Add webhook framework

api/v1alpha4/nestedcluster_webhook.go

@@ -0,0 +1,68 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package v1alpha4
+
+import (
+	"reflect"
+
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/util/validation/field"
+	"sigs.k8s.io/controller-runtime/pkg/builder"
+	"sigs.k8s.io/controller-runtime/pkg/manager"
+	"sigs.k8s.io/controller-runtime/pkg/webhook"
+)
+
+// NestedclusterImmutableMsg ...
+const NestedclusterImmutableMsg = "Nestedclusters spec field is immutable. Please create a new resource instead. Ref doc: https://cluster-api.sigs.k8s.io/tasks/change-machine-template.html"
+
+func (r *NestedCluster) SetupWebhookWithManager(mgr manager.Manager) error {
+	return builder.WebhookManagedBy(mgr).
+		For(r).
+		Complete()
+}
+
+// +kubebuilder:webhook:verbs=create;update,path=/validate-infrastructure-cluster-x-k8s-io-v1alpha4-nestedcluster,mutating=false,failurePolicy=fail,matchPolicy=Equivalent,groups=infrastructure.cluster.x-k8s.io,resources=nestedclusters,versions=v1alpha4,name=validation.nestedclusters.infrastructure.x-k8s.io,sideEffects=None,admissionReviewVersions=v1beta1
+
+var _ webhook.Validator = &NestedCluster{}
+
+// ValidateCreate implements webhook.Validator so a webhook will be registered for the type.
+func (r *NestedCluster) ValidateCreate() error {
+	return nil
+}
+
+// ValidateUpdate implements webhook.Validator so a webhook will be registered for the type.
+func (r *NestedCluster) ValidateUpdate(old runtime.Object) error {
+	var allErrs field.ErrorList
+	oldNestedcluster := old.(*NestedCluster)
+
+	if !reflect.DeepEqual(r.Spec, oldNestedcluster.Spec) {
+		allErrs = append(allErrs,
+			field.Invalid(field.NewPath("spec", "template", "spec"), r, NestedclusterImmutableMsg),
+		)
+	}
+
+	if len(allErrs) != 0 {
+		return aggregateObjErrors(r.GroupVersionKind().GroupKind(), r.Name, allErrs)
+	}
+
+	return nil
+}
+
+// ValidateDelete implements webhook.Validator so a webhook will be registered for the type.
+func (r *NestedCluster) ValidateDelete() error {
+	return nil
+}

api/v1alpha4/webhooks.go

@@ -0,0 +1,35 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package v1alpha4
+
+import (
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/util/validation/field"
+)
+
+func aggregateObjErrors(gk schema.GroupKind, name string, allErrs field.ErrorList) error {
+	if len(allErrs) == 0 {
+		return nil
+	}
+
+	return apierrors.NewInvalid(
+		gk,
+		name,
+		allErrs,
+	)
+}

config/default/kustomization.yaml

@@ -14,9 +14,9 @@ bases:
 - ../manager
 # [WEBHOOK] To enable webhook, uncomment all the sections with [WEBHOOK] prefix including the one in
 # crd/kustomization.yaml
-#- ../webhook
+- ../webhook
 # [CERTMANAGER] To enable cert-manager, uncomment all sections with 'CERTMANAGER'. 'WEBHOOK' components are required.
-#- ../certmanager
+- ../certmanager
 # [PROMETHEUS] To enable prometheus monitor, uncomment all sections with 'PROMETHEUS'.
 #- ../prometheus
 
@@ -30,39 +30,39 @@ patchesStrategicMerge:
 
 # [WEBHOOK] To enable webhook, uncomment all the sections with [WEBHOOK] prefix including the one in
 # crd/kustomization.yaml
-#- manager_webhook_patch.yaml
+- manager_webhook_patch.yaml
 
 # [CERTMANAGER] To enable cert-manager, uncomment all sections with 'CERTMANAGER'.
 # Uncomment 'CERTMANAGER' sections in crd/kustomization.yaml to enable the CA injection in the admission webhooks.
 # 'CERTMANAGER' needs to be enabled to use ca injection
-#- webhookcainjection_patch.yaml
+- webhookcainjection_patch.yaml
 
