Change replicas field type to int32 and add validation

api/v1alpha1/etcdcluster_types.go

@@ -31,7 +31,8 @@ type EtcdClusterSpec struct {
 	// Replicas is the count of etcd instances in cluster.
 	// +optional
 	// +kubebuilder:default:=3
-	Replicas uint    `json:"replicas,omitempty"`
+	// +kubebuilder:validation:Minimum:=0
+	Replicas int32   `json:"replicas,omitempty"`
 	Storage  Storage `json:"storage,omitempty"`
 }
 

api/v1alpha1/etcdcluster_webhook.go

@@ -17,8 +17,11 @@ limitations under the License.
 package v1alpha1
 
 import (
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/api/resource"
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/util/validation/field"
 	ctrl "sigs.k8s.io/controller-runtime"
 	logf "sigs.k8s.io/controller-runtime/pkg/log"
 	"sigs.k8s.io/controller-runtime/pkg/webhook"
@@ -42,9 +45,6 @@ var _ webhook.Defaulter = &EtcdCluster{}
 // Default implements webhook.Defaulter so a webhook will be registered for the type
 func (r *EtcdCluster) Default() {
 	etcdclusterlog.Info("default", "name", r.Name)
-	if r.Spec.Replicas == 0 {
-		r.Spec.Replicas = 3
-	}
 	if r.Spec.Storage.Size.IsZero() {
 		r.Spec.Storage.Size = resource.MustParse("4Gi")
 	}
@@ -57,6 +57,20 @@ var _ webhook.Validator = &EtcdCluster{}
 // ValidateCreate implements webhook.Validator so a webhook will be registered for the type
 func (r *EtcdCluster) ValidateCreate() (admission.Warnings, error) {
 	etcdclusterlog.Info("validate create", "name", r.Name)
+	var allErrors field.ErrorList
+	if r.Spec.Replicas < 0 {
+		allErrors = append(allErrors, field.Invalid(
+			field.NewPath("spec", "replicas"),
+			r.Spec.Replicas,
+			"cluster replicas cannot be less than zero",
+		))
+	}
+	if len(allErrors) > 0 {
+		return nil, apierrors.NewInvalid(
+			schema.GroupKind{Group: GroupVersion.Group, Kind: "EtcdCluster"},
+			r.Name, allErrors)
+	}
+
 	return nil, nil
 }
 
@@ -68,10 +82,22 @@ func (r *EtcdCluster) ValidateUpdate(old runtime.Object) (admission.Warnings, er
 		warnings = append(warnings, "cluster resize is not currently supported")
 	}
 
-	if len(warnings) > 0 {
-		return warnings, nil
+	var allErrors field.ErrorList
+	if r.Spec.Replicas < 0 {
+		allErrors = append(allErrors, field.Invalid(
+			field.NewPath("spec", "replicas"),
+			r.Spec.Replicas,
+			"cluster replicas cannot be less than zero",
+		))
 	}
-	return nil, nil
+
+	var err *apierrors.StatusError
+	if len(allErrors) > 0 {
+		err = apierrors.NewInvalid(
+			schema.GroupKind{Group: GroupVersion.Group, Kind: "EtcdCluster"},
+			r.Name, allErrors)
+	}
+	return warnings, err
 }
 
 // ValidateDelete implements webhook.Validator so a webhook will be registered for the type

api/v1alpha1/etcdcluster_webhook_test.go

@@ -19,7 +19,9 @@ package v1alpha1
 import (
 	. "github.com/onsi/ginkgo/v2"
 	"github.com/onsi/gomega"
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/api/resource"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
 var _ = Describe("EtcdCluster Webhook", func() {
@@ -28,7 +30,7 @@ var _ = Describe("EtcdCluster Webhook", func() {
 		It("Should fill in the default value if a required field is empty", func() {
 			etcdCluster := &EtcdCluster{}
 			etcdCluster.Default()
-			gomega.Expect(etcdCluster.Spec.Replicas).To(gomega.Equal(uint(3)))
+			gomega.Expect(etcdCluster.Spec.Replicas).To(gomega.Equal(int32(0)), "User should have an opportunity to create cluster with 0 replicas")
 			gomega.Expect(etcdCluster.Spec.Storage.Size).To(gomega.Equal(resource.MustParse("4Gi")))
 		})
 
