Call non-blocking informerFactory.Start synchronously to avoid races

Signed-off-by: Dr. Stefan Schimanski <stefan.schimanski@gmail.com>

pkg/controller/garbagecollector/garbagecollector_test.go

@@ -223,7 +223,7 @@ func setupGC(t *testing.T, config *restclient.Config) garbageCollector {
 		t.Fatal(err)
 	}
 	stop := make(chan struct{})
-	go sharedInformers.Start(stop)
+	sharedInformers.Start(stop)
 	return garbageCollector{gc, stop}
 }
 

pkg/controller/validatingadmissionpolicystatus/controller_test.go

@@ -113,7 +113,7 @@ func TestTypeChecking(t *testing.T) {
 			if err != nil {
 				t.Fatalf("cannot create controller: %v", err)
 			}
-			go informerFactory.Start(ctx.Done())
+			informerFactory.Start(ctx.Done())
 			go controller.Run(ctx, 1)
 			err = wait.PollUntilContextCancel(ctx, time.Second, false, func(ctx context.Context) (done bool, err error) {
 				name := policy.Name

pkg/controller/volume/ephemeral/controller_test.go

@@ -152,7 +152,7 @@ func TestSyncHandler(t *testing.T) {
 			ec, _ := c.(*ephemeralController)
 
 			// Ensure informers are up-to-date.
-			go informerFactory.Start(ctx.Done())
+			informerFactory.Start(ctx.Done())
 			informerFactory.WaitForCacheSync(ctx.Done())
 			cache.WaitForCacheSync(ctx.Done(), podInformer.Informer().HasSynced, pvcInformer.Informer().HasSynced)
 

pkg/controlplane/controller/leaderelection/leaderelection_controller_test.go

@@ -32,8 +32,6 @@ import (
 	"k8s.io/client-go/informers"
 	"k8s.io/client-go/kubernetes/fake"
 	"k8s.io/utils/ptr"
-
-	"k8s.io/client-go/tools/cache"
 )
 
 func TestReconcileElectionStep(t *testing.T) {
@@ -339,7 +337,7 @@ func TestReconcileElectionStep(t *testing.T) {
 			ctx := context.Background()
 			client := fake.NewSimpleClientset()
 			informerFactory := informers.NewSharedInformerFactory(client, 0)
-			_ = informerFactory.Coordination().V1alpha1().LeaseCandidates().Lister()
+
 			controller, err := NewController(
 				informerFactory.Coordination().V1().Leases(),
 				informerFactory.Coordination().V1alpha1().LeaseCandidates(),
@@ -349,8 +347,7 @@ func TestReconcileElectionStep(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			go informerFactory.Start(ctx.Done())
+
-			informerFactory.WaitForCacheSync(ctx.Done())
 			// Set up the fake client with the existing lease
 			if tc.existingLease != nil {
 				_, err = client.CoordinationV1().Leases(tc.existingLease.Namespace).Create(ctx, tc.existingLease, metav1.CreateOptions{})
@@ -366,7 +363,10 @@ func TestReconcileElectionStep(t *testing.T) {
 					t.Fatal(err)
 				}
 			}
-			cache.WaitForCacheSync(ctx.Done(), controller.leaseCandidateInformer.Informer().HasSynced)
+
+			informerFactory.Start(ctx.Done())
+			informerFactory.WaitForCacheSync(ctx.Done())
+
 			requeue, err := controller.reconcileElectionStep(ctx, tc.leaseNN)
 
 			if (requeue != 0) != tc.expectedRequeue {
@@ -639,7 +639,7 @@ func TestController(t *testing.T) {
 				t.Fatal(err)
 			}
 
-			go informerFactory.Start(ctx.Done())
+			informerFactory.Start(ctx.Done())
 			go controller.Run(ctx, 1)
 
 			go func() {

pkg/controlplane/controller/leaderelection/leasecandidategc_controller_test.go

@@ -115,7 +115,7 @@ func TestLeaseCandidateGCController(t *testing.T) {
 			leaseCandidateInformer := informerFactory.Coordination().V1alpha1().LeaseCandidates()
 			controller := NewLeaseCandidateGC(client, 10*time.Millisecond, leaseCandidateInformer)
 
-			go informerFactory.Start(ctx.Done())
+			informerFactory.Start(ctx.Done())
 			informerFactory.WaitForCacheSync(ctx.Done())
 
