Make HPA Controller use Namespacers

The HPA controller had previously used a single Client
object to act as three different Namespacers.  To improve
ease of extensibility and to make it clearer what the HPA
controller actually needs to use from the client, it should
use separate Namespacers for each of its needs (Scales, HPAs,
and Events).

cmd/kube-controller-manager/app/controllermanager.go

@@ -365,7 +365,7 @@ func (s *CMServer) Run(_ []string) error {
 				metrics.DefaultHeapsterService,
 				metrics.DefaultHeapsterPort,
 			)
-			podautoscaler.NewHorizontalController(hpaClient, metricsClient).
+			podautoscaler.NewHorizontalController(hpaClient, hpaClient, hpaClient, metricsClient).
 				Run(s.HorizontalPodAutoscalerSyncPeriod)
 		}
 

pkg/controller/podautoscaler/horizontal.go

@@ -38,7 +38,9 @@ const (
 )
 
 type HorizontalController struct {
-	client        client.Interface
+	scaleNamespacer client.ScaleNamespacer
+	hpaNamespacer   client.HorizontalPodAutoscalersNamespacer
+
 	metricsClient metrics.MetricsClient
 	eventRecorder record.EventRecorder
 }
@@ -46,15 +48,16 @@ type HorizontalController struct {
 var downscaleForbiddenWindow = 5 * time.Minute
 var upscaleForbiddenWindow = 3 * time.Minute
 
-func NewHorizontalController(client client.Interface, metricsClient metrics.MetricsClient) *HorizontalController {
+func NewHorizontalController(evtNamespacer client.EventNamespacer, scaleNamespacer client.ScaleNamespacer, hpaNamespacer client.HorizontalPodAutoscalersNamespacer, metricsClient metrics.MetricsClient) *HorizontalController {
 	broadcaster := record.NewBroadcaster()
-	broadcaster.StartRecordingToSink(client.Events(""))
+	broadcaster.StartRecordingToSink(evtNamespacer.Events(""))
 	recorder := broadcaster.NewRecorder(api.EventSource{Component: "horizontal-pod-autoscaler"})
 
 	return &HorizontalController{
-		client:        client,
-		metricsClient: metricsClient,
-		eventRecorder: recorder,
+		metricsClient:   metricsClient,
+		eventRecorder:   recorder,
+		scaleNamespacer: scaleNamespacer,
+		hpaNamespacer:   hpaNamespacer,
 	}
 }
 
@@ -93,7 +96,7 @@ func (a *HorizontalController) computeReplicasForCPUUtilization(hpa extensions.H
 func (a *HorizontalController) reconcileAutoscaler(hpa extensions.HorizontalPodAutoscaler) error {
 	reference := fmt.Sprintf("%s/%s/%s", hpa.Spec.ScaleRef.Kind, hpa.Namespace, hpa.Spec.ScaleRef.Name)
 
-	scale, err := a.client.Extensions().Scales(hpa.Namespace).Get(hpa.Spec.ScaleRef.Kind, hpa.Spec.ScaleRef.Name)
+	scale, err := a.scaleNamespacer.Scales(hpa.Namespace).Get(hpa.Spec.ScaleRef.Kind, hpa.Spec.ScaleRef.Name)
 	if err != nil {
 		a.eventRecorder.Event(&hpa, api.EventTypeWarning, "FailedGetScale", err.Error())
 		return fmt.Errorf("failed to query scale subresource for %s: %v", reference, err)
@@ -140,7 +143,7 @@ func (a *HorizontalController) reconcileAutoscaler(hpa extensions.HorizontalPodA
 
 	if rescale {
 		scale.Spec.Replicas = desiredReplicas
-		_, err = a.client.Extensions().Scales(hpa.Namespace).Update(hpa.Spec.ScaleRef.Kind, scale)
+		_, err = a.scaleNamespacer.Scales(hpa.Namespace).Update(hpa.Spec.ScaleRef.Kind, scale)
 		if err != nil {
 			a.eventRecorder.Eventf(&hpa, api.EventTypeWarning, "FailedRescale", "New size: %d; error: %v", desiredReplicas, err.Error())
 			return fmt.Errorf("failed to rescale %s: %v", reference, err)
@@ -163,7 +166,7 @@ func (a *HorizontalController) reconcileAutoscaler(hpa extensions.HorizontalPodA
 		hpa.Status.LastScaleTime = &now
 	}
 
-	_, err = a.client.Extensions().HorizontalPodAutoscalers(hpa.Namespace).UpdateStatus(&hpa)
+	_, err = a.hpaNamespacer.HorizontalPodAutoscalers(hpa.Namespace).UpdateStatus(&hpa)
 	if err != nil {
 		a.eventRecorder.Event(&hpa, api.EventTypeWarning, "FailedUpdateStatus", err.Error())
 		return fmt.Errorf("failed to update status for %s: %v", hpa.Name, err)
@@ -173,7 +176,7 @@ func (a *HorizontalController) reconcileAutoscaler(hpa extensions.HorizontalPodA
 
 func (a *HorizontalController) reconcileAutoscalers() error {
 	ns := api.NamespaceAll
-	list, err := a.client.Extensions().HorizontalPodAutoscalers(ns).List(api.ListOptions{})
+	list, err := a.hpaNamespacer.HorizontalPodAutoscalers(ns).List(api.ListOptions{})
 	if err != nil {
 		return fmt.Errorf("error listing nodes: %v", err)
 	}

pkg/controller/podautoscaler/horizontal_test.go

@@ -206,7 +206,7 @@ func (tc *testCase) verifyResults(t *testing.T) {
 func (tc *testCase) runTest(t *testing.T) {
 	testClient := tc.prepareTestClient(t)
 	metricsClient := metrics.NewHeapsterMetricsClient(testClient, metrics.DefaultHeapsterNamespace, metrics.DefaultHeapsterScheme, metrics.DefaultHeapsterService, metrics.DefaultHeapsterPort)
-	hpaController := NewHorizontalController(testClient, metricsClient)
+	hpaController := NewHorizontalController(testClient, testClient.Extensions(), testClient.Extensions(), metricsClient)
 	err := hpaController.reconcileAutoscalers()
 	assert.Equal(t, nil, err)
 	if tc.verifyEvents {