@@ -43,25 +45,42 @@ var _ = Describe("EtcdCluster Webhook", func() {
 				},
 			}
 			etcdCluster.Default()
-			gomega.Expect(etcdCluster.Spec.Replicas).To(gomega.Equal(uint(5)))
+			gomega.Expect(etcdCluster.Spec.Replicas).To(gomega.Equal(int32(5)))
 			gomega.Expect(etcdCluster.Spec.Storage.Size).To(gomega.Equal(resource.MustParse("10Gi")))
 		})
 	})
 
-	// Not yet applicable as currently all fields are optional.
+	Context("When creating EtcdCluster under Validating Webhook", func() {
+		It("Should deny if replicas is negative", func() {
+			etcdCluster := &EtcdCluster{
+				Spec: EtcdClusterSpec{
+					Replicas: -1,
+				},
+			}
+			_, err := etcdCluster.ValidateCreate()
+			var statusErr *apierrors.StatusError
+
+			if gomega.Expect(err).To(gomega.BeAssignableToTypeOf(statusErr)) {
+				statusErr = err.(*apierrors.StatusError)
+				gomega.Expect(statusErr.ErrStatus.Reason).To(gomega.Equal(metav1.StatusReasonInvalid))
+				gomega.Expect(statusErr.ErrStatus.Details.Causes).To(gomega.ContainElement(metav1.StatusCause{
+					Type:    metav1.CauseTypeFieldValueInvalid,
+					Message: "Invalid value: -1: cluster replicas cannot be less than zero",
+					Field:   "spec.replicas",
+				}))
+			}
+		})
 
-	//Context("When creating EtcdCluster under Validating Webhook", func() {
-	//	It("Should deny if a required field is empty", func() {
-	//
-	//		// TODO(user): Add your logic here
-	//
-	//	})
-	//
-	//	It("Should admit if all required fields are provided", func() {
-	//
-	//		// TODO(user): Add your logic here
-	//
-	//	})
-	//})
+		It("Should admit if all required fields are provided", func() {
+			etcdCluster := &EtcdCluster{
+				Spec: EtcdClusterSpec{
+					Replicas: 1,
+				},
+			}
+			w, err := etcdCluster.ValidateCreate()
+			gomega.Expect(err).To(gomega.Succeed())
+			gomega.Expect(w).To(gomega.BeEmpty())
+		})
+	})
 
 })

config/crd/bases/etcd.aenix.io_etcdclusters.yaml

@@ -42,6 +42,8 @@ spec:
               replicas:
                 default: 3
                 description: Replicas is the count of etcd instances in cluster.
+                format: int32
+                minimum: 0
                 type: integer
               storage:
                 properties:

internal/controller/etcdcluster_controller.go

@@ -302,7 +302,7 @@ func (r *EtcdClusterReconciler) ensureClusterStatefulSet(
 		notFound = true
 		// prepare initial cluster members
 		initialCluster := ""
-		for i := uint(0); i < cluster.Spec.Replicas; i++ {
+		for i := int32(0); i < cluster.Spec.Replicas; i++ {
 			if i > 0 {
 				initialCluster += ","
 			}
@@ -441,7 +441,7 @@ func (r *EtcdClusterReconciler) ensureClusterStatefulSet(
 				},
 			},
 		}
-		*statefulSet.Spec.Replicas = int32(cluster.Spec.Replicas)
+		*statefulSet.Spec.Replicas = cluster.Spec.Replicas
 		if err := ctrl.SetControllerReference(cluster, statefulSet, r.Scheme); err != nil {
 			return fmt.Errorf("cannot set controller reference: %w", err)
 		}

internal/controller/etcdcluster_controller_test.go

@@ -144,8 +144,8 @@ var _ = Describe("EtcdCluster Controller", func() {
 			err = k8sClient.Get(ctx, typeNamespacedName, sts)
 			Expect(err).NotTo(HaveOccurred(), "cluster statefulset should exist")
 			// mark sts as ready
-			sts.Status.ReadyReplicas = int32(etcdcluster.Spec.Replicas)
-			sts.Status.Replicas = int32(etcdcluster.Spec.Replicas)
+			sts.Status.ReadyReplicas = etcdcluster.Spec.Replicas
+			sts.Status.Replicas = etcdcluster.Spec.Replicas
 			Expect(k8sClient.Status().Update(ctx, sts)).To(Succeed())
 			// reconcile and check EtcdCluster status
 			_, err = controllerReconciler.Reconcile(ctx, reconcile.Request{