apiserver/pkg/server/handler.go

129 lines
4.8 KiB
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 server
import (
"bytes"
"fmt"
"net/http"
rt "runtime"
"sort"
"github.com/emicklei/go-restful"
"github.com/golang/glog"
apierrors "k8s.io/apimachinery/pkg/api/errors"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apiserver/pkg/endpoints/handlers/responsewriters"
"k8s.io/apiserver/pkg/server/mux"
genericmux "k8s.io/apiserver/pkg/server/mux"
)
// APIServerHandlers holds the different http.Handlers used by the API server.
// This includes the full handler chain, the gorestful handler (used for the API) which falls through to the postGoRestful handler
// and the postGoRestful handler (which can contain a fallthrough of its own)
type APIServerHandler struct {
// FullHandlerChain is the one that is eventually served with. It should include the full filter
// chain and then call the GoRestfulContainer.
FullHandlerChain http.Handler
// The registered APIs
GoRestfulContainer *restful.Container
// PostGoRestfulMux is the final HTTP handler in the chain.
// It comes after all filters and the API handling
PostGoRestfulMux *mux.PathRecorderMux
}
// HandlerChainBuilderFn is used to wrap the GoRestfulContainer handler using the provided handler chain.
// It is normally used to apply filtering like authentication and authorization
type HandlerChainBuilderFn func(apiHandler http.Handler) http.Handler
func NewAPIServerHandler(s runtime.NegotiatedSerializer, handlerChainBuilder HandlerChainBuilderFn, notFoundHandler http.Handler) *APIServerHandler {
postGoRestfulMux := genericmux.NewPathRecorderMux()
if notFoundHandler != nil {
postGoRestfulMux.NotFoundHandler(notFoundHandler)
}
gorestfulContainer := restful.NewContainer()
gorestfulContainer.ServeMux = http.NewServeMux()
gorestfulContainer.Router(restful.CurlyRouter{}) // e.g. for proxy/{kind}/{name}/{*}
gorestfulContainer.RecoverHandler(func(panicReason interface{}, httpWriter http.ResponseWriter) {
logStackOnRecover(s, panicReason, httpWriter)
})
gorestfulContainer.ServiceErrorHandler(func(serviceErr restful.ServiceError, request *restful.Request, response *restful.Response) {
serviceErrorHandler(s, serviceErr, request, response)
})
// register the defaultHandler for everything. This will allow an unhandled request to fall through to another handler instead of
// ending up with a forced 404
gorestfulContainer.Handle("/", postGoRestfulMux)
return &APIServerHandler{
FullHandlerChain: handlerChainBuilder(gorestfulContainer.ServeMux),
GoRestfulContainer: gorestfulContainer,
PostGoRestfulMux: postGoRestfulMux,
}
}
// ListedPaths returns the paths that should be shown under /
func (a *APIServerHandler) ListedPaths() []string {
var handledPaths []string
// Extract the paths handled using restful.WebService
for _, ws := range a.GoRestfulContainer.RegisteredWebServices() {
handledPaths = append(handledPaths, ws.RootPath())
}
handledPaths = append(handledPaths, a.PostGoRestfulMux.ListedPaths()...)
sort.Strings(handledPaths)
return handledPaths
}
//TODO: Unify with RecoverPanics?
func logStackOnRecover(s runtime.NegotiatedSerializer, panicReason interface{}, w http.ResponseWriter) {
var buffer bytes.Buffer
buffer.WriteString(fmt.Sprintf("recover from panic situation: - %v\r\n", panicReason))
for i := 2; ; i++ {
_, file, line, ok := rt.Caller(i)
if !ok {
break
}
buffer.WriteString(fmt.Sprintf(" %s:%d\r\n", file, line))
}
glog.Errorln(buffer.String())
headers := http.Header{}
if ct := w.Header().Get("Content-Type"); len(ct) > 0 {
headers.Set("Accept", ct)
}
responsewriters.ErrorNegotiated(apierrors.NewGenericServerResponse(http.StatusInternalServerError, "", schema.GroupResource{}, "", "", 0, false), s, schema.GroupVersion{}, w, &http.Request{Header: headers})
}
func serviceErrorHandler(s runtime.NegotiatedSerializer, serviceErr restful.ServiceError, request *restful.Request, resp *restful.Response) {
responsewriters.ErrorNegotiated(
apierrors.NewGenericServerResponse(serviceErr.Code, "", schema.GroupResource{}, "", serviceErr.Message, 0, false),
s,
schema.GroupVersion{},
resp,
request.Request,
)
}
// ServeHTTP makes it an http.Handler
func (a *APIServerHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
a.FullHandlerChain.ServeHTTP(w, r)
}