✨ Allow customizing generated webhook K8s Service

Allow customizing the webhook K8s Service's name, namespace, and port.

## example usage

Look for the new `serviceName`, `serviceNamespace`, and `servicePort` fields.

```
❯ GOBIN=(pwd)/bin go install ./cmd/*

❯ ./bin/controller-gen webhook -w

Webhook

+kubebuilder:webhook:admissionReviewVersions=<[]string>,failurePolicy=<string>,groups=<[]string>[,matchPolicy=<string>],mutating=<bool>,name=<string>[,path=<string>][,reinvocationPolicy=<string>],resources=<[]string>[,serviceName=<string>][,serviceNamespace=<string>][,servicePort=<int>][,sideEffects=<string>][,timeoutSeconds=<int>][,url=<string>],verbs=<[]string>,versions=<[]string>[,webhookVersions=<[]string>]  package  specifies how a webhook should be served.

...
```

contributes to #865

Signed-off-by: David Xia <[email protected]>

pkg/webhook/parser.go

@@ -38,8 +38,10 @@ import (
 
 // The default {Mutating,Validating}WebhookConfiguration version to generate.
 const (
-	v1                    = "v1"
-	defaultWebhookVersion = v1
+	v1                      = "v1"
+	defaultWebhookVersion   = v1
+	defaultServiceName      = "webhook-service"
+	defaultServiceNamespace = "system"
 )
 
 var (
@@ -118,6 +120,12 @@ type Config struct {
 	// Name indicates the name of this webhook configuration. Should be a domain with at least three segments separated by dots
 	Name string
 
+	// ServiceName indicates the name of the K8s Service the webhook uses.
+	ServiceName string `marker:"serviceName,optional"`
+
+	// ServiceNamespace indicates the namespace of the K8s Service the webhook uses.
+	ServiceNamespace string `marker:"serviceNamespace,optional"`
+
 	// Path specifies that path that the API server should connect to this webhook on. Must be
 	// prefixed with a '/validate-' or '/mutate-' depending on the type, and followed by
 	// $GROUP-$VERSION-$KIND where all values are lower-cased and the periods in the group
@@ -126,6 +134,9 @@ type Config struct {
 	// /validate-batch-tutorial-kubebuilder-io-v1-cronjob
 	Path string `marker:"path,optional"`
 
+	// ServicePort indicates the port of the K8s Service the webhook uses
+	ServicePort *int32 `marker:"servicePort,optional"`
+
 	// WebhookVersions specifies the target API versions of the {Mutating,Validating}WebhookConfiguration objects
 	// itself to generate. The only supported value is v1. Defaults to v1.
 	WebhookVersions []string `marker:"webhookVersions,optional"`
@@ -318,11 +329,29 @@ func (c Config) clientConfig() (admissionregv1.WebhookClientConfig, error) {
 
 	path := c.Path
 	if path != "" {
+		var name, namespace string
+		var port *int32
+
+		if c.ServiceName != "" {
+			name = c.ServiceName
+		} else {
+			name = defaultServiceName
+		}
+		if c.ServiceNamespace != "" {
+			namespace = c.ServiceNamespace
+		} else {
+			namespace = defaultServiceNamespace
+		}
+		if c.ServicePort != nil {
+			port = c.ServicePort
+		}
+
 		return admissionregv1.WebhookClientConfig{
 			Service: &admissionregv1.ServiceReference{
-				Name:      "webhook-service",
-				Namespace: "system",
+				Name:      name,
+				Namespace: namespace,
 				Path:      &path,
+				Port:      port,
 			},
 		}, nil
 	}

pkg/webhook/parser_integration_test.go

@@ -209,6 +209,52 @@ var _ = Describe("Webhook Generation From Parsing to CustomResourceDefinition",
 		assertSame(actualValidating, expectedValidating)
 	})
 
