GetPodsFor() called for an ExternalName service shouldn't return any pods (#2226)

Running `linkerd routes` for some resource was returning, besides the data for the resource, additional rows for each `ExternalName` service in the namespace.

Fixes #2216

Signed-off-by: Alejandro Pedraza <alejandro@buoyant.io>

controller/k8s/api.go

@@ -307,6 +307,9 @@ func (api *API) GetPodsFor(obj runtime.Object, includeFailed bool) ([]*apiv1.Pod
 		selector = labels.Set(typed.Spec.Selector).AsSelector()
 
 	case *apiv1.Service:
+		if typed.Spec.Type == apiv1.ServiceTypeExternalName {
+			return []*apiv1.Pod{}, nil
+		}
 		namespace = typed.Namespace
 		selector = labels.Set(typed.Spec.Selector).AsSelector()
 

controller/k8s/api_test.go

@@ -362,7 +362,7 @@ func TestGetPodsFor(t *testing.T) {
 
 		// all 3 of these are used to seed the k8s client
 		k8sResInput   string   // object used as input to GetPodFor()
-		k8sResResults []string // expected results from GetPodFor
+		k8sResResults []string // expected results from GetPodsFor
 		k8sResMisc    []string // additional k8s objects for seeding the k8s client
 	}
 
@@ -393,6 +393,57 @@ status:
   phase: Finished`,
 				},
 			},
+			// Retrieve pods associated to a ClusterIP service
+			getPodsForExpected{
+				err: nil,
+				k8sResInput: `
+apiVersion: v1
+kind: Service
+metadata:
+  name: emoji-svc
+  namespace: emojivoto
+spec:
+  type: ClusterIP
+  selector:
+    app: emoji-svc`,
+				k8sResResults: []string{`
+apiVersion: v1
+kind: Pod
+metadata:
+  name: emojivoto-meshed-finished
+  namespace: emojivoto
+  labels:
+    app: emoji-svc
+status:
+  phase: Running`,
+				},
+				k8sResMisc: []string{},
+			},
+			// ExternalName services shouldn't return any pods
+			getPodsForExpected{
+				err: nil,
+				k8sResInput: `
+apiVersion: v1
+kind: Service
+metadata:
+  name: emoji-svc
+  namespace: emojivoto
+spec:
+  type: ExternalName
+  externalName: someapi.example.com`,
+				k8sResResults: []string{},
+				k8sResMisc: []string{`
+apiVersion: v1
+kind: Pod
+metadata:
+  name: emojivoto-meshed-finished
+  namespace: emojivoto
+  labels:
+    app: emoji-svc
+status:
+  phase: Running`,
+				},
+			},
 			getPodsForExpected{
 				err: nil,
 				k8sResInput: `