Don't print non-error (blank lines in this case) to stdout, and don't print blank lines for empty resources

pkg/kubectl/cmd/get/get.go

@@ -522,6 +522,9 @@ func (o *GetOptions) Run(f cmdutil.Factory, cmd *cobra.Command, args []string) e
 	// track if we write any output
 	trackingWriter := &trackingWriterWrapper{Delegate: o.Out}
 
+	// remember how much we've written
+	written := 0
+
 	w := utilprinters.GetNewTabWriter(trackingWriter)
 	for ix := range objs {
 		var mapping *meta.RESTMapping
@@ -544,11 +547,14 @@ func (o *GetOptions) Run(f cmdutil.Factory, cmd *cobra.Command, args []string) e
 			w.Flush()
 			w.SetRememberedWidths(nil)
 
-			// TODO: this doesn't belong here
 			// add linebreak between resource groups (if there is more than one)
 			// skip linebreak above first resource group
 			if lastMapping != nil && !o.NoHeaders {
-				fmt.Fprintln(o.ErrOut)
+				// If we've written output since the last time we started a new set of headers, write an empty line to separate object types
+				if written != trackingWriter.Written {
+					fmt.Fprintln(w)
+					written = trackingWriter.Written
+				}
 			}
 
 			printer, err = o.ToPrinter(mapping, nil, printWithNamespace, printWithKind)

pkg/kubectl/cmd/get/get_test.go

@@ -359,7 +359,7 @@ func TestGetMultipleResourceTypesShowKinds(t *testing.T) {
 		}),
 	}
 
-	streams, _, buf, _ := genericclioptions.NewTestIOStreams()
+	streams, _, buf, bufErr := genericclioptions.NewTestIOStreams()
 	cmd := NewCmdGet("kubectl", tf, streams)
 	cmd.SetOutput(buf)
 	cmd.Run(cmd, []string{"all"})
@@ -367,12 +367,18 @@ func TestGetMultipleResourceTypesShowKinds(t *testing.T) {
 	expected := `NAME      AGE
 pod/foo   <unknown>
 pod/bar   <unknown>
+
 NAME          AGE
 service/baz   <unknown>
 `
 	if e, a := expected, buf.String(); e != a {
 		t.Errorf("expected\n%v\ngot\n%v", e, a)
 	}
+
+	// The error out should be empty
+	if e, a := "", bufErr.String(); e != a {
+		t.Errorf("expected\n%v\ngot\n%v", e, a)
+	}
 }
 
 func TestGetMultipleTableResourceTypesShowKinds(t *testing.T) {
@@ -414,7 +420,7 @@ func TestGetMultipleTableResourceTypesShowKinds(t *testing.T) {
 		}),
 	}
 
