Initial v1.0.0 commit

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

@@ -0,0 +1,144 @@
+/*
+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 (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+
+	v1 "k8s.io/api/admission/v1"
+	"k8s.io/api/admission/v1beta1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/runtime/serializer"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+)
+
+var admissionScheme = runtime.NewScheme()
+var admissionCodecs = serializer.NewCodecFactory(admissionScheme)
+
+func init() {
+	utilruntime.Must(v1.AddToScheme(admissionScheme))
+	utilruntime.Must(v1beta1.AddToScheme(admissionScheme))
+}
+
+var _ http.Handler = &Webhook{}
+
+func (wh *Webhook) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	var body []byte
+	var err error
+
+	var reviewResponse Response
+	if r.Body != nil {
+		if body, err = ioutil.ReadAll(r.Body); err != nil {
+			wh.log.Error(err, "unable to read the body from the incoming request")
+			reviewResponse = Errored(http.StatusBadRequest, err)
+			wh.writeResponse(w, reviewResponse)
+			return
+		}
+	} else {
+		err = errors.New("request body is empty")
+		wh.log.Error(err, "bad request")
+		reviewResponse = Errored(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, expected application/json", contentType)
+		wh.log.Error(err, "unable to process a request with an unknown content type", "content type", contentType)
+		reviewResponse = Errored(http.StatusBadRequest, err)
+		wh.writeResponse(w, reviewResponse)
+		return
+	}
+
+	// Both v1 and v1beta1 AdmissionReview types are exactly the same, so the v1beta1 type can
+	// be decoded into the v1 type. However the runtime codec's decoder guesses which type to
+	// decode into by type name if an Object's TypeMeta isn't set. By setting TypeMeta of an
+	// unregistered type to the v1 GVK, the decoder will coerce a v1beta1 AdmissionReview to v1.
+	// The actual AdmissionReview GVK will be used to write a typed response in case the
+	// webhook config permits multiple versions, otherwise this response will fail.
+	req := Request{}
+	ar := unversionedAdmissionReview{}
+	// avoid an extra copy
+	ar.Request = &req.AdmissionRequest
+	ar.SetGroupVersionKind(v1.SchemeGroupVersion.WithKind("AdmissionReview"))
+	_, actualAdmRevGVK, err := admissionCodecs.UniversalDeserializer().Decode(body, nil, &ar)
+	if err != nil {
+		wh.log.Error(err, "unable to decode the request")
+		reviewResponse = Errored(http.StatusBadRequest, err)
+		wh.writeResponse(w, reviewResponse)
+		return
+	}
+	wh.log.V(1).Info("received request", "UID", req.UID, "kind", req.Kind, "resource", req.Resource)
+
+	// TODO: add panic-recovery for Handle
+	reviewResponse = wh.Handle(r.Context(), req)
+	wh.writeResponseTyped(w, reviewResponse, actualAdmRevGVK)
+}
+
+// writeResponse writes response to w generically, i.e. without encoding GVK information.
+func (wh *Webhook) writeResponse(w io.Writer, response Response) {
+	wh.writeAdmissionResponse(w, v1.AdmissionReview{Response: &response.AdmissionResponse})
+}
+
+// writeResponseTyped writes response to w with GVK set to admRevGVK, which is necessary
+// if multiple AdmissionReview versions are permitted by the webhook.
+func (wh *Webhook) writeResponseTyped(w io.Writer, response Response, admRevGVK *schema.GroupVersionKind) {
+	ar := v1.AdmissionReview{
+		Response: &response.AdmissionResponse,
+	}
+	// Default to a v1 AdmissionReview, otherwise the API server may not recognize the request
+	// if multiple AdmissionReview versions are permitted by the webhook config.
+	// TODO(estroz): this should be configurable since older API servers won't know about v1.
+	if admRevGVK == nil || *admRevGVK == (schema.GroupVersionKind{}) {
+		ar.SetGroupVersionKind(v1.SchemeGroupVersion.WithKind("AdmissionReview"))
+	} else {
+		ar.SetGroupVersionKind(*admRevGVK)
+	}
+	wh.writeAdmissionResponse(w, ar)
+}
+
+// writeAdmissionResponse writes ar to w.
+func (wh *Webhook) writeAdmissionResponse(w io.Writer, ar v1.AdmissionReview) {
+	err := json.NewEncoder(w).Encode(ar)
+	if err != nil {
+		wh.log.Error(err, "unable to encode the response")
+		wh.writeResponse(w, Errored(http.StatusInternalServerError, err))
+	} else {
+		res := ar.Response
+		if log := wh.log; log.V(1).Enabled() {
+			if res.Result != nil {
+				log = log.WithValues("code", res.Result.Code, "reason", res.Result.Reason)
+			}
+			log.V(1).Info("wrote response", "UID", res.UID, "allowed", res.Allowed)
+		}
+	}
+}
+
+// unversionedAdmissionReview is used to decode both v1 and v1beta1 AdmissionReview types.
+type unversionedAdmissionReview struct {
+	v1.AdmissionReview
+}
+
+var _ runtime.Object = &unversionedAdmissionReview{}