Allow no ports when exposing headless service

pkg/kubectl/cmd/expose.go

@@ -186,6 +186,8 @@ func RunExpose(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, args []str
 			params["selector"] = s
 		}
 
+		isHeadlessService := params["cluster-ip"] == "None"
+
 		// For objects that need a port, derive it from the exposed object in case a user
 		// didn't explicitly specify one via --port
 		if port, found := params["port"]; found && kubectl.IsZero(port) {
@@ -195,7 +197,9 @@ func RunExpose(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, args []str
 			}
 			switch len(ports) {
 			case 0:
+				if !isHeadlessService {
 					return cmdutil.UsageError(cmd, "couldn't find port via --port flag or introspection")
+				}
 			case 1:
 				params["port"] = ports[0]
 			default:

pkg/kubectl/cmd/expose_test.go

@@ -263,6 +263,32 @@ func TestRunExposeService(t *testing.T) {
 			status:   200,
 		},
 		{
+			name: "expose-headless-service-no-port",
+			args: []string{"service", "baz"},
+			ns:   "test",
+			calls: map[string]string{
+				"GET":  "/namespaces/test/services/baz",
+				"POST": "/namespaces/test/services",
+			},
+			input: &api.Service{
+				ObjectMeta: api.ObjectMeta{Name: "baz", Namespace: "test", ResourceVersion: "12"},
+				Spec: api.ServiceSpec{
+					Selector: map[string]string{"app": "go"},
+				},
+			},
+			flags: map[string]string{"selector": "func=stream", "name": "foo", "labels": "svc=test", "cluster-ip": "None", "dry-run": "true"},
+			output: &api.Service{
+				ObjectMeta: api.ObjectMeta{Name: "foo", Namespace: "", Labels: map[string]string{"svc": "test"}},
+				Spec: api.ServiceSpec{
+					Ports:     []api.ServicePort{},
+					Selector:  map[string]string{"func": "stream"},
+					ClusterIP: api.ClusterIPNone,
+				},
+			},
+			expected: "service \"foo\" exposed",
+			status:   200,
+		},
+		{
 			name: "expose-from-file",
 			args: []string{},
 			ns:   "test",

pkg/kubectl/service.go

@@ -110,6 +110,9 @@ func generate(genericParams map[string]interface{}) (runtime.Object, error) {
 			return nil, fmt.Errorf("'name' is a required parameter.")
 		}
 	}
+
+	isHeadlessService := params["cluster-ip"] == "None"
+
 	ports := []api.ServicePort{}
 	servicePortName, found := params["port-name"]
 	if !found {
@@ -131,11 +134,12 @@ func generate(genericParams map[string]interface{}) (runtime.Object, error) {
 	var portString string
 	if portString, found = params["ports"]; !found {
 		portString, found = params["port"]
-		if !found {
+		if !found && !isHeadlessService {
 			return nil, fmt.Errorf("'port' is a required parameter.")
 		}
 	}
 
+	if portString != "" {
 		portStringSlice := strings.Split(portString, ",")
 		for i, stillPortString := range portStringSlice {
 			port, err := strconv.Atoi(stillPortString)
@@ -170,6 +174,7 @@ func generate(genericParams map[string]interface{}) (runtime.Object, error) {
 				Protocol: api.Protocol(protocol),
 			})
 		}
+	}
 
 	service := api.Service{
 		ObjectMeta: api.ObjectMeta{

pkg/kubectl/service_test.go

@@ -536,6 +536,29 @@ func TestGenerateService(t *testing.T) {
 				},
 			},
 		},
+		{
+			generator: ServiceGeneratorV2{},
+			params: map[string]interface{}{
+				"selector":       "foo=bar,baz=blah",
+				"name":           "test",
+				"protocol":       "TCP",
+				"container-port": "1234",
+				"cluster-ip":     "None",
+			},
+			expected: api.Service{
+				ObjectMeta: api.ObjectMeta{
+					Name: "test",
+				},
+				Spec: api.ServiceSpec{
+					Selector: map[string]string{
+						"foo": "bar",
+						"baz": "blah",
+					},
+					Ports:     []api.ServicePort{},
+					ClusterIP: api.ClusterIPNone,
+				},
+			},
+		},
 	}
 	for _, test := range tests {
 		obj, err := test.generator.Generate(test.params)