+	It("should properly generate the webhook definition when the Service is customized with the `kubebuilder:webhook` marker", func() {
+		By("switching into testdata to appease go modules")
+		cwd, err := os.Getwd()
+		Expect(err).NotTo(HaveOccurred())
+		Expect(os.Chdir("./testdata/valid-custom-service")).To(Succeed()) // go modules are directory-sensitive
+		defer func() { Expect(os.Chdir(cwd)).To(Succeed()) }()
+
+		By("loading the roots")
+		pkgs, err := loader.LoadRoots(".")
+		Expect(err).NotTo(HaveOccurred())
+		Expect(pkgs).To(HaveLen(1))
+
+		By("setting up the parser")
+		reg := &markers.Registry{}
+		Expect(reg.Register(webhook.ConfigDefinition)).To(Succeed())
+		Expect(reg.Register(webhook.WebhookConfigDefinition)).To(Succeed())
+
+		By("requesting that the manifest be generated")
+		outputDir, err := os.MkdirTemp("", "webhook-integration-test")
+		Expect(err).NotTo(HaveOccurred())
+		defer os.RemoveAll(outputDir)
+		genCtx := &genall.GenerationContext{
+			Collector:  &markers.Collector{Registry: reg},
+			Roots:      pkgs,
+			OutputRule: genall.OutputToDirectory(outputDir),
+		}
+		Expect(webhook.Generator{}.Generate(genCtx)).To(Succeed())
+		for _, r := range genCtx.Roots {
+			Expect(r.Errors).To(HaveLen(0))
+		}
+
+		By("loading the generated v1 YAML")
+		actualFile, err := os.ReadFile(path.Join(outputDir, "manifests.yaml"))
+		Expect(err).NotTo(HaveOccurred())
+		actualMutating, actualValidating := unmarshalBothV1(actualFile)
+
+		By("loading the desired v1 YAML")
+		expectedFile, err := os.ReadFile("manifests.yaml")
+		Expect(err).NotTo(HaveOccurred())
+		expectedMutating, expectedValidating := unmarshalBothV1(expectedFile)
+
+		By("comparing the two")
+		assertSame(actualMutating, expectedMutating)
+		assertSame(actualValidating, expectedValidating)
+	})
+
 	It("should generate the ordered webhook definitions", func() {
 		By("switching into testdata to appease go modules")
 		cwd, err := os.Getwd()

pkg/webhook/testdata/valid-custom-service/cronjob_types.go

@@ -0,0 +1,71 @@
+/*
+
+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.
+*/
+
+//go:generate ../../../../.run-controller-gen.sh webhook paths=. output:dir=.
+
+// +groupName=testdata.kubebuilder.io
+// +versionName=v1
+package cronjob
+
+import (
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+// EDIT THIS FILE!  THIS IS SCAFFOLDING FOR YOU TO OWN!
+// NOTE: json tags are required.  Any new fields you add must have json tags for the fields to be serialized.
+
+// CronJobSpec defines the desired state of CronJob
+type CronJobSpec struct {
+	// The schedule in Cron format, see https://en.wikipedia.org/wiki/Cron.
+	Schedule string `json:"schedule"`
+}
+
+// CronJobStatus defines the observed state of CronJob
+type CronJobStatus struct {
+	// INSERT ADDITIONAL STATUS FIELD - define observed state of cluster
+	// Important: Run "make" to regenerate code after modifying this file
+
+	// Information when was the last time the job was successfully scheduled.
+	// +optional
+	LastScheduleTime *metav1.Time `json:"lastScheduleTime,omitempty"`
+}
+
+// +kubebuilder:object:root=true
+// +kubebuilder:subresource:status
+// +kubebuilder:resource:singular=mycronjob
+
+// CronJob is the Schema for the cronjobs API
+type CronJob struct {
+	/*
+	 */
+	metav1.TypeMeta   `json:",inline"`
+	metav1.ObjectMeta `json:"metadata,omitempty"`
+
+	Spec   CronJobSpec   `json:"spec,omitempty"`
+	Status CronJobStatus `json:"status,omitempty"`
+}
+
+// +kubebuilder:object:root=true
+
+// CronJobList contains a list of CronJob
+type CronJobList struct {
+	metav1.TypeMeta `json:",inline"`
+	metav1.ListMeta `json:"metadata,omitempty"`
+	Items           []CronJob `json:"items"`
+}
+
+func init() {
+	SchemeBuilder.Register(&CronJob{}, &CronJobList{})
+}

