supervisor gc: use singleton queue

The supervisor treats all events the same hence it must use a
singleton queue.

Updated the integration test to remove the data race caused by
calling methods on testing.T outside of the main test go routine.

Signed-off-by: Monis Khan <mok@vmware.com>

internal/controller/supervisorstorage/garbage_collector.go

@@ -59,7 +59,7 @@ func GarbageCollectorController(
 					return isSecretWithGCAnnotation(oldObj) || isSecretWithGCAnnotation(newObj)
 				},
 				DeleteFunc: func(obj metav1.Object) bool { return false }, // ignore all deletes
-				ParentFunc: nil,
+				ParentFunc: pinnipedcontroller.SingletonQueue(),
 			},
 			controllerlib.InformerOption{},
 		),
@@ -67,16 +67,20 @@ func GarbageCollectorController(
 }
 
 func (c *garbageCollectorController) Sync(ctx controllerlib.Context) error {
+	// make sure we have a consistent, static meaning for the current time during the sync loop
+	frozenClock := clock.NewFakeClock(c.clock.Now())
+
 	// The Sync method is triggered upon any change to any Secret, which would make this
 	// controller too chatty, so it rate limits itself to a more reasonable interval.
 	// Note that even during a period when no secrets are changing, it will still run
 	// at the informer's full-resync interval (as long as there are some secrets).
-	if c.clock.Now().Sub(c.timeOfMostRecentSweep) < minimumRepeatInterval {
+	if since := frozenClock.Since(c.timeOfMostRecentSweep); since < minimumRepeatInterval {
+		ctx.Queue.AddAfter(ctx.Key, minimumRepeatInterval-since)
 		return nil
 	}
 
 	plog.Info("starting storage garbage collection sweep")
-	c.timeOfMostRecentSweep = c.clock.Now()
+	c.timeOfMostRecentSweep = frozenClock.Now()
 
 	listOfSecrets, err := c.secretInformer.Lister().List(labels.Everything())
 	if err != nil {
@@ -97,7 +101,7 @@ func (c *garbageCollectorController) Sync(ctx controllerlib.Context) error {
 			continue
 		}
 
-		if garbageCollectAfterTime.Before(c.clock.Now()) {
+		if garbageCollectAfterTime.Before(frozenClock.Now()) {
 			err = c.kubeClient.CoreV1().Secrets(secret.Namespace).Delete(ctx.Context, secret.Name, metav1.DeleteOptions{})
 			if err != nil {
 				plog.WarningErr("failed to garbage collect resource", err, logKV(secret))

internal/controller/supervisorstorage/garbage_collector_test.go

@@ -66,6 +66,10 @@ func TestGarbageCollectorControllerInformerFilters(t *testing.T) {
 					r.True(subject.Update(secretWithAnnotation, otherSecret))
 					r.True(subject.Update(otherSecret, secretWithAnnotation))
 				})
+
+				it("returns the same singleton key", func() {
+					r.Equal(controllerlib.Key{}, subject.Parent(secretWithAnnotation))
+				})
 			})
 
 			when("any Secret with the required annotation is deleted", func() {
@@ -136,9 +140,10 @@ func TestGarbageCollectorControllerSync(t *testing.T) {
 				Context: cancelContext,
 				Name:    subject.Name(),
 				Key: controllerlib.Key{
-					Namespace: "",
+					Namespace: "foo",
-					Name:      "",
+					Name:      "bar",
 				},
+				Queue: &testQueue{t: t},
 			}
 
 			// Must start informers before calling TestRunSynchronously()
@@ -262,16 +267,23 @@ func TestGarbageCollectorControllerSync(t *testing.T) {
 				// Run sync once with the current time set to frozenTime.
 				r.NoError(controllerlib.TestSync(t, subject, *syncContext))
 				require.Empty(t, kubeClient.Actions())
+				r.False(syncContext.Queue.(*testQueue).called)
 
