✨ export queue's length of Controller

pkg/controller/controller.go

@@ -79,6 +79,11 @@ type Controller interface {
 
 	// GetLogger returns this controller logger prefilled with basic information.
 	GetLogger() logr.Logger
+
+	// Len returns the current queue length, for informational purposes only. You
+	// shouldn't e.g. gate a call to Add() or Get() on Len() being a particular
+	// value, that can't be synchronized properly.
+	Len() int
 }
 
 // New returns a new Controller registered with the Manager.  The Manager will ensure that shared Caches have

pkg/internal/controller/controller.go

@@ -267,6 +267,15 @@ func (c *Controller) processNextWorkItem(ctx context.Context) bool {
 	return true
 }
 
+// Len returns the current queue length, for informational purposes only. You
+// shouldn't e.g. gate a call to Add() or Get() on Len() being a particular
+// value, that can't be synchronized properly.
+func (c *Controller) Len() int {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	return c.Queue.Len()
+}
+
 const (
 	labelError        = "error"
 	labelRequeueAfter = "requeue_after"

pkg/internal/controller/controller_test.go

@@ -467,6 +467,39 @@ var _ = Describe("controller", func() {
 			Eventually(func() int { return queue.NumRequeues(request) }).Should(Equal(0))
 		})
 
+		It("should requeue a Request if there is an error and continue processing items using Len()", func() {
+			ctx, cancel := context.WithCancel(context.Background())
+			req := reconcile.Request{
+				NamespacedName: types.NamespacedName{Namespace: "bar", Name: "foo"},
+			}
+			queue = &controllertest.Queue{
+				Interface: workqueue.New(),
+			}
+			ctrl.Queue = queue
+			defer cancel()
+			go func() {
+				defer GinkgoRecover()
+				Expect(ctrl.Start(ctx)).NotTo(HaveOccurred())
+			}()
+
+			queue.Add(request)
+			queue.Add(req)
+			Expect(ctrl.Len()).To(Equal(2))
+			By("Invoking Reconciler which will give an error")
+
+			fakeReconcile.AddResult(reconcile.Result{}, fmt.Errorf("expected error: reconcile"))
+			Expect(<-reconciled).To(Equal(req))
+
+			By("Invoking Reconciler a second time without error")
+			fakeReconcile.AddResult(reconcile.Result{}, nil)
+			Expect(ctrl.Len()).To(Equal(1))
+			Expect(<-reconciled).To(Equal(req))
+
+			By("Removing the item from the queue")
+			Expect(ctrl.Len()).To(Equal(0))
+			Eventually(func() int { return queue.NumRequeues(request) }).Should(Equal(0))
+		}, 1.0)
+
 		PIt("should forget an item if it is not a Request and continue processing items", func() {
 			// TODO(community): write this test
 		})