pkg/webhook/testdata/valid-custom-service/manifests.yaml

@@ -0,0 +1,83 @@
+---
+apiVersion: admissionregistration.k8s.io/v1
+kind: MutatingWebhookConfiguration
+metadata:
+  name: mutating-webhook-configuration
+webhooks:
+- admissionReviewVersions:
+  - v1
+  - v1beta1
+  clientConfig:
+    service:
+      name: FOO
+      namespace: system
+      path: /mutate-testdata-kubebuilder-io-v1-cronjob
+  failurePolicy: Fail
+  matchPolicy: Equivalent
+  name: default.cronjob.testdata.kubebuilder.io
+  rules:
+  - apiGroups:
+    - testdata.kubebuiler.io
+    apiVersions:
+    - v1
+    operations:
+    - CREATE
+    - UPDATE
+    resources:
+    - cronjobs
+  sideEffects: None
+  timeoutSeconds: 10
+  reinvocationPolicy: IfNeeded
+---
+apiVersion: admissionregistration.k8s.io/v1
+kind: ValidatingWebhookConfiguration
+metadata:
+  name: validating-webhook-configuration
+webhooks:
+- admissionReviewVersions:
+  - v1
+  - v1beta1
+  clientConfig:
+    service:
+      name: DEAD
+      namespace: BEEF
+      path: /validate-testdata-kubebuilder-io-v1-cronjob
+      port: 1234
+  failurePolicy: Fail
+  matchPolicy: Equivalent
+  name: validation.cronjob.testdata.kubebuilder.io
+  rules:
+  - apiGroups:
+    - testdata.kubebuiler.io
+    apiVersions:
+    - v1
+    operations:
+    - CREATE
+    - UPDATE
+    resources:
+    - cronjobs
+  sideEffects: None
+  timeoutSeconds: 10
+- admissionReviewVersions:
+  - v1
+  - v1beta1
+  clientConfig:
+    service:
+      name: webhook-service
+      namespace: system
+      path: /validate-testdata-kubebuilder-io-v1-cronjob
+  failurePolicy: Fail
+  matchPolicy: Equivalent
+  name: validation.cronjob.testdata.kubebuilder.io
+  rules:
+  - apiGroups:
+    - testdata.kubebuiler.io
+    apiVersions:
+    - v1
+    operations:
+    - CREATE
+    - UPDATE
+    resources:
+    - cronjobs
+  sideEffects: NoneOnDryRun
+  timeoutSeconds: 10

pkg/webhook/testdata/valid-custom-service/webhook.go

@@ -0,0 +1,50 @@
+/*
+
+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 cronjob
+
+import (
+	"k8s.io/apimachinery/pkg/runtime"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/webhook"
+)
+
+func (c *CronJob) SetupWebhookWithManager(mgr ctrl.Manager) error {
+	return ctrl.NewWebhookManagedBy(mgr).
+		For(c).
+		Complete()
+}
+
+// +kubebuilder:webhook:webhookVersions=v1,verbs=create;update,path=/validate-testdata-kubebuilder-io-v1-cronjob,mutating=false,failurePolicy=fail,matchPolicy=Equivalent,groups=testdata.kubebuiler.io,resources=cronjobs,serviceName=DEAD,serviceNamespace=BEEF,servicePort=1234,versions=v1,name=validation.cronjob.testdata.kubebuilder.io,sideEffects=None,timeoutSeconds=10,admissionReviewVersions=v1;v1beta1
+// +kubebuilder:webhook:verbs=create;update,path=/validate-testdata-kubebuilder-io-v1-cronjob,mutating=false,failurePolicy=fail,matchPolicy=Equivalent,groups=testdata.kubebuiler.io,resources=cronjobs,versions=v1,name=validation.cronjob.testdata.kubebuilder.io,sideEffects=NoneOnDryRun,timeoutSeconds=10,admissionReviewVersions=v1;v1beta1
+// +kubebuilder:webhook:webhookVersions=v1,verbs=create;update,path=/mutate-testdata-kubebuilder-io-v1-cronjob,mutating=true,failurePolicy=fail,matchPolicy=Equivalent,groups=testdata.kubebuiler.io,resources=cronjobs,serviceName=FOO,versions=v1,name=default.cronjob.testdata.kubebuilder.io,sideEffects=None,timeoutSeconds=10,admissionReviewVersions=v1;v1beta1,reinvocationPolicy=IfNeeded
+
+var _ webhook.Defaulter = &CronJob{}
+var _ webhook.Validator = &CronJob{}
+
+func (c *CronJob) Default() {
+}
+
+func (c *CronJob) ValidateCreate() error {
+	return nil
+}
+
+func (c *CronJob) ValidateUpdate(_ runtime.Object) error {
+	return nil
+}
+
+func (c *CronJob) ValidateDelete() error {
+	return nil
+}