Reuse common labels

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/labels_builder_test.go

@@ -0,0 +1,40 @@
+package factory
+
+import (
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("Labels builder", func() {
+	Context("When ensuring a labels builder", func() {
+		It("constructor returns empty initialized map", func() {
+			builder := NewLabelsBuilder()
+			Expect(builder).To(Equal(make(LabelsBuilder)))
+		})
+		It("WithName sets correct key and value", func() {
+			builder := NewLabelsBuilder()
+			builder.WithName()
+			Expect(builder["app.kubernetes.io/name"]).To(Equal("etcd"))
+		})
+		It("WithManagedBy sets correct key and value", func() {
+			builder := NewLabelsBuilder()
+			builder.WithManagedBy()
+			Expect(builder["app.kubernetes.io/managed-by"]).To(Equal("etcd-operator"))
+		})
+		It("WithInstance sets correct key and value", func() {
+			builder := NewLabelsBuilder()
+			builder.WithInstance("local")
+			Expect(builder["app.kubernetes.io/instance"]).To(Equal("local"))
+		})
+		It("Chaining methods builds correct map", func() {
+			builder := NewLabelsBuilder()
+			builder.WithName().WithManagedBy().WithInstance("local")
+			expected := map[string]string{
+				"app.kubernetes.io/name":       "etcd",
+				"app.kubernetes.io/instance":   "local",
+				"app.kubernetes.io/managed-by": "etcd-operator",
+			}
+			Expect(builder).To(Equal(LabelsBuilder(expected)))
+		})
+	})
+})

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,

internal/controller/factory/svc.go

@@ -44,24 +44,16 @@ func CreateOrUpdateClusterService(
 		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:    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:                 NewLabelsBuilder().WithName().WithInstance(cluster.Name).WithManagedBy(),
 			PublishNotReadyAddresses: true,
 		},
 	}
@@ -83,22 +75,14 @@ func CreateOrUpdateClientService(
 		ObjectMeta: metav1.ObjectMeta{
 			Name:      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:    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: NewLabelsBuilder().WithName().WithInstance(cluster.Name).WithManagedBy(),
 		},
 	}