Merge pull request #24 from EmileVauge/zero-downtime-reload

Zero downtime reload

Godeps/Godeps.json

@@ -69,6 +69,11 @@
 			"ImportPath": "github.com/mailgun/log",
 			"Rev": "44874009257d4d47ba9806f1b7f72a32a015e4d8"
 		},
+		{
+			"ImportPath": "github.com/mailgun/manners",
+			"Comment": "0.3.1-30-g37136f7",
+			"Rev": "37136f736785d7c6aa3b9a27b4b2dd1028ca6d79"
+		},
 		{
 			"ImportPath": "github.com/mailgun/oxy/cbreaker",
 			"Rev": "547c334d658398c05b346c0b79d8f47ba2e1473b"
@@ -101,19 +106,10 @@
 			"ImportPath": "github.com/thoas/stats",
 			"Rev": "54ed61c2b47e263ae2f01b86837b0c4bd1da28e8"
 		},
-		{
-			"ImportPath": "github.com/tylerb/graceful",
-			"Comment": "v1.2.1",
-			"Rev": "ac9ebe4f1ee151ac1eeeaef32957085cba64d508"
-		},
 		{
 			"ImportPath": "github.com/unrolled/render",
 			"Rev": "26b4e3aac686940fe29521545afad9966ddfc80c"
 		},
-		{
-			"ImportPath": "golang.org/x/net/netutil",
-			"Rev": "d9558e5c97f85372afee28cf2b6059d7d3818919"
-		},
 		{
 			"ImportPath": "gopkg.in/alecthomas/kingpin.v2",
 			"Comment": "v2.0.12",

README.md

@@ -38,7 +38,7 @@ Here is a demo of Træfɪk using Docker backend, showing a load-balancing betwee
 * [Oxy](https://github.com/mailgun/oxy/): an awsome proxy library made by Mailgun guys
 * [Gorilla mux](https://github.com/gorilla/mux): famous request router
 * [Negroni](https://github.com/codegangsta/negroni): web middlewares made simple
-* [Graceful](https://github.com/tylerb/graceful): graceful shutdown of http.Handler servers
+* [Manners](https://github.com/mailgun/manners): graceful shutdown of http.Handler servers
 
 # Quick start
 

traefik.go

@@ -17,13 +17,14 @@ import (
 	"github.com/codegangsta/negroni"
 	"github.com/emilevauge/traefik/middlewares"
 	"github.com/gorilla/mux"
+	"github.com/mailgun/manners"
 	"github.com/mailgun/oxy/cbreaker"
 	"github.com/mailgun/oxy/forward"
 	"github.com/mailgun/oxy/roundrobin"
 	"github.com/thoas/stats"
-	"github.com/tylerb/graceful"
 	"github.com/unrolled/render"
 	"gopkg.in/alecthomas/kingpin.v2"
+	"runtime"
 )
 
 var (
@@ -39,14 +40,18 @@ var (
 )
 
 func main() {
+	runtime.GOMAXPROCS(runtime.NumCPU())
 	kingpin.Parse()
 	fmtlog.SetFlags(fmtlog.Lshortfile | fmtlog.LstdFlags)
-	var srv *graceful.Server
+	var srv *manners.GracefulServer
 	var configurationRouter *mux.Router
 	var configurationChan = make(chan *Configuration, 10)
 	defer close(configurationChan)
-	var providers = []Provider{}
 	var sigs = make(chan os.Signal, 1)
+	defer close(sigs)
+	var stopChan = make(chan bool)
+	defer close(stopChan)
+	var providers = []Provider{}
 	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
 
 	// load global configuration
@@ -91,8 +96,15 @@ func main() {
 				if err == nil {
 					currentConfiguration = configuration
 					configurationRouter = newConfigurationRouter
-					srv.Stop(time.Duration(globalConfiguration.GraceTimeOut) * time.Second)
+					oldServer := srv
-					time.Sleep(3 * time.Second)
+					newsrv := prepareServer(configurationRouter, globalConfiguration, oldServer, loggerMiddleware, metrics)
+					go startServer(newsrv, globalConfiguration)
+					srv = newsrv
+					time.Sleep(2 * time.Second)
+					if oldServer != nil {
+						log.Info("Stopping old server")
+						oldServer.Close()
+					}
 				} else {
 					log.Error("Error loading new configuration, aborted ", err)
 				}
@@ -130,38 +142,25 @@ func main() {
 		}()
 	}
 
-	goAway := false
 	go func() {
 		sig := <-sigs
 		log.Infof("I have to go... %+v", sig)
-		goAway = true
+		log.Info("Stopping server")
-		srv.Stop(time.Duration(globalConfiguration.GraceTimeOut) * time.Second)
+		srv.Close()
+		stopChan <- true
 	}()
 
-	for {
-		if goAway {
-			break
-		}
-
-		// middlewares
-		var negroni = negroni.New()
-		negroni.Use(metrics)
-		negroni.Use(loggerMiddleware)
 	//negroni.Use(middlewares.NewCircuitBreaker(oxyLogger))
 	//negroni.Use(middlewares.NewRoutes(configurationRouter))
-		negroni.UseHandler(configurationRouter)
+	srv = prepareServer(configurationRouter, globalConfiguration, nil, loggerMiddleware, metrics)
+	go startServer(srv, globalConfiguration)
 
-		srv = &graceful.Server{
+	<-stopChan
-			Timeout:          time.Duration(globalConfiguration.GraceTimeOut) * time.Second,
+	log.Info("Shutting down")
-			NoSignalHandling: true,
+}
 
-			Server: &http.Server{
+func startServer(srv *manners.GracefulServer, globalConfiguration *GlobalConfiguration) {
-				Addr:    globalConfiguration.Port,
+	log.Info("Starting server")
-				Handler: negroni,
-			},
-		}
-
-		go func() {
 	if len(globalConfiguration.CertFile) > 0 && len(globalConfiguration.KeyFile) > 0 {
 		err := srv.ListenAndServeTLS(globalConfiguration.CertFile, globalConfiguration.KeyFile)
 		if err != nil {
@@ -179,10 +178,35 @@ func main() {
 			}
 		}
 	}
-		}()
+	log.Info("Server stopped")
-		log.Info("Started")
+}
-		<-srv.StopChan()
+
-		log.Info("Stopped")
+func prepareServer(router *mux.Router, globalConfiguration *GlobalConfiguration, oldServer *manners.GracefulServer, middlewares ...negroni.Handler) *manners.GracefulServer {
+	log.Info("Preparing server")
+	// middlewares
+	var negroni = negroni.New()
+	for _, middleware := range middlewares {
+		negroni.Use(middleware)
+	}
+	negroni.UseHandler(router)
+
+	if oldServer == nil {
+		return manners.NewWithServer(
+			&http.Server{
+				Addr:    globalConfiguration.Port,
+				Handler: negroni,
+			})
+	} else {
+		server, err := oldServer.HijackListener(&http.Server{
+			Addr:    globalConfiguration.Port,
+			Handler: negroni,
+		}, nil)
+		if err != nil {
+			log.Fatalf("Error hijacking server %s", err)
+			return nil
+		} else {
+			return server
+		}
 	}
 }