 # the following config is for teaching kustomize how to do var substitution
 vars:
 # [CERTMANAGER] To enable cert-manager, uncomment all sections with 'CERTMANAGER' prefix.
-#- name: CERTIFICATE_NAMESPACE # namespace of the certificate CR
-#  objref:
-#    kind: Certificate
-#    group: cert-manager.io
-#    version: v1alpha2
-#    name: serving-cert # this name should match the one in certificate.yaml
-#  fieldref:
-#    fieldpath: metadata.namespace
-#- name: CERTIFICATE_NAME
-#  objref:
-#    kind: Certificate
-#    group: cert-manager.io
-#    version: v1alpha2
-#    name: serving-cert # this name should match the one in certificate.yaml
-#- name: SERVICE_NAMESPACE # namespace of the service
-#  objref:
-#    kind: Service
-#    version: v1
-#    name: webhook-service
-#  fieldref:
-#    fieldpath: metadata.namespace
-#- name: SERVICE_NAME
-#  objref:
-#    kind: Service
-#    version: v1
-#    name: webhook-service
+- name: CERTIFICATE_NAMESPACE # namespace of the certificate CR
+  objref:
+    kind: Certificate
+    group: cert-manager.io
+    version: v1alpha2
+    name: serving-cert # this name should match the one in certificate.yaml
+  fieldref:
+    fieldpath: metadata.namespace
+- name: CERTIFICATE_NAME
+  objref:
+    kind: Certificate
+    group: cert-manager.io
+    version: v1alpha2
+    name: serving-cert # this name should match the one in certificate.yaml
+- name: SERVICE_NAMESPACE # namespace of the service
+  objref:
+    kind: Service
+    version: v1
+    name: capn-webhook-service
+  fieldref:
+    fieldpath: metadata.namespace
+- name: SERVICE_NAME
+  objref:
+    kind: Service
+    version: v1
+    name: capn-webhook-service

config/default/webhookcainjection_patch.yaml

@@ -1,13 +1,13 @@
 # This patch add annotation to admission webhook config and
 # the variables $(CERTIFICATE_NAMESPACE) and $(CERTIFICATE_NAME) will be substituted by kustomize.
-apiVersion: admissionregistration.k8s.io/v1beta1
-kind: MutatingWebhookConfiguration
-metadata:
-  name: mutating-webhook-configuration
-  annotations:
-    cert-manager.io/inject-ca-from: $(CERTIFICATE_NAMESPACE)/$(CERTIFICATE_NAME)
+#apiVersion: admissionregistration.k8s.io/v1beta1
+#kind: MutatingWebhookConfiguration
+#metadata:
+#  name: mutating-webhook-configuration
+#  annotations:
+#    cert-manager.io/inject-ca-from: $(CERTIFICATE_NAMESPACE)/$(CERTIFICATE_NAME)
 ---
-apiVersion: admissionregistration.k8s.io/v1beta1
+apiVersion: admissionregistration.k8s.io/v1
 kind: ValidatingWebhookConfiguration
 metadata:
   name: validating-webhook-configuration

config/webhook/manifests.yaml

@@ -0,0 +1,29 @@
+
+---
+apiVersion: admissionregistration.k8s.io/v1
+kind: ValidatingWebhookConfiguration
+metadata:
+  creationTimestamp: null
+  name: validating-webhook-configuration
+webhooks:
+- admissionReviewVersions:
+  - v1beta1
+  clientConfig:
+    service:
+      name: capn-capn-webhook-service
+      namespace: capn-system
+      path: /validate-infrastructure-cluster-x-k8s-io-v1alpha4-nestedcluster
+  failurePolicy: Fail
+  matchPolicy: Equivalent
+  name: validation.nestedclusters.infrastructure.x-k8s.io
+  rules:
+  - apiGroups:
+    - infrastructure.cluster.x-k8s.io
+    apiVersions:
+    - v1alpha4
+    operations:
+    - CREATE
+    - UPDATE
+    resources:
+    - nestedclusters
+  sideEffects: None

config/webhook/service.yaml

@@ -2,8 +2,8 @@
 apiVersion: v1
 kind: Service
 metadata:
-  name: webhook-service
-  namespace: system
+  name: capn-webhook-service
+  namespace: capn-system
 spec:
   ports:
     - port: 443

main.go

@@ -155,7 +155,12 @@ func main() {
 		setupLog.Error(err, "unable to create controller", "controller", "NestedCluster")
 		os.Exit(1)
 	}
+
 	// +kubebuilder:scaffold:builder
+	if err := (&infrastructurev1.NestedCluster{}).SetupWebhookWithManager(mgr); err != nil {
+		setupLog.Error(err, "unable to create webhook", "webhook", "NestedCluster")
+		os.Exit(1)
+	}
 
 	setupLog.Info("Starting manager", "version", version.Get().String())
 	if err := mgr.Start(ctx); err != nil {