http.go

/*
Copyright 2017 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"
	"io/ioutil"
	"net/http"

	"k8s.io/api/admission/v1beta1"
	"k8s.io/apimachinery/pkg/runtime"
	logf "sigs.k8s.io/controller-runtime/pkg/runtime/log"
)

var (
	// TODO(directxman12): this shouldn't be a global log
	log = logf.KBLog.WithName("admission").WithName("http-handler")
)

func (h httpHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	var body []byte
	if r.Body != nil {
		if data, err := ioutil.ReadAll(r.Body); err == nil {
			body = data
		}
	}

	// verify the content type is accurate
	contentType := r.Header.Get("Content-Type")
	if contentType != "application/json" {
		log.Error(nil, "invalid content type, expected application/json", "content type", contentType)
		return
	}

	var reviewResponse *v1beta1.AdmissionResponse
	ar := v1beta1.AdmissionReview{}
	deserializer := codecs.UniversalDeserializer()
	if _, _, err := deserializer.Decode(body, nil, &ar); err != nil {
		log.Error(err, "unable to decode request body")
		reviewResponse = ErrorResponse(err)
	} else {
		reviewResponse = h.admit(ar)
	}

	response := v1beta1.AdmissionReview{}
	if reviewResponse != nil {
		response.Response = reviewResponse
		response.Response.UID = ar.Request.UID
	}
	// reset the Object and OldObject, they are not needed in a response.
	ar.Request.Object = runtime.RawExtension{}
	ar.Request.OldObject = runtime.RawExtension{}

	resp, err := json.Marshal(response)
	if err != nil {
		log.Error(err, "unable to marshal response")
		return
	}
	if _, err := w.Write(resp); err != nil {
		log.Error(err, "unable to write response")
	}
}

type httpHandler struct {
	admit Func
}