scheduler: align plumbing with controller-manager and apiservers

cmd/controller-manager/app/insecure_serving.go

@@ -30,6 +30,8 @@ import (
 type InsecureServingInfo struct {
 	// Listener is the secure server network listener.
 	Listener net.Listener
+	// optional server name for log messages
+	Name string
 }
 
 // Serve starts an insecure http server with the given handler. It fails only if
@@ -41,6 +43,10 @@ func (s *InsecureServingInfo) Serve(handler http.Handler, shutdownTimeout time.D
 		MaxHeaderBytes: 1 << 20,
 	}
 
-	glog.Infof("Serving insecurely on %s", s.Listener.Addr())
+	if len(s.Name) > 0 {
+		glog.Infof("Serving %s insecurely on %s", s.Name, s.Listener.Addr())
+	} else {
+		glog.Infof("Serving insecurely on %s", s.Listener.Addr())
+	}
 	return server.RunServer(insecureServer, s.Listener, shutdownTimeout, stopCh)
 }

cmd/controller-manager/app/options/insecure_serving.go

@@ -38,6 +38,10 @@ type InsecureServingOptions struct {
 	// either Listener or BindAddress/BindPort/BindNetwork is set,
 	// if Listener is set, use it and omit BindAddress/BindPort/BindNetwork.
 	Listener net.Listener
+
+	// ListenFunc can be overridden to create a custom listener, e.g. for mocking in tests.
+	// It defaults to options.CreateListener.
+	ListenFunc func(network, addr string) (net.Listener, int, error)
 }
 
 // Validate ensures that the insecure port values within the range of the port.
@@ -81,8 +85,12 @@ func (s *InsecureServingOptions) ApplyTo(c **genericcontrollermanager.InsecureSe
 
 	if s.Listener == nil {
 		var err error
+		listen := options.CreateListener
+		if s.ListenFunc != nil {
+			listen = s.ListenFunc
+		}
 		addr := net.JoinHostPort(s.BindAddress.String(), fmt.Sprintf("%d", s.BindPort))
-		s.Listener, s.BindPort, err = options.CreateListener(s.BindNetwork, addr)
+		s.Listener, s.BindPort, err = listen(s.BindNetwork, addr)
 		if err != nil {
 			return fmt.Errorf("failed to create listener: %v", err)
 		}