 				// Run sync again when not enough time has passed since the most recent run, so no delete
 				// operations should happen even though there is a expired secret now.
 				fakeClock.Step(29 * time.Second)
 				r.NoError(controllerlib.TestSync(t, subject, *syncContext))
 				require.Empty(t, kubeClient.Actions())
+				r.True(syncContext.Queue.(*testQueue).called)
+				r.Equal(controllerlib.Key{Namespace: "foo", Name: "bar"}, syncContext.Queue.(*testQueue).key) // assert key is passed through
+				r.Equal(time.Second, syncContext.Queue.(*testQueue).duration)                                 // assert that we get the exact requeue time
+
+				syncContext.Queue = &testQueue{t: t} // reset the queue for the next sync
 
 				// Step to the exact threshold and run Sync again. Now we are past the rate limiting period.
-				fakeClock.Step(1*time.Second + 1*time.Millisecond)
+				fakeClock.Step(time.Second)
 				r.NoError(controllerlib.TestSync(t, subject, *syncContext))
+				r.False(syncContext.Queue.(*testQueue).called)
 
 				// It should have deleted the expired secret.
 				r.ElementsMatch(
@@ -381,3 +393,23 @@ func TestGarbageCollectorControllerSync(t *testing.T) {
 		})
 	}, spec.Parallel(), spec.Report(report.Terminal{}))
 }
+
+type testQueue struct {
+	t *testing.T
+
+	called   bool
+	key      controllerlib.Key
+	duration time.Duration
+
+	controllerlib.Queue // panic if any other methods called
+}
+
+func (q *testQueue) AddAfter(key controllerlib.Key, duration time.Duration) {
+	q.t.Helper()
+
+	require.False(q.t, q.called, "AddAfter should only be called once")
+
+	q.called = true
+	q.key = key
+	q.duration = duration
+}

test/integration/supervisor_storage_garbage_collection_test.go

@@ -48,10 +48,15 @@ func TestStorageGarbageCollection(t *testing.T) {
 	// in the same namespace just to get the controller to respond faster.
 	// This is just a performance optimization to make this test pass faster because otherwise
 	// this test has to wait ~3 minutes for the controller's next full-resync.
-	stopCh := make(chan bool, 1) // It is important that this channel be buffered.
+	stopCh := make(chan struct{})
-	go updateSecretEveryTwoSeconds(t, stopCh, secrets, secretNotYetExpired)
+	errCh := make(chan error)
+	go updateSecretEveryTwoSeconds(stopCh, errCh, secrets, secretNotYetExpired)
 	t.Cleanup(func() {
-		stopCh <- true
+		close(stopCh)
+
+		if updateErr := <-errCh; updateErr != nil {
+			panic(updateErr)
+		}
 	})
 
 	// Wait long enough for the next periodic sweep of the GC controller for the secrets to be deleted, which
@@ -69,10 +74,15 @@ func TestStorageGarbageCollection(t *testing.T) {
 	require.NoError(t, err)
 }
 
-func updateSecretEveryTwoSeconds(t *testing.T, stopCh chan bool, secrets corev1client.SecretInterface, secret *v1.Secret) {
+func updateSecretEveryTwoSeconds(stopCh chan struct{}, errCh chan error, secrets corev1client.SecretInterface, secret *v1.Secret) {
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Minute)
 	defer cancel()
 
+	var updateErr error
+	defer func() {
+		errCh <- updateErr
+	}()
+
 	i := 0
 	for {
 		select {
@@ -87,9 +97,25 @@ func updateSecretEveryTwoSeconds(t *testing.T, stopCh chan bool, secrets corev1c
 
 		i++
 		secret.Data["foo"] = []byte(fmt.Sprintf("bar-%d", i))
-		var updateErr error
 		secret, updateErr = secrets.Update(ctx, secret, metav1.UpdateOptions{})
-		require.NoError(t, updateErr)
+
+		switch {
+		case updateErr == nil:
+			// continue to next update
+
+		case k8serrors.IsConflict(updateErr), k8serrors.IsNotFound(updateErr):
+			select {
+			case _, ok := <-stopCh:
+				if !ok { // stopCh is closed meaning that test is already finished so these errors are expected
+					updateErr = nil
+				}
+			default:
+			}
+
+			return // even if the error is expected, we must stop
+		default:
+			return // unexpected error
+		}
 	}
 }