controller/podautoscaler: Improve goroutine mgmt

Make sure all threads are terminated when Run returns.

pkg/controller/podautoscaler/horizontal.go

@@ -199,20 +199,26 @@ func NewHorizontalController(
 // Run begins watching and syncing.
 func (a *HorizontalController) Run(ctx context.Context, workers int) {
 	defer utilruntime.HandleCrash()
-	defer a.queue.ShutDown()
 
 	logger := klog.FromContext(ctx)
 	logger.Info("Starting HPA controller")
-	defer logger.Info("Shutting down HPA controller")
+
+	var wg sync.WaitGroup
+	defer func() {
+		logger.Info("Shutting down HPA controller")
+		a.queue.ShutDown()
+		wg.Wait()
+	}()
 
 	if !cache.WaitForNamedCacheSyncWithContext(ctx, a.hpaListerSynced, a.podListerSynced) {
 		return
 	}
 
 	for i := 0; i < workers; i++ {
-		go wait.UntilWithContext(ctx, a.worker, time.Second)
+		wg.Go(func() {
+			wait.UntilWithContext(ctx, a.worker, time.Second)
+		})
 	}
-
 	<-ctx.Done()
 }
 

pkg/controller/podautoscaler/horizontal_test.go

@@ -825,9 +825,14 @@ func coolCPUCreationTime() metav1.Time {
 
 func (tc *testCase) runTestWithController(t *testing.T, hpaController *HorizontalController, informerFactory informers.SharedInformerFactory) {
 	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
 	informerFactory.Start(ctx.Done())
-	go hpaController.Run(ctx, 5)
+
+	var wg sync.WaitGroup
+	wg.Go(func() {
+		hpaController.Run(ctx, 5)
+	})
+	defer wg.Wait()
+	defer cancel()
 
 	tc.Lock()
 	shouldWait := tc.verifyEvents