fix(tracing): Resync informer cache in root owner retries

Companion to #14682 The previous retry logic relied on direct metadata API calls in cases where the informer cache hadn't updated when injecting a pod. This updates the retry logic to force a refresh of the informer cache instead of going to the metadata API. Signed-off-by: Scott Fleener <scott@buoyant.io>

Author: sfleen

controller/k8s/metadata_api.go

@@ -279,15 +279,7 @@ func (api *MetadataAPI) GetOwnerKindAndName(ctx context.Context, pod *corev1.Pod
 // Currently, this is limited to Jobs (parented by CronJobs) and ReplicaSets (parented by
 // Deployments, StatefulSets, argo Rollouts, etc.). This list may change in the future, but
 // is sufficient for now.
-var indexedParents = map[string]indexedParent{
-"Job": {Job, batchv1.SchemeGroupVersion.WithResource("jobs")},
-"ReplicaSet": {RS, appsv1.SchemeGroupVersion.WithResource("replicasets")},
-}
-
-type indexedParent struct {
-resource APIResource
-gvr schema.GroupVersionResource
-}
+var indexedParents = map[string]APIResource{"Job": Job, "ReplicaSet": RS}
 
 // GetRootOwnerKindAndName returns the resource's owner's type and metadata, using owner
 // references from the Kubernetes API. Parent refs are recursively traversed to find the
@@ -310,10 +302,10 @@ func (api *MetadataAPI) GetRootOwnerKindAndName(ctx context.Context, tm *metav1.
 log.Warnf("parent ref has no kind: %v", parentRef)
 return tm, om
 }
-indexedResource, ok := indexedParents[parentRef.Kind]
+resource, ok := indexedParents[parentRef.Kind]
 if ok {
 getFromInformer := func() (*metav1.TypeMeta, *metav1.ObjectMeta, error) {
-parent, err := api.getByNamespace(indexedResource.resource, om.Namespace, parentRef.Name)
+parent, err := api.getByNamespace(resource, om.Namespace, parentRef.Name)
 if err != nil {
 return nil, nil, err
 }
@@ -328,20 +320,19 @@ func (api *MetadataAPI) GetRootOwnerKindAndName(ctx context.Context, tm *metav1.
 if err == nil {
 return parentTm, parentOm
 }
-log.Warnf("failed to retrieve %s from informer %s/%s: %s", parentRef.Kind, om.Namespace, parentRef.Name, err)
 if retry {
-parentFromApi, err := api.client.
-Resource(indexedResource.gvr).
-Namespace(om.Namespace).
-Get(ctx, parentRef.Name, metav1.GetOptions{})
+log.Warnf("failed to retrieve %s from informer %s/%s, resyncing informer cache", parentRef.Kind, om.Namespace, parentRef.Name)
+// The proxy injnector runs very soon after a resource is created,
+// which leaves a small possibility that the informer cache hasn't
+// picked up the new resource yet. If that is the case, we force an
+// informer resync to pick up the new resource.
+api.Sync(nil)
+parentTm, parentOm, err := getFromInformer()
 if err == nil {
-if parentFromApi.ObjectMeta.Namespace == "" {
-parentFromApi.ObjectMeta.Namespace = om.Namespace
-}
-return api.GetRootOwnerKindAndName(ctx, &parentFromApi.TypeMeta, &parentFromApi.ObjectMeta, retry)
+return parentTm, parentOm
 }
-log.Warnf("failed to retrieve %s from direct API call %s/%s: %s", parentRef.Kind, om.Namespace, parentRef.Name, err)
 }
+log.Warnf("failed to retrieve %s from informer %s/%s: %s", parentRef.Kind, om.Namespace, parentRef.Name, err)
 return &parentType, &metav1.ObjectMeta{Name: parentRef.Name, Namespace: om.Namespace}
 }