Refactor how to handle sigterm and nginx process goroutine (#4959)

cmd/nginx/main.go

@@ -125,23 +125,22 @@ func main() {
 	}
 	mc.Start()
 
-	ngx := controller.NewNGINXController(conf, mc)
-	go handleSigterm(ngx, func(code int) {
-		os.Exit(code)
-	})
-
-	mux := http.NewServeMux()
-
 	if conf.EnableProfiling {
 		go registerProfiler()
 	}
 
+	ngx := controller.NewNGINXController(conf, mc)
+
+	mux := http.NewServeMux()
 	registerHealthz(nginx.HealthPath, ngx, mux)
 	registerMetrics(reg, mux)
 
 	go startHTTPServer(conf.ListenPorts.Health, mux)
+	go ngx.Start()
 
-	ngx.Start()
+	handleSigterm(ngx, func(code int) {
+		os.Exit(code)
+	})
 }
 
 type exiter func(code int)

internal/ingress/controller/nginx.go

@@ -334,7 +334,7 @@ func (n *NGINXController) Start() {
 		select {
 		case err := <-n.ngxErrCh:
 			if n.isShuttingDown {
-				break
+				return
 			}
 
 			// if the nginx master process dies the workers continue to process requests,
@@ -358,6 +358,7 @@ func (n *NGINXController) Start() {
 			if n.isShuttingDown {
 				break
 			}
+
 			if evt, ok := event.(store.Event); ok {
 				klog.V(3).Infof("Event %v received - object %v", evt.Type, evt.Obj)
 				if evt.Type == store.ConfigurationEvent {
@@ -371,7 +372,7 @@ func (n *NGINXController) Start() {
 				klog.Warningf("Unexpected event type received %T", event)
 			}
 		case <-n.stopCh:
-			break
+			return
 		}
 	}
 }