Emit event when skipping mirroring of a service (linkerd#7655)

Follow up to linkerd#7597

Emit an event when service mirroring is skipped due to the namespace not existing in the source cluster.

Signed-off-by: Alex Leong <[email protected]>

Author: adleong

multicluster/service-mirror/cluster_watcher.go

@@ -474,6 +474,7 @@ func (rcsw *RemoteClusterServiceWatcher) handleRemoteServiceCreated(ctx context.
 	// Ensure the namespace exists, and skip mirroring if it doesn't
 	if _, err := rcsw.localAPIClient.Client.CoreV1().Namespaces().Get(ctx, remoteService.Namespace, metav1.GetOptions{}); err != nil {
 		if kerrors.IsNotFound(err) {
+			rcsw.recorder.Event(remoteService, v1.EventTypeNormal, eventTypeSkipped, "Skipped mirroring service: namespace does not exist")
 			rcsw.log.Warnf("Skipping mirroring of service %s: namespace %s does not exist", serviceInfo, remoteService.Namespace)
 			return nil
 		}

multicluster/service-mirror/cluster_watcher_mirroring_test.go

@@ -11,8 +11,10 @@ import (
 	"github.com/linkerd/linkerd2/pkg/multicluster"
 	logging "github.com/sirupsen/logrus"
 	corev1 "k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/tools/record"
 	"k8s.io/client-go/util/workqueue"
 )
 
@@ -221,6 +223,7 @@ func TestLocalNamespaceCreatedAfterServiceExport(t *testing.T) {
 	localAPI.Sync(nil)
 
 	q := workqueue.NewRateLimitingQueue(workqueue.DefaultControllerRateLimiter())
+	eventRecorder := record.NewFakeRecorder(100)
 
 	watcher := RemoteClusterServiceWatcher{
 		link: &multicluster.Link{
@@ -235,6 +238,7 @@ func TestLocalNamespaceCreatedAfterServiceExport(t *testing.T) {
 		remoteAPIClient:         remoteAPI,
 		localAPIClient:          localAPI,
 		stopper:                 nil,
+		recorder:                eventRecorder,
 		log:                     logging.WithFields(logging.Fields{"cluster": clusterName}),
 		eventsQueue:             q,
 		requeueLimit:            0,
@@ -268,6 +272,11 @@ func TestLocalNamespaceCreatedAfterServiceExport(t *testing.T) {
 		t.Fatalf("unexpected error: %v", err)
 	}
 
+	skippedEvent := <-eventRecorder.Events
+	if skippedEvent != fmt.Sprintf("%s %s %s", v1.EventTypeNormal, eventTypeSkipped, "Skipped mirroring service: namespace does not exist") {
+		t.Error("Expected skipped event, got:", skippedEvent)
+	}
+
 	ns, err := localAPI.Client.CoreV1().Namespaces().Create(context.Background(), &corev1.Namespace{ObjectMeta: metav1.ObjectMeta{Name: "ns1"}}, metav1.CreateOptions{})
 	if err != nil {
 		t.Fatal(err)
@@ -277,9 +286,8 @@ func TestLocalNamespaceCreatedAfterServiceExport(t *testing.T) {
 	for q.Len() > 0 {
 		watcher.processNextEvent(context.Background())
 	}
-	localAPI.Sync(nil)
 
-	_, err = localAPI.Svc().Lister().Services("ns1").Get("service-one-remote")
+	_, err = localAPI.Client.CoreV1().Services("ns1").Get(context.Background(), "service-one-remote", metav1.GetOptions{})
 	if err != nil {
 		t.Fatalf("error getting service-one locally: %v", err)
 	}