From 5fefa8af6298d5cc62c996dc8611c2224bb30471 Mon Sep 17 00:00:00 2001
From: PratikDhanave <i.pratikdhanave@gmail.com>
Date: Sun, 1 Nov 2020 16:05:04 +0530
Subject: [PATCH] graceful shutdown allows to server to wait for 10 sec to
 finish work

---
 main.go | 53 +++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 47 insertions(+), 6 deletions(-)

diff --git a/main.go b/main.go
index 2e6cef7..cdb1398 100644
--- a/main.go
+++ b/main.go
@@ -1,6 +1,13 @@
 package main
 
 import (
+	"context"
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
 	"ukiyo/pkg/apilayer"
 	"ukiyo/pkg/webhooks"
 
@@ -8,10 +15,44 @@ import (
 )
 
 func main() {
-	r := gin.Default()
-	webhooks.HooksListener(r)
-	webhooks.HealthCheck(r)
-	apilayer.AddContainer(r)
-	apilayer.EditContainerToken(r)
-	r.Run(":8080")
+	router := gin.Default()
+
+	webhooks.HooksListener(router)
+	webhooks.HealthCheck(router)
+	apilayer.AddContainer(router)
+	apilayer.EditContainerToken(router)
+
+	srv := &http.Server{
+		Addr:    ":8080",
+		Handler: router,
+	}
+
+	// Initializing the server in a goroutine so that
+	// it won't block the graceful shutdown handling below
+	go func() {
+		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			log.Fatalf("listen: %s\n", err)
+		}
+	}()
+
+	// Wait for interrupt signal to gracefully shutdown the server with
+	// a timeout of 5 seconds.
+	quit := make(chan os.Signal)
+	// kill (no param) default send syscall.SIGTERM
+	// kill -2 is syscall.SIGINT
+	// kill -9 is syscall.SIGKILL but can't be catch, so don't need add it
+	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
+	<-quit
+	log.Println("ukiyo Shutting down server...")
+
+	// The context is used to inform the server it has 10 seconds to finish
+	// the request it is currently handling
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	if err := srv.Shutdown(ctx); err != nil {
+		log.Fatal("ukiyo Server forced to shutdown:", err)
+	}
+
+	log.Println("ukiyo Server exiting")
+
 }