srv.ListenAndServe()
+	}()
+
 	// kill (no param) default send syscall.SIGTERM
 	// kill -2 is syscall.SIGINT
 	// kill -9 is syscall.SIGKILL but can't be caught, so don't need to add it
 	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
-	<-quit
-	log.Println("Shutting down server...")
 
-	// The context is used to inform the server it has 5 seconds to finish
+	select {
-	// the request it is currently handling
+	case err := <-serverError:
-	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		log.Printf("listen: %s\n", err)
-	defer cancel()
+	case <-quit:
+		log.Println("Shutting down server...")
+		// The context is used to inform the server it has 5 seconds to finish
+		// the request it is currently handling
+		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
 
-	if err := srv.Shutdown(ctx); err != nil {
+		if err := srv.Shutdown(ctx); err != nil {
-		log.Fatal("Server forced to shutdown:", err)
+			srv.Close()
+			log.Fatal("Server forced to shutdown:", err)
+		}
 	}
 
 	log.Println("Server exiting")
@@ -2225,7 +2232,7 @@ or network CIDRs from where clients which their request headers related to clien
 IP can be trusted. They can be IPv4 addresses, IPv4 CIDRs, IPv6 addresses or
 IPv6 CIDRs.
 
-**Attention:** Gin trust all proxies by default if you don't specify a trusted 
+**Attention:** Gin trust all proxies by default if you don't specify a trusted
 proxy using the function above, **this is NOT safe**. At the same time, if you don't
 use any proxy, you can disable this feature by using `Engine.SetTrustedProxies(nil)`,
 then `Context.ClientIP()` will return the remote address directly to avoid some
@@ -2255,7 +2262,7 @@ func main() {
 ```
 
 **Notice:** If you are using a CDN service, you can set the `Engine.TrustedPlatform`
-to skip TrustedProxies check, it has a higher priority than TrustedProxies. 
+to skip TrustedProxies check, it has a higher priority than TrustedProxies.
 Look at the example below:
 ```go
 import (