Initial commit

vendor/sigs.k8s.io/controller-runtime/pkg/webhook/admission/http.go

@@ -0,0 +1,115 @@
+/*
+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 admission
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"time"
+
+	"k8s.io/api/admission/v1beta1"
+	admissionv1beta1 "k8s.io/api/admission/v1beta1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/serializer"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	"sigs.k8s.io/controller-runtime/pkg/webhook/admission/types"
+	"sigs.k8s.io/controller-runtime/pkg/webhook/internal/metrics"
+)
+
+var admissionv1beta1scheme = runtime.NewScheme()
+var admissionv1beta1schemecodecs = serializer.NewCodecFactory(admissionv1beta1scheme)
+
+func init() {
+	addToScheme(admissionv1beta1scheme)
+}
+
+func addToScheme(scheme *runtime.Scheme) {
+	utilruntime.Must(admissionv1beta1.AddToScheme(scheme))
+}
+
+var _ http.Handler = &Webhook{}
+
+func (wh *Webhook) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	startTS := time.Now()
+	defer metrics.RequestLatency.WithLabelValues(wh.Name).Observe(time.Now().Sub(startTS).Seconds())
+
+	var body []byte
+	var err error
+
+	var reviewResponse types.Response
+	if r.Body != nil {
+		if body, err = ioutil.ReadAll(r.Body); err != nil {
+			log.Error(err, "unable to read the body from the incoming request")
+			reviewResponse = ErrorResponse(http.StatusBadRequest, err)
+			wh.writeResponse(w, reviewResponse)
+			return
+		}
+	} else {
+		err = errors.New("request body is empty")
+		log.Error(err, "bad request")
+		reviewResponse = ErrorResponse(http.StatusBadRequest, err)
+		wh.writeResponse(w, reviewResponse)
+		return
+	}
+
+	// verify the content type is accurate
+	contentType := r.Header.Get("Content-Type")
+	if contentType != "application/json" {
+		err = fmt.Errorf("contentType=%s, expect application/json", contentType)
+		log.Error(err, "unable to process a request with an unknown content type", "content type", contentType)
+		reviewResponse = ErrorResponse(http.StatusBadRequest, err)
+		wh.writeResponse(w, reviewResponse)
+		return
+	}
+
+	ar := v1beta1.AdmissionReview{}
+	if _, _, err := admissionv1beta1schemecodecs.UniversalDeserializer().Decode(body, nil, &ar); err != nil {
+		log.Error(err, "unable to decode the request")
+		reviewResponse = ErrorResponse(http.StatusBadRequest, err)
+		wh.writeResponse(w, reviewResponse)
+		return
+	}
+
+	// TODO: add panic-recovery for Handle
+	reviewResponse = wh.Handle(context.Background(), types.Request{AdmissionRequest: ar.Request})
+	wh.writeResponse(w, reviewResponse)
+}
+
+func (wh *Webhook) writeResponse(w io.Writer, response types.Response) {
+	if response.Response.Result.Code != 0 {
+		if response.Response.Result.Code == http.StatusOK {
+			metrics.TotalRequests.WithLabelValues(wh.Name, "true").Inc()
+		} else {
+			metrics.TotalRequests.WithLabelValues(wh.Name, "false").Inc()
+		}
+	}
+
+	encoder := json.NewEncoder(w)
+	responseAdmissionReview := v1beta1.AdmissionReview{
+		Response: response.Response,
+	}
+	err := encoder.Encode(responseAdmissionReview)
+	if err != nil {
+		log.Error(err, "unable to encode the response")
+		wh.writeResponse(w, ErrorResponse(http.StatusInternalServerError, err))
+	}
+}