From 4af39e6fdee354633966d5c1c0dc9a948d1cd35f Mon Sep 17 00:00:00 2001
From: Vince Prignano <vincepri@vmware.com>
Date: Mon, 4 Oct 2021 11:32:22 -0700
Subject: [PATCH] :seedling: Source should retry to get informers until timeout
 expires

Signed-off-by: Vince Prignano <vincepri@vmware.com>
---
 pkg/source/source.go      | 33 ++++++++++++++++++++++++++-------
 pkg/source/source_test.go |  6 +++++-
 2 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/pkg/source/source.go b/pkg/source/source.go
index a63b37c443..708c5a5bfc 100644
--- a/pkg/source/source.go
+++ b/pkg/source/source.go
@@ -21,8 +21,10 @@ import (
 	"errors"
 	"fmt"
 	"sync"
+	"time"
 
 	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/client-go/util/workqueue"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/event"
@@ -119,17 +121,34 @@ func (ks *Kind) Start(ctx context.Context, handler handler.EventHandler, queue w
 	ctx, ks.startCancel = context.WithCancel(ctx)
 	ks.started = make(chan error)
 	go func() {
-		// Lookup the Informer from the Cache and add an EventHandler which populates the Queue
-		i, err := ks.cache.GetInformer(ctx, ks.Type)
-		if err != nil {
-			kindMatchErr := &meta.NoKindMatchError{}
-			if errors.As(err, &kindMatchErr) {
-				log.Error(err, "if kind is a CRD, it should be installed before calling Start",
-					"kind", kindMatchErr.GroupKind)
+		var (
+			i       cache.Informer
+			lastErr error
+		)
+
+		// Tries to get an informer until it returns true,
+		// an error or the specified context is cancelled or expired.
+		if err := wait.PollImmediateUntilWithContext(ctx, 10*time.Second, func(ctx context.Context) (bool, error) {
+			// Lookup the Informer from the Cache and add an EventHandler which populates the Queue
+			i, lastErr = ks.cache.GetInformer(ctx, ks.Type)
+			if lastErr != nil {
+				kindMatchErr := &meta.NoKindMatchError{}
+				if errors.As(lastErr, &kindMatchErr) {
+					log.Error(lastErr, "if kind is a CRD, it should be installed before calling Start",
+						"kind", kindMatchErr.GroupKind)
+				}
+				return false, nil // Retry.
+			}
+			return true, nil
+		}); err != nil {
+			if lastErr != nil {
+				ks.started <- fmt.Errorf("failed to get informer from cache: %w", lastErr)
+				return
 			}
 			ks.started <- err
 			return
 		}
+
 		i.AddEventHandler(internal.EventHandler{Queue: queue, EventHandler: handler, Predicates: prct})
 		if !ks.cache.WaitForCacheSync(ctx) {
 			// Would be great to return something more informative here
diff --git a/pkg/source/source_test.go b/pkg/source/source_test.go
index 966e1bb95f..70c708df08 100644
--- a/pkg/source/source_test.go
+++ b/pkg/source/source_test.go
@@ -19,6 +19,7 @@ package source_test
 import (
 	"context"
 	"fmt"
+	"time"
 
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
@@ -218,13 +219,16 @@ var _ = Describe("Source", func() {
 				ic.Error = fmt.Errorf("test error")
 				q := workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "test")
 
+				ctx, cancel := context.WithTimeout(ctx, 2*time.Second)
+				defer cancel()
+
 				instance := &source.Kind{
 					Type: &corev1.Pod{},
 				}
 				Expect(instance.InjectCache(ic)).To(Succeed())
 				err := instance.Start(ctx, handler.Funcs{}, q)
 				Expect(err).NotTo(HaveOccurred())
-				Expect(instance.WaitForSync(context.Background())).To(HaveOccurred())
+				Eventually(instance.WaitForSync(context.Background())).Should(HaveOccurred())
 			})
 		})
 	})