-	streams, _, buf, _ := genericclioptions.NewTestIOStreams()
+	streams, _, buf, bufErr := genericclioptions.NewTestIOStreams()
 	cmd := NewCmdGet("kubectl", tf, streams)
 	cmd.SetOutput(buf)
 	cmd.Run(cmd, []string{"all"})
@@ -422,12 +428,71 @@ func TestGetMultipleTableResourceTypesShowKinds(t *testing.T) {
 	expected := `NAME      READY   STATUS   RESTARTS   AGE
 pod/foo   0/0              0          <unknown>
 pod/bar   0/0              0          <unknown>
+
 NAME          TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
 service/baz   ClusterIP   <none>       <none>        <none>    <unknown>
 `
 	if e, a := expected, buf.String(); e != a {
 		t.Errorf("expected\n%v\ngot\n%v", e, a)
 	}
+
+	// The error out should be empty
+	if e, a := "", bufErr.String(); e != a {
+		t.Errorf("expected\n%v\ngot\n%v", e, a)
+	}
+}
+
+func TestNoBlankLinesForGetAll(t *testing.T) {
+	tf := cmdtesting.NewTestFactory().WithNamespace("test")
+	defer tf.Cleanup()
+
+	codec := scheme.Codecs.LegacyCodec(scheme.Scheme.PrioritizedVersionsAllGroups()...)
+	tf.UnstructuredClient = &fake.RESTClient{
+		NegotiatedSerializer: resource.UnstructuredPlusDefaultContentConfig().NegotiatedSerializer,
+		Client: fake.CreateHTTPClient(func(req *http.Request) (*http.Response, error) {
+			switch p, m := req.URL.Path, req.Method; {
+			case p == "/namespaces/test/pods" && m == "GET":
+				return &http.Response{StatusCode: 200, Header: cmdtesting.DefaultHeader(), Body: emptyTableObjBody(codec)}, nil
+			case p == "/namespaces/test/replicationcontrollers" && m == "GET":
+				return &http.Response{StatusCode: 200, Header: cmdtesting.DefaultHeader(), Body: emptyTableObjBody(codec)}, nil
+			case p == "/namespaces/test/services" && m == "GET":
+				return &http.Response{StatusCode: 200, Header: cmdtesting.DefaultHeader(), Body: emptyTableObjBody(codec)}, nil
+			case p == "/namespaces/test/statefulsets" && m == "GET":
+				return &http.Response{StatusCode: 200, Header: cmdtesting.DefaultHeader(), Body: emptyTableObjBody(codec)}, nil
+			case p == "/namespaces/test/horizontalpodautoscalers" && m == "GET":
+				return &http.Response{StatusCode: 200, Header: cmdtesting.DefaultHeader(), Body: emptyTableObjBody(codec)}, nil
+			case p == "/namespaces/test/jobs" && m == "GET":
+				return &http.Response{StatusCode: 200, Header: cmdtesting.DefaultHeader(), Body: emptyTableObjBody(codec)}, nil
+			case p == "/namespaces/test/cronjobs" && m == "GET":
+				return &http.Response{StatusCode: 200, Header: cmdtesting.DefaultHeader(), Body: emptyTableObjBody(codec)}, nil
+			case p == "/namespaces/test/daemonsets" && m == "GET":
+				return &http.Response{StatusCode: 200, Header: cmdtesting.DefaultHeader(), Body: emptyTableObjBody(codec)}, nil
+			case p == "/namespaces/test/deployments" && m == "GET":
+				return &http.Response{StatusCode: 200, Header: cmdtesting.DefaultHeader(), Body: emptyTableObjBody(codec)}, nil
+			case p == "/namespaces/test/replicasets" && m == "GET":
+				return &http.Response{StatusCode: 200, Header: cmdtesting.DefaultHeader(), Body: emptyTableObjBody(codec)}, nil
+
+			default:
+				t.Fatalf("request url: %#v,and request: %#v", req.URL, req)
+				return nil, nil
+			}
+		}),
+	}
+
+	streams, _, buf, errbuf := genericclioptions.NewTestIOStreams()
+	cmd := NewCmdGet("kubectl", tf, streams)
+	cmd.SetOutput(buf)
+	cmd.Run(cmd, []string{"all"})
+
+	expected := ``
+	if e, a := expected, buf.String(); e != a {
+		t.Errorf("expected\n%v\ngot\n%v", e, a)
+	}
+	expectedErr := `No resources found in test namespace.
+`
+	if e, a := expectedErr, errbuf.String(); e != a {
+		t.Errorf("expectedErr\n%v\ngot\n%v", e, a)
+	}
 }
 