 			// Create lease candidates

pkg/proxy/config/api_test.go

@@ -60,7 +60,7 @@ func TestNewServicesSourceApi_UpdatesAndMultipleServices(t *testing.T) {
 
 	serviceConfig := NewServiceConfig(ctx, sharedInformers.Core().V1().Services(), time.Minute)
 	serviceConfig.RegisterEventHandler(handler)
-	go sharedInformers.Start(stopCh)
+	sharedInformers.Start(stopCh)
 	go serviceConfig.Run(stopCh)
 
 	// Add the first service
@@ -141,7 +141,7 @@ func TestNewEndpointsSourceApi_UpdatesAndMultipleEndpoints(t *testing.T) {
 
 	endpointsliceConfig := NewEndpointSliceConfig(ctx, sharedInformers.Discovery().V1().EndpointSlices(), time.Minute)
 	endpointsliceConfig.RegisterEventHandler(handler)
-	go sharedInformers.Start(stopCh)
+	sharedInformers.Start(stopCh)
 	go endpointsliceConfig.Run(stopCh)
 
 	// Add the first endpoints

pkg/proxy/config/config_test.go

@@ -240,7 +240,7 @@ func TestNewServiceAddedAndNotified(t *testing.T) {
 	config := NewServiceConfig(ctx, sharedInformers.Core().V1().Services(), time.Minute)
 	handler := NewServiceHandlerMock()
 	config.RegisterEventHandler(handler)
-	go sharedInformers.Start(stopCh)
+	sharedInformers.Start(stopCh)
 	go config.Run(stopCh)
 
 	service := &v1.Service{
@@ -265,7 +265,7 @@ func TestServiceAddedRemovedSetAndNotified(t *testing.T) {
 	config := NewServiceConfig(ctx, sharedInformers.Core().V1().Services(), time.Minute)
 	handler := NewServiceHandlerMock()
 	config.RegisterEventHandler(handler)
-	go sharedInformers.Start(stopCh)
+	sharedInformers.Start(stopCh)
 	go config.Run(stopCh)
 
 	service1 := &v1.Service{
@@ -304,7 +304,7 @@ func TestNewServicesMultipleHandlersAddedAndNotified(t *testing.T) {
 	handler2 := NewServiceHandlerMock()
 	config.RegisterEventHandler(handler)
 	config.RegisterEventHandler(handler2)
-	go sharedInformers.Start(stopCh)
+	sharedInformers.Start(stopCh)
 	go config.Run(stopCh)
 
 	service1 := &v1.Service{
@@ -339,7 +339,7 @@ func TestNewEndpointsMultipleHandlersAddedAndNotified(t *testing.T) {
 	handler2 := NewEndpointSliceHandlerMock()
 	config.RegisterEventHandler(handler)
 	config.RegisterEventHandler(handler2)
-	go sharedInformers.Start(stopCh)
+	sharedInformers.Start(stopCh)
 	go config.Run(stopCh)
 
 	endpoints1 := &discoveryv1.EndpointSlice{
@@ -386,7 +386,7 @@ func TestNewEndpointsMultipleHandlersAddRemoveSetAndNotified(t *testing.T) {
 	handler2 := NewEndpointSliceHandlerMock()
 	config.RegisterEventHandler(handler)
 	config.RegisterEventHandler(handler2)
-	go sharedInformers.Start(stopCh)
+	sharedInformers.Start(stopCh)
 	go config.Run(stopCh)
 
 	endpoints1 := &discoveryv1.EndpointSlice{

staging/src/k8s.io/client-go/tools/leaderelection/leasecandidate.go

@@ -120,7 +120,7 @@ func NewCandidate(clientset kubernetes.Interface,
 func (c *LeaseCandidate) Run(ctx context.Context) {
 	defer c.queue.ShutDown()
 
-	go c.informerFactory.Start(ctx.Done())
+	c.informerFactory.Start(ctx.Done())
 	if !cache.WaitForNamedCacheSync("leasecandidateclient", ctx.Done(), c.hasSynced) {
 		return
 	}

staging/src/k8s.io/code-generator/cmd/informer-gen/generators/factory.go

@@ -299,6 +299,7 @@ type SharedInformerFactory interface {
 
 	// Start initializes all requested informers. They are handled in goroutines
 	// which run until the stop channel gets closed.
+	// Warning: Start does not block. When run in a go-routine, it will race with a later WaitForCacheSync.
         Start(stopCh <-chan struct{})
 
 	// Shutdown marks a factory as shutting down. At that point no new