Move webhook examples to an actual Go example file

This moves the examples to an actual Go example file, so that we can be
sure that they actually compile.

Author: DirectXMan12

pkg/webhook/alias.go

@@ -17,6 +17,7 @@ limitations under the License.
 package webhook
 
 import (
+	"github.com/appscode/jsonpatch"
 	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
 )
 
@@ -47,6 +48,9 @@ type AdmissionHandler = admission.Handler
 // AdmissionDecoder knows how to decode objects from admission requests.
 type AdmissionDecoder = admission.Decoder
 
+// JSONPatchOp represents a single JSONPatch patch operation.
+type JSONPatchOp = jsonpatch.Operation
+
 var (
 	// Allowed indicates that the admission request should be allowed for the given reason.
 	Allowed = admission.Allowed

pkg/webhook/doc.go

@@ -18,39 +18,6 @@ limitations under the License.
 Package webhook provides methods to build and bootstrap a webhook server.
 
 Currently, it only supports admission webhooks. It will support CRD conversion webhooks in the near future.
-
-Build webhooks
-
-	webhook1 := &Webhook{
-		Path: "/mutating-pods",
-		Handler: mutatingHandler,
-	}
-
-	webhook2 := &Webhook{
-		Path: "/validating-pods",
-		Handler: validatingHandler,
-	}
-
-Create a webhook server.
-
-	hookServer := &Server{
-		CertDir: "/tmp/cert",
-	}
-	mgr.Add(hookServer)
-
-Register the webhooks in the server.
-
-	err = hookServer.Register(webhook1, webhook2)
-	if err != nil {
-		// handle error
-	}
-
-Start the server by starting the manager
-
-	err := mgr.Start(signals.SetupSignalHandler())
-	if err != nil {
-		// handle error
-	}
 */
 package webhook
 

pkg/webhook/example_test.go

@@ -0,0 +1,67 @@
+/*
+Copyright 2018 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 webhook_test
+
+import (
+	"context"
+
+	ctrl "sigs.k8s.io/controller-runtime"
+	. "sigs.k8s.io/controller-runtime/pkg/webhook"
+	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
+)
+
+var (
+	mgr ctrl.Manager
+)
+
+func Example() {
+	// Build webhooks
+	// These handlers could be also be implementations
+	// of the AdmissionHandler interface for more complex
+	// implementations.
+	mutatingHook := &Admission{
+		Handler: admission.HandlerFunc(func(ctx context.Context, req AdmissionRequest) AdmissionResponse {
+			return Patched("some changes",
+				JSONPatchOp{Operation: "add", Path: "/metadata/annotations/access", Value: "granted"},
+				JSONPatchOp{Operation: "add", Path: "/metadata/annotations/reason", Value: "not so secret"},
+			)
+		}),
+	}
+
+	validatingHook := &Admission{
+		Handler: admission.HandlerFunc(func(ctx context.Context, req AdmissionRequest) AdmissionResponse {
+			return Denied("none shall pass!")
+		}),
+	}
+
+	// Create a webhook server.
+	hookServer := &Server{
+		Port: 8443,
+	}
+	mgr.Add(hookServer)
+
+	// Register the webhooks in the server.
+	hookServer.Register("/mutating", mutatingHook)
+	hookServer.Register("/validating", validatingHook)
+
+	// Start the server by starting a previously-set-up manager
+	err := mgr.Start(ctrl.SetupSignalHandler())
+	if err != nil {
+		// handle error
+		panic(err)
+	}
+}