 func TestGetObjectsShowLabels(t *testing.T) {
@@ -1097,6 +1162,7 @@ func TestGetMultipleTypeObjects(t *testing.T) {
 	expected := `NAME      AGE
 pod/foo   <unknown>
 pod/bar   <unknown>
+
 NAME          AGE
 service/baz   <unknown>
 `
@@ -1135,6 +1201,7 @@ func TestGetMultipleTypeTableObjects(t *testing.T) {
 	expected := `NAME      READY   STATUS   RESTARTS   AGE
 pod/foo   0/0              0          <unknown>
 pod/bar   0/0              0          <unknown>
+
 NAME          TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
 service/baz   ClusterIP   <none>       <none>        <none>    <unknown>
 `
@@ -1279,6 +1346,7 @@ func TestGetMultipleTypeObjectsWithLabelSelector(t *testing.T) {
 	expected := `NAME      AGE
 pod/foo   <unknown>
 pod/bar   <unknown>
+
 NAME          AGE
 service/baz   <unknown>
 `
@@ -1322,6 +1390,7 @@ func TestGetMultipleTypeTableObjectsWithLabelSelector(t *testing.T) {
 	expected := `NAME      READY   STATUS   RESTARTS   AGE
 pod/foo   0/0              0          <unknown>
 pod/bar   0/0              0          <unknown>
+
 NAME          TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
 service/baz   ClusterIP   <none>       <none>        <none>    <unknown>
 `
@@ -1365,6 +1434,7 @@ func TestGetMultipleTypeObjectsWithFieldSelector(t *testing.T) {
 	expected := `NAME      AGE
 pod/foo   <unknown>
 pod/bar   <unknown>
+
 NAME          AGE
 service/baz   <unknown>
 `
@@ -1408,6 +1478,7 @@ func TestGetMultipleTypeTableObjectsWithFieldSelector(t *testing.T) {
 	expected := `NAME      READY   STATUS   RESTARTS   AGE
 pod/foo   0/0              0          <unknown>
 pod/bar   0/0              0          <unknown>
+
 NAME          TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
 service/baz   ClusterIP   <none>       <none>        <none>    <unknown>
 `
@@ -1451,6 +1522,7 @@ func TestGetMultipleTypeObjectsWithDirectReference(t *testing.T) {
 
 	expected := `NAME          AGE
 service/baz   <unknown>
+
 NAME       AGE
 node/foo   <unknown>
 `
@@ -1494,6 +1566,7 @@ func TestGetMultipleTypeTableObjectsWithDirectReference(t *testing.T) {
 
 	expected := `NAME          TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
 service/baz   ClusterIP   <none>       <none>        <none>    <unknown>
+
 NAME       STATUS    ROLES    AGE         VERSION
 node/foo   Unknown   <none>   <unknown>   
 `
@@ -2590,3 +2663,11 @@ func nodeTableObjBody(codec runtime.Codec, nodes ...corev1.Node) io.ReadCloser {
 	}
 	return cmdtesting.ObjBody(codec, table)
 }
+
+// build an empty table response
+func emptyTableObjBody(codec runtime.Codec) io.ReadCloser {
+	table := &metav1.Table{
+		ColumnDefinitions: podColumns,
+	}
+	return cmdtesting.ObjBody(codec, table)
+}

pkg/kubectl/cmd/testing/util.go

@@ -126,6 +126,30 @@ func TestData() (*corev1.PodList, *corev1.ServiceList, *corev1.ReplicationContro
 	return pods, svc, rc
 }
 
+// EmptyTestData returns no pod, service, or replication controller
+func EmptyTestData() (*corev1.PodList, *corev1.ServiceList, *corev1.ReplicationControllerList) {
+	pods := &corev1.PodList{
+		ListMeta: metav1.ListMeta{
+			ResourceVersion: "15",
+		},
+		Items: []corev1.Pod{},
+	}
+	svc := &corev1.ServiceList{
+		ListMeta: metav1.ListMeta{
+			ResourceVersion: "16",
+		},
+		Items: []corev1.Service{},
+	}
+
+	rc := &corev1.ReplicationControllerList{
+		ListMeta: metav1.ListMeta{
+			ResourceVersion: "17",
+		},
+		Items: []corev1.ReplicationController{},
+	}
+	return pods, svc, rc
+}
+
 func GenResponseWithJsonEncodedBody(bodyStruct interface{}) (*http.Response, error) {
 	jsonBytes, err := json.Marshal(bodyStruct)
 	if err != nil {