Reuse common labels

Author: ilya-hontarau

internal/controller/etcdcluster_controller.go

@@ -168,24 +168,16 @@ func (r *EtcdClusterReconciler) ensureClusterService(ctx context.Context, cluste
 		ObjectMeta: metav1.ObjectMeta{
 			Name:      cluster.Name,
 			Namespace: cluster.Namespace,
-			Labels: map[string]string{
-				"app.kubernetes.io/name":       "etcd",
-				"app.kubernetes.io/instance":   cluster.Name,
-				"app.kubernetes.io/managed-by": "etcd-operator",
-			},
+			Labels:    factory.NewLabelsBuilder().WithName().WithInstance(cluster.Name).WithManagedBy(),
 		},
 		Spec: corev1.ServiceSpec{
 			Ports: []corev1.ServicePort{
 				{Name: "peer", TargetPort: intstr.FromInt32(2380), Port: 2380, Protocol: corev1.ProtocolTCP},
 				{Name: "client", TargetPort: intstr.FromInt32(2379), Port: 2379, Protocol: corev1.ProtocolTCP},
 			},
-			Type:      corev1.ServiceTypeClusterIP,
-			ClusterIP: "None",
-			Selector: map[string]string{
-				"app.kubernetes.io/name":       "etcd",
-				"app.kubernetes.io/instance":   cluster.Name,
-				"app.kubernetes.io/managed-by": "etcd-operator",
-			},
+			Type:                     corev1.ServiceTypeClusterIP,
+			ClusterIP:                "None",
+			Selector:                 factory.NewLabelsBuilder().WithName().WithInstance(cluster.Name).WithManagedBy(),
 			PublishNotReadyAddresses: true,
 		},
 	}
@@ -216,22 +208,14 @@ func (r *EtcdClusterReconciler) ensureClusterClientService(ctx context.Context,
 		ObjectMeta: metav1.ObjectMeta{
 			Name:      r.getClientServiceName(cluster),
 			Namespace: cluster.Namespace,
-			Labels: map[string]string{
-				"app.kubernetes.io/name":       "etcd",
-				"app.kubernetes.io/instance":   cluster.Name,
-				"app.kubernetes.io/managed-by": "etcd-operator",
-			},
+			Labels:    factory.NewLabelsBuilder().WithName().WithInstance(cluster.Name).WithManagedBy(),
 		},
 		Spec: corev1.ServiceSpec{
 			Ports: []corev1.ServicePort{
 				{Name: "client", TargetPort: intstr.FromInt32(2379), Port: 2379, Protocol: corev1.ProtocolTCP},
 			},
-			Type: corev1.ServiceTypeClusterIP,
-			Selector: map[string]string{
-				"app.kubernetes.io/name":       "etcd",
-				"app.kubernetes.io/instance":   cluster.Name,
-				"app.kubernetes.io/managed-by": "etcd-operator",
-			},
+			Type:     corev1.ServiceTypeClusterIP,
+			Selector: factory.NewLabelsBuilder().WithName().WithInstance(cluster.Name).WithManagedBy(),
 		},
 	}
 	if err = ctrl.SetControllerReference(cluster, svc, r.Scheme); err != nil {

internal/controller/factory/labels_builder.go

@@ -0,0 +1,22 @@
+package factory
+
+type LabelsBuilder map[string]string
+
+func NewLabelsBuilder() LabelsBuilder {
+	return make(map[string]string)
+}
+
+func (b LabelsBuilder) WithName() LabelsBuilder {
+	b["app.kubernetes.io/name"] = "etcd"
+	return b
+}
+
+func (b LabelsBuilder) WithInstance(name string) LabelsBuilder {
+	b["app.kubernetes.io/instance"] = name
+	return b
+}
+
+func (b LabelsBuilder) WithManagedBy() LabelsBuilder {
+	b["app.kubernetes.io/managed-by"] = "etcd-operator"
+	return b
+}

internal/controller/factory/statefulset.go

@@ -38,11 +38,7 @@ func CreateOrUpdateStatefulSet(
 	rscheme *runtime.Scheme,
 ) error {
 	podMetadata := metav1.ObjectMeta{
-		Labels: map[string]string{
-			"app.kubernetes.io/name":       "etcd",
-			"app.kubernetes.io/instance":   cluster.Name,
-			"app.kubernetes.io/managed-by": "etcd-operator",
-		},
+		Labels: NewLabelsBuilder().WithName().WithInstance(cluster.Name).WithManagedBy(),
 	}
 
 	if cluster.Spec.PodSpec.PodMetadata != nil {
@@ -88,11 +84,7 @@ func CreateOrUpdateStatefulSet(
 			ServiceName:         cluster.Name,
 			PodManagementPolicy: appsv1.ParallelPodManagement,
 			Selector: &metav1.LabelSelector{
-				MatchLabels: map[string]string{
-					"app.kubernetes.io/name":       "etcd",
-					"app.kubernetes.io/instance":   cluster.Name,
-					"app.kubernetes.io/managed-by": "etcd-operator",
-				},
+				MatchLabels: NewLabelsBuilder().WithName().WithInstance(cluster.Name).WithManagedBy(),
 			},
 			Template: corev1.PodTemplateSpec{
 				ObjectMeta: podMetadata,