Pull common webhook code into generic webhook plugin.

plugin/pkg/webhook/webhook.go

@@ -0,0 +1,68 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+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 implements a generic HTTP webhook plugin.
+package webhook
+
+import (
+	"fmt"
+
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/api/unversioned"
+	"k8s.io/kubernetes/pkg/apimachinery/registered"
+	"k8s.io/kubernetes/pkg/client/restclient"
+	"k8s.io/kubernetes/pkg/client/unversioned/clientcmd"
+	"k8s.io/kubernetes/pkg/runtime"
+	runtimeserializer "k8s.io/kubernetes/pkg/runtime/serializer"
+
+	_ "k8s.io/kubernetes/pkg/apis/authorization/install"
+)
+
+type GenericWebhook struct {
+	RestClient *restclient.RESTClient
+}
+
+// New creates a new GenericWebhook from the provided kubeconfig file.
+func NewGenericWebhook(kubeConfigFile string, groupVersions []unversioned.GroupVersion) (*GenericWebhook, error) {
+	for _, groupVersion := range groupVersions {
+		if !registered.IsEnabledVersion(groupVersion) {
+			return nil, fmt.Errorf("webhook plugin requires enabling extension resource: %s", groupVersion)
+		}
+	}
+
+	loadingRules := clientcmd.NewDefaultClientConfigLoadingRules()
+	loadingRules.ExplicitPath = kubeConfigFile
+	loader := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, &clientcmd.ConfigOverrides{})
+
+	clientConfig, err := loader.ClientConfig()
+	if err != nil {
+		return nil, err
+	}
+	codec := api.Codecs.LegacyCodec(groupVersions...)
+	clientConfig.ContentConfig.NegotiatedSerializer = runtimeserializer.NegotiatedSerializerWrapper(
+		runtime.SerializerInfo{Serializer: codec},
+		runtime.StreamSerializerInfo{},
+	)
+
+	restClient, err := restclient.UnversionedRESTClientFor(clientConfig)
+	if err != nil {
+		return nil, err
+	}
+
+	// TODO(ericchiang): Can we ensure remote service is reachable?
+
+	return &GenericWebhook{restClient}, nil
+}