Fix unchecked cast panic in traffic-manager pod watcher.

A watcher isn't guaranteed to always receive an object of the watched
type. The `DeleteFunc` in particular, can receive an instance of
`cache.DeleteFinalStateUnknown`. This commit ensures that the traffic-
manager's node and pod watcher uses checked casts only and that the
`cache.DeleteFinalStateUnknown` is handled properly.

Closed #3149

Signed-off-by: Thomas Hallgren <[email protected]>

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Changelog
 
+### 2.13.2 (TBD)
+
+- Bugfix: The traffic-manager would sometimes panic and exit after some time due to a type cast panic.
+
+### 2.13.1 (April 20, 2023)
+
+- Change: Update ambassador-agent to version 1.13.13
+
 ### 2.13.0 (April 18, 2023)
 
 - Feature: The Docker network used by a Kind or Minikube (using the "docker" driver) installation, is automatically

cmd/traffic/cmd/manager/internal/cluster/nodewatcher.go

@@ -32,13 +32,25 @@ func newNodeWatcher(ctx context.Context, lister licorev1.NodeLister, informer ca
 	}
 	_, err := informer.AddEventHandler(cache.ResourceEventHandlerFuncs{
 		AddFunc: func(obj any) {
-			w.onNodeAdded(ctx, obj.(*corev1.Node))
+			if node, ok := obj.(*corev1.Node); ok {
+				w.onNodeAdded(ctx, node)
+			}
 		},
 		DeleteFunc: func(obj any) {
-			w.onNodeDeleted(ctx, obj.(*corev1.Node))
+			if node, ok := obj.(*corev1.Node); ok {
+				w.onNodeDeleted(ctx, node)
+			} else if dfsu, ok := obj.(*cache.DeletedFinalStateUnknown); ok {
+				if node, ok := dfsu.Obj.(*corev1.Node); ok {
+					w.onNodeDeleted(ctx, node)
+				}
+			}
 		},
 		UpdateFunc: func(oldObj, newObj any) {
-			w.onNodeUpdated(ctx, oldObj.(*corev1.Node), newObj.(*corev1.Node))
+			if oldNode, ok := oldObj.(*corev1.Node); ok {
+				if newNode, ok := newObj.(*corev1.Node); ok {
+					w.onNodeUpdated(ctx, oldNode, newNode)
+				}
+			}
 		},
 	})
 	if err != nil {

cmd/traffic/cmd/manager/internal/cluster/podwatcher.go

@@ -41,13 +41,25 @@ func newPodWatcher(ctx context.Context, listers []PodLister, informers []cache.S
 	for _, informer := range informers {
 		_, err := informer.AddEventHandler(cache.ResourceEventHandlerFuncs{
 			AddFunc: func(obj any) {
-				w.onPodAdded(ctx, obj.(*corev1.Pod))
+				if pod, ok := obj.(*corev1.Pod); ok {
+					w.onPodAdded(ctx, pod)
+				}
 			},
 			DeleteFunc: func(obj any) {
-				w.onPodDeleted(ctx, obj.(*corev1.Pod))
+				if pod, ok := obj.(*corev1.Pod); ok {
+					w.onPodDeleted(ctx, pod)
+				} else if dfsu, ok := obj.(*cache.DeletedFinalStateUnknown); ok {
+					if pod, ok := dfsu.Obj.(*corev1.Pod); ok {
+						w.onPodDeleted(ctx, pod)
+					}
+				}
 			},
 			UpdateFunc: func(oldObj, newObj any) {
-				w.onPodUpdated(ctx, oldObj.(*corev1.Pod), newObj.(*corev1.Pod))
+				if oldPod, ok := oldObj.(*corev1.Pod); ok {
+					if newPod, ok := newObj.(*corev1.Pod); ok {
+						w.onPodUpdated(ctx, oldPod, newPod)
+					}
+				}
 			},
 		})
 		if err != nil {