Allow an empty service

pkg/api/types.go

@@ -593,8 +593,10 @@ type ServiceSpec struct {
 	// Optional: Supports "TCP" and "UDP".  Defaults to "TCP".
 	Protocol Protocol `json:"protocol,omitempty"`
 
-	// This service will route traffic to pods having labels matching this selector.
-	Selector map[string]string `json:"selector,omitempty"`
+	// This service will route traffic to pods having labels matching this selector. If empty or not present,
+	// the service is assumed to have endpoints set by an external process and Kubernetes will not modify
+	// those endpoints.
+	Selector map[string]string `json:"selector"`
 
 	// PortalIP is usually assigned by the master.  If specified by the user
 	// we will try to respect it or else fail the request.  This field can

pkg/api/v1beta1/conversion_test.go

@@ -192,3 +192,35 @@ func TestMinionListConversionToOld(t *testing.T) {
 		t.Errorf("Expected: %#v, got %#v", e, a)
 	}
 }
+
+func TestServiceEmptySelector(t *testing.T) {
+	// Nil map should be preserved
+	svc := &v1beta1.Service{Selector: nil}
+	data, err := newer.Scheme.EncodeToVersion(svc, "v1beta1")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	obj, err := newer.Scheme.Decode(data)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	selector := obj.(*newer.Service).Spec.Selector
+	if selector != nil {
+		t.Errorf("unexpected selector: %#v", obj)
+	}
+
+	// Empty map should be preserved
+	svc2 := &v1beta1.Service{Selector: map[string]string{}}
+	data, err = newer.Scheme.EncodeToVersion(svc2, "v1beta1")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	obj, err = newer.Scheme.Decode(data)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	selector = obj.(*newer.Service).Spec.Selector
+	if selector == nil || len(selector) != 0 {
+		t.Errorf("unexpected selector: %#v", obj)
+	}
+}

pkg/api/v1beta1/types.go

@@ -465,9 +465,11 @@ type Service struct {
 	// This service's labels.
 	Labels map[string]string `json:"labels,omitempty" description:"map of string keys and values that can be used to organize and categorize services"`
 
-	// This service will route traffic to pods having labels matching this selector.
-	Selector                   map[string]string `json:"selector,omitempty" description:"label keys and values that must match in order to receive traffic for this service"`
-	CreateExternalLoadBalancer bool              `json:"createExternalLoadBalancer,omitempty" description:"set up a cloud-provider-specific load balancer on an external IP"`
+	// This service will route traffic to pods having labels matching this selector. If null, no endpoints will be automatically created. If empty, all pods will be selected.
+	Selector map[string]string `json:"selector" description:"label keys and values that must match in order to receive traffic for this service; if empty, all pods are selected, if not specified, endpoints must be manually specified"`
+	// An external load balancer should be set up via the cloud-provider
+	CreateExternalLoadBalancer bool `json:"createExternalLoadBalancer,omitempty" description:"set up a cloud-provider-specific load balancer on an external IP"`
+
 	// PublicIPs are used by external load balancers.
 	PublicIPs []string `json:"publicIPs,omitempty" description:"externally visible IPs from which to select the address for the external load balancer"`
 

pkg/api/v1beta2/conversion_test.go

@@ -16,4 +16,41 @@ limitations under the License.
 
 package v1beta2_test
 
-import ()
+import (
+	"testing"
+
+	newer "github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/v1beta2"
+)
+
+func TestServiceEmptySelector(t *testing.T) {
+	// Nil map should be preserved
+	svc := &v1beta2.Service{Selector: nil}
+	data, err := newer.Scheme.EncodeToVersion(svc, "v1beta2")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	obj, err := newer.Scheme.Decode(data)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	selector := obj.(*newer.Service).Spec.Selector
+	if selector != nil {
+		t.Errorf("unexpected selector: %#v", obj)
+	}
+
+	// Empty map should be preserved
+	svc2 := &v1beta2.Service{Selector: map[string]string{}}
+	data, err = newer.Scheme.EncodeToVersion(svc2, "v1beta2")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	obj, err = newer.Scheme.Decode(data)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	selector = obj.(*newer.Service).Spec.Selector
+	if selector == nil || len(selector) != 0 {
+		t.Errorf("unexpected selector: %#v", obj)
+	}
+}

pkg/api/v1beta2/types.go

@@ -430,9 +430,11 @@ type Service struct {
 	// This service's labels.
 	Labels map[string]string `json:"labels,omitempty" description:"map of string keys and values that can be used to organize and categorize services"`
 
