expose kubernetes service cluster ip (#4940)

Signed-off-by: tariqibrahim <tariq.ibrahim@microsoft.com>
Signed-off-by: tariqibrahim <tariq181290@gmail.com>

discovery/kubernetes/service.go

@@ -140,6 +140,8 @@ const (
 	serviceAnnotationPrefix  = metaLabelPrefix + "service_annotation_"
 	servicePortNameLabel     = metaLabelPrefix + "service_port_name"
 	servicePortProtocolLabel = metaLabelPrefix + "service_port_protocol"
+	serviceClusterIPLabel    = metaLabelPrefix + "service_cluster_ip"
+	serviceExternalNameLabel = metaLabelPrefix + "service_external_name"
 )
 
 func serviceLabels(svc *apiv1.Service) model.LabelSet {
@@ -169,11 +171,19 @@ func (s *Service) buildService(svc *apiv1.Service) *targetgroup.Group {
 	for _, port := range svc.Spec.Ports {
 		addr := net.JoinHostPort(svc.Name+"."+svc.Namespace+".svc", strconv.FormatInt(int64(port.Port), 10))
 
-		tg.Targets = append(tg.Targets, model.LabelSet{
+		labelSet := model.LabelSet{
 			model.AddressLabel:       lv(addr),
 			servicePortNameLabel:     lv(port.Name),
 			servicePortProtocolLabel: lv(string(port.Protocol)),
-		})
+		}
+
+		if svc.Spec.Type == apiv1.ServiceTypeExternalName {
+			labelSet[serviceExternalNameLabel] = lv(svc.Spec.ExternalName)
+		} else {
+			labelSet[serviceClusterIPLabel] = lv(svc.Spec.ClusterIP)
+		}
+
+		tg.Targets = append(tg.Targets, labelSet)
 	}
 
 	return tg

discovery/kubernetes/service_test.go

@@ -44,6 +44,8 @@ func makeMultiPortService() *v1.Service {
 					Port:     int32(30901),
 				},
 			},
+			Type:      v1.ServiceTypeClusterIP,
+			ClusterIP: "10.0.0.1",
 		},
 	}
 }
@@ -62,6 +64,8 @@ func makeSuffixedService(suffix string) *v1.Service {
 					Port:     int32(30900),
 				},
 			},
+			Type:      v1.ServiceTypeClusterIP,
+			ClusterIP: "10.0.0.1",
 		},
 	}
 }
@@ -70,6 +74,26 @@ func makeService() *v1.Service {
 	return makeSuffixedService("")
 }
 
+func makeExternalService() *v1.Service {
+	return &v1.Service{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "testservice-external",
+			Namespace: "default",
+		},
+		Spec: v1.ServiceSpec{
+			Ports: []v1.ServicePort{
+				{
+					Name:     "testport",
+					Protocol: v1.ProtocolTCP,
+					Port:     int32(31900),
+				},
+			},
+			Type:         v1.ServiceTypeExternalName,
+			ExternalName: "FooExternalName",
+		},
+	}
+}
+
 func TestServiceDiscoveryAdd(t *testing.T) {
 	n, c, w := makeDiscovery(RoleService, NamespaceDiscovery{})
 
@@ -79,14 +103,18 @@ func TestServiceDiscoveryAdd(t *testing.T) {
 			obj := makeService()
 			c.CoreV1().Services(obj.Namespace).Create(obj)
 			w.Services().Add(obj)
+			obj = makeExternalService()
+			c.CoreV1().Services(obj.Namespace).Create(obj)
+			w.Services().Add(obj)
 		},
-		expectedMaxItems: 1,
+		expectedMaxItems: 2,
 		expectedRes: map[string]*targetgroup.Group{
 			"svc/default/testservice": {
 				Targets: []model.LabelSet{
 					{
 						"__meta_kubernetes_service_port_protocol": "TCP",
 						"__address__":                          "testservice.default.svc:30900",
+						"__meta_kubernetes_service_cluster_ip": "10.0.0.1",
 						"__meta_kubernetes_service_port_name":  "testport",
 					},
 				},
@@ -96,6 +124,21 @@ func TestServiceDiscoveryAdd(t *testing.T) {
 				},
 				Source: "svc/default/testservice",
 			},
+			"svc/default/testservice-external": {
+				Targets: []model.LabelSet{
+					{
+						"__meta_kubernetes_service_port_protocol": "TCP",
+						"__address__":                             "testservice-external.default.svc:31900",
+						"__meta_kubernetes_service_port_name":     "testport",
+						"__meta_kubernetes_service_external_name": "FooExternalName",
+					},
+				},
+				Labels: model.LabelSet{
+					"__meta_kubernetes_service_name": "testservice-external",
+					"__meta_kubernetes_namespace":    "default",
+				},
+				Source: "svc/default/testservice-external",
+			},
 		},
 	}.Run(t)
 }
@@ -136,11 +179,13 @@ func TestServiceDiscoveryUpdate(t *testing.T) {
 					{
 						"__meta_kubernetes_service_port_protocol": "TCP",
 						"__address__":                          "testservice.default.svc:30900",
+						"__meta_kubernetes_service_cluster_ip": "10.0.0.1",
 						"__meta_kubernetes_service_port_name":  "testport0",
 					},
 					{
 						"__meta_kubernetes_service_port_protocol": "UDP",
 						"__address__":                          "testservice.default.svc:30901",
+						"__meta_kubernetes_service_cluster_ip": "10.0.0.1",
 						"__meta_kubernetes_service_port_name":  "testport1",
 					},
 				},
@@ -176,6 +221,7 @@ func TestServiceDiscoveryNamespaces(t *testing.T) {
 					{
 						"__meta_kubernetes_service_port_protocol": "TCP",
 						"__address__":                          "testservice.ns1.svc:30900",
+						"__meta_kubernetes_service_cluster_ip": "10.0.0.1",
 						"__meta_kubernetes_service_port_name":  "testport",
 					},
 				},
@@ -190,6 +236,7 @@ func TestServiceDiscoveryNamespaces(t *testing.T) {
 					{
 						"__meta_kubernetes_service_port_protocol": "TCP",
 						"__address__":                          "testservice.ns2.svc:30900",
+						"__meta_kubernetes_service_cluster_ip": "10.0.0.1",
 						"__meta_kubernetes_service_port_name":  "testport",
 					},
 				},

docs/configuration/configuration.md

@@ -694,9 +694,11 @@ service port.
 Available meta labels:
 
 * `__meta_kubernetes_namespace`: The namespace of the service object.
-* `__meta_kubernetes_service_name`: The name of the service object.
-* `__meta_kubernetes_service_label_<labelname>`: The label of the service object.
 * `__meta_kubernetes_service_annotation_<annotationname>`: The annotation of the service object.
+* `__meta_kubernetes_service_cluster_ip`: The cluster IP address of the service. (Does not apply to services of type ExternalName)
+* `__meta_kubernetes_service_external_name`: The DNS name of the service. (Applies to services of type ExternalName)
+* `__meta_kubernetes_service_label_<labelname>`: The label of the service object.
+* `__meta_kubernetes_service_name`: The name of the service object.
 * `__meta_kubernetes_service_port_name`: Name of the service port for the target.
 * `__meta_kubernetes_service_port_number`: Number of the service port for the target.
 * `__meta_kubernetes_service_port_protocol`: Protocol of the service port for the target.