add request reject handler on shutdown #1

examples/myhttpapp/README.md

@@ -3,12 +3,12 @@
 # Build & Run
 
 ```
-go build -o bin/myhttpapp ./cmd/
+go build -o ./bin/myhttpapp ./cmd
 ./bin/myhttpapp
 ```
 
 # Run
 
 ```
-go run cmd/main.go
+go run ./cmd
 ```

examples/myhttpapp/configs/local.json

@@ -3,7 +3,7 @@
   "server": {
     "port": 8080,
     "shutdown": {
-      "gracetime": 1
+      "gracetime": 100
     }
   },
   "log": {

pkg/cli/service.go

@@ -66,7 +66,7 @@ func (s *Service) Start() error {
 func (s *Service) Stop() error {
 	log.Info("Service#Stop enter")
 	defer log.Info("Service#Stop exit")
-	s.exitCh <- struct{}{}
+	close(s.exitCh)
 	return nil
 }
 

pkg/http/service/reject.go

@@ -0,0 +1,21 @@
+package service
+
+import (
+	"net/http"
+)
+
+type reject struct {
+	h    http.Handler
+	done chan struct{}
+}
+
+func (rj *reject) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	select {
+	case <-rj.done:
+		// header: Retry-After
+		w.WriteHeader(http.StatusServiceUnavailable)
+		w.Write([]byte{})
+	default:
+		rj.h.ServeHTTP(w, r)
+	}
+}

pkg/http/service/server.go

@@ -20,7 +20,8 @@ type Server struct {
 	router           *mux.Router
 	preempt          *negroni.Negroni
 	healthController *healthController
-	services         []Service
+	components       []Component
+	exitCh           chan struct{}
 }
 
 func NewServer(cfg *config.Config) *Server {
@@ -39,6 +40,7 @@ func NewServer(cfg *config.Config) *Server {
 		preempt:          preempt,
 		router:           mux.NewRouter(),
 		healthController: newHealthController(),
+		exitCh:           make(chan struct{}),
 	}
 }
 
@@ -71,14 +73,16 @@ func (s *Server) Stop() {
 	log.Info("Server#Stop enter")
 	defer log.Info("Server#Stop exit")
 
+	close(s.exitCh)
+
 	log.Info("Server#Stop server status set to down")
 	s.healthController.setStatusDown()
 
 	// Stop any long-running services within the app
-	if len(s.services) > 0 {
-		for _, sr := range s.services {
-			if err := sr.Stop(); err != nil {
-				log.Info("Server#Stop failed to stop a running service: %v", err)
+	if len(s.components) > 0 {
+		for _, comp := range s.components {
+			if err := comp.Stop(); err != nil {
+				log.Info("Server#Stop failed to stop a running component: %v", err)
 			}
 		}
 	}
@@ -122,15 +126,18 @@ func (s *Server) setupBuildInfoEndpoints() {
 // preHandlers can be optionally supplied, they will run before routeHandler in the order supplied
 func (s *Server) Register(path, method string, routeHandler http.Handler, preHandlers ...negroni.Handler) {
 	chain := negroni.New(preHandlers...)
-	chain.UseHandler(routeHandler)
+	chain.UseHandler(&reject{
+		h:    routeHandler,
+		done: s.exitCh,
+	})
 	path = "/" + strings.TrimLeft(path, "/")
 	if err := s.router.Handle(path, chain).Methods(method).GetError(); err != nil {
 		log.Panic("Server#Register error %v building route for %v", err.Error(), path)
 	}
 	log.Info("Server#Register route [%v]%v registered", method, path)
 }
 
-// Service registers service that will run within the app that requires stopping when server shuts down
-func (s *Server) Service(sr Service) {
-	s.services = append(s.services, sr)
+// Component registers a Component that will run within the app that requires stopping when server shuts down
+func (s *Server) Component(comp Component) {
+	s.components = append(s.components, comp)
 }

pkg/http/service/service.go

@@ -1,7 +1,7 @@
 package service
 
-// Service defines any service running within the app
-type Service interface {
-	// Stop is to shut down the running service
+// Component defines any component running within the app
+type Component interface {
+	// Stop is to shut down the running component
 	Stop() error
 }