116 lines
3.5 KiB
Go
116 lines
3.5 KiB
Go
/*
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Copyright 2018 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package admission
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import (
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"context"
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"encoding/json"
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"errors"
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"fmt"
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"io"
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"io/ioutil"
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"net/http"
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"time"
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"k8s.io/api/admission/v1beta1"
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admissionv1beta1 "k8s.io/api/admission/v1beta1"
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"k8s.io/apimachinery/pkg/runtime"
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"k8s.io/apimachinery/pkg/runtime/serializer"
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utilruntime "k8s.io/apimachinery/pkg/util/runtime"
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"sigs.k8s.io/controller-runtime/pkg/webhook/admission/types"
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"sigs.k8s.io/controller-runtime/pkg/webhook/internal/metrics"
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)
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var admissionv1beta1scheme = runtime.NewScheme()
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var admissionv1beta1schemecodecs = serializer.NewCodecFactory(admissionv1beta1scheme)
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func init() {
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addToScheme(admissionv1beta1scheme)
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}
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func addToScheme(scheme *runtime.Scheme) {
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utilruntime.Must(admissionv1beta1.AddToScheme(scheme))
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}
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var _ http.Handler = &Webhook{}
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func (wh *Webhook) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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startTS := time.Now()
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defer metrics.RequestLatency.WithLabelValues(wh.Name).Observe(time.Now().Sub(startTS).Seconds())
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var body []byte
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var err error
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var reviewResponse types.Response
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if r.Body != nil {
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if body, err = ioutil.ReadAll(r.Body); err != nil {
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log.Error(err, "unable to read the body from the incoming request")
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reviewResponse = ErrorResponse(http.StatusBadRequest, err)
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wh.writeResponse(w, reviewResponse)
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return
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}
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} else {
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err = errors.New("request body is empty")
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log.Error(err, "bad request")
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reviewResponse = ErrorResponse(http.StatusBadRequest, err)
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wh.writeResponse(w, reviewResponse)
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return
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}
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// verify the content type is accurate
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contentType := r.Header.Get("Content-Type")
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if contentType != "application/json" {
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err = fmt.Errorf("contentType=%s, expect application/json", contentType)
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log.Error(err, "unable to process a request with an unknown content type", "content type", contentType)
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reviewResponse = ErrorResponse(http.StatusBadRequest, err)
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wh.writeResponse(w, reviewResponse)
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return
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}
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ar := v1beta1.AdmissionReview{}
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if _, _, err := admissionv1beta1schemecodecs.UniversalDeserializer().Decode(body, nil, &ar); err != nil {
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log.Error(err, "unable to decode the request")
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reviewResponse = ErrorResponse(http.StatusBadRequest, err)
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wh.writeResponse(w, reviewResponse)
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return
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}
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// TODO: add panic-recovery for Handle
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reviewResponse = wh.Handle(context.Background(), types.Request{AdmissionRequest: ar.Request})
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wh.writeResponse(w, reviewResponse)
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}
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func (wh *Webhook) writeResponse(w io.Writer, response types.Response) {
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if response.Response.Result.Code != 0 {
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if response.Response.Result.Code == http.StatusOK {
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metrics.TotalRequests.WithLabelValues(wh.Name, "true").Inc()
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} else {
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metrics.TotalRequests.WithLabelValues(wh.Name, "false").Inc()
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}
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}
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encoder := json.NewEncoder(w)
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responseAdmissionReview := v1beta1.AdmissionReview{
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Response: response.Response,
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}
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err := encoder.Encode(responseAdmissionReview)
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if err != nil {
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log.Error(err, "unable to encode the response")
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wh.writeResponse(w, ErrorResponse(http.StatusInternalServerError, err))
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}
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}
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