-	// This service will route traffic to pods having labels matching this selector.
-	Selector                   map[string]string `json:"selector,omitempty" description:"label keys and values that must match in order to receive traffic for this service"`
-	CreateExternalLoadBalancer bool              `json:"createExternalLoadBalancer,omitempty" description:"set up a cloud-provider-specific load balancer on an external IP"`
+	// This service will route traffic to pods having labels matching this selector. If null, no endpoints will be automatically created. If empty, all pods will be selected.
+	Selector map[string]string `json:"selector" description:"label keys and values that must match in order to receive traffic for this service; if empty, all pods are selected, if not specified, endpoints must be manually specified"`
+	// An external load balancer should be set up via the cloud-provider
+	CreateExternalLoadBalancer bool `json:"createExternalLoadBalancer,omitempty" description:"set up a cloud-provider-specific load balancer on an external IP"`
+
 	// PublicIPs are used by external load balancers.
 	PublicIPs []string `json:"publicIPs,omitempty" description:"externally visible IPs from which to select the address for the external load balancer"`
 

pkg/api/v1beta3/types.go

@@ -601,8 +601,8 @@ type ServiceSpec struct {
 	// Optional: Supports "TCP" and "UDP".  Defaults to "TCP".
 	Protocol Protocol `json:"protocol,omitempty"`
 
-	// This service will route traffic to pods having labels matching this selector.
-	Selector map[string]string `json:"selector,omitempty"`
+	// This service will route traffic to pods having labels matching this selector. If null, no endpoints will be automatically created. If empty, all pods will be selected.
+	Selector map[string]string `json:"selector"`
 
 	// PortalIP is usually assigned by the master.  If specified by the user
 	// we will try to respect it or else fail the request.  This field can

pkg/api/validation/validation.go

@@ -438,9 +438,12 @@ func ValidateService(service *api.Service, lister ServiceLister, ctx api.Context
 	} else if !supportedPortProtocols.Has(strings.ToUpper(string(service.Spec.Protocol))) {
 		allErrs = append(allErrs, errs.NewFieldNotSupported("spec.protocol", service.Spec.Protocol))
 	}
-	if labels.Set(service.Spec.Selector).AsSelector().Empty() {
-		allErrs = append(allErrs, errs.NewFieldRequired("spec.selector", service.Spec.Selector))
+
+	if service.Spec.Selector != nil {
+		allErrs = append(allErrs, validateLabels(service.Spec.Selector, "spec.selector")...)
 	}
+	allErrs = append(allErrs, validateLabels(service.Labels, "labels")...)
+
 	if service.Spec.CreateExternalLoadBalancer {
 		services, err := lister.ListServices(ctx)
 		if err != nil {
@@ -456,8 +459,6 @@ func ValidateService(service *api.Service, lister ServiceLister, ctx api.Context
 			}
 		}
 	}
-	allErrs = append(allErrs, validateLabels(service.Labels, "labels")...)
-	allErrs = append(allErrs, validateLabels(service.Spec.Selector, "selector")...)
 	return allErrs
 }
 

pkg/api/validation/validation_test.go

@@ -710,8 +710,8 @@ func TestValidateService(t *testing.T) {
 					Port: 8675,
 				},
 			},
-			// Should fail because the selector is missing.
-			numErrs: 1,
+			// Should be ok because the selector is missing.
+			numErrs: 0,
 		},
 		{
 			name: "valid 1",
@@ -824,12 +824,25 @@ func TestValidateService(t *testing.T) {
 						"NoUppercaseOrSpecialCharsLike=Equals": "bar",
 					},
 				},
+				Spec: api.ServiceSpec{
+					Port: 8675,
+				},
+			},
+			numErrs: 1,
+		},
+		{
+			name: "invalid selector",
+			svc: api.Service{
+				ObjectMeta: api.ObjectMeta{
+					Name:      "abc123",
+					Namespace: api.NamespaceDefault,
+				},
 				Spec: api.ServiceSpec{
 					Port:     8675,
 					Selector: map[string]string{"foo": "bar", "NoUppercaseOrSpecialCharsLike=Equals": "bar"},
 				},
 			},
-			numErrs: 2,
+			numErrs: 1,
 		},
 	}