URIResolver verifies that services actually exist (#2149)

resolver/addressable_resolver.go

@@ -158,18 +158,6 @@ func (r *URIResolver) URIFromObjectReference(ctx context.Context, ref *corev1.Ob
 		return nil, apierrs.NewNotFound(gvr.GroupResource(), ref.Name)
 	}
 
-	// K8s Services are special cased. They can be called, even though they do not satisfy the
-	// Callable interface.
-	// TODO(spencer-p,n3wscott) Verify that the service actually exists in K8s.
-	if ref.APIVersion == "v1" && ref.Kind == "Service" {
-		url := &apis.URL{
-			Scheme: "http",
-			Host:   network.GetServiceHostname(ref.Name, ref.Namespace),
-			Path:   "/",
-		}
-		return url, nil
-	}
-
 	lister, err := r.listerFactory(gvr)
 	if err != nil {
 		return nil, apierrs.NewNotFound(gvr.GroupResource(), "Lister")
@@ -180,6 +168,17 @@ func (r *URIResolver) URIFromObjectReference(ctx context.Context, ref *corev1.Ob
 		return nil, apierrs.NewNotFound(gvr.GroupResource(), ref.Name)
 	}
 
+	// K8s Services are special cased. They can be called, even though they do not satisfy the
+	// Callable interface.
+	if ref.APIVersion == "v1" && ref.Kind == "Service" {
+		url := &apis.URL{
+			Scheme: "http",
+			Host:   network.GetServiceHostname(ref.Name, ref.Namespace),
+			Path:   "/",
+		}
+		return url, nil
+	}
+
 	addressable, ok := obj.(*duckv1.AddressableType)
 	if !ok {
 		return nil, apierrs.NewBadRequest(fmt.Sprintf("%+v (%T) is not an AddressableType", ref, ref))

resolver/addressable_resolver_test.go

@@ -417,7 +417,7 @@ func TestGetURIDestinationV1(t *testing.T) {
 			wantURI: addressableDNS,
 		}, "happy ref to k8s service": {
 			objects: []runtime.Object{
-				getAddressable(),
+				getAddressableFromKRef(k8sServiceRef()),
 			},
 			dest:    duckv1.Destination{Ref: k8sServiceRef()},
 			wantURI: "http://testsink.testnamespace.svc.cluster.local/",
@@ -529,6 +529,9 @@ func TestGetURIDestinationV1(t *testing.T) {
 		}, "notFound": {
 			dest:    duckv1.Destination{Ref: unaddressableKnativeRef()},
 			wantErr: fmt.Sprintf("%s %q not found", unaddressableResource, unaddressableName),
+		}, "notFound k8s service": {
+			dest:    duckv1.Destination{Ref: k8sServiceRef()},
+			wantErr: fmt.Sprintf("services %q not found", addressableName),
 		}}
 
 	for n, tc := range tests {
@@ -771,3 +774,21 @@ func unaddressableRef() *corev1.ObjectReference {
 		Namespace:  testNS,
 	}
 }
+
+func getAddressableFromKRef(ref *duckv1.KReference) *unstructured.Unstructured {
+	return &unstructured.Unstructured{
+		Object: map[string]interface{}{
+			"apiVersion": ref.APIVersion,
+			"kind":       ref.Kind,
+			"metadata": map[string]interface{}{
+				"namespace": ref.Namespace,
+				"name":      ref.Name,
+			},
+			"status": map[string]interface{}{
+				"address": map[string]interface{}{
+					"url": addressableDNS,
+				},
+			},
+		},
+	}
+}