2019-01-12 04:58:27 +00:00
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/*
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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 routes
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import (
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"fmt"
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"html/template"
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"io/ioutil"
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"net/http"
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"path"
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"sync"
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"k8s.io/klog"
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"k8s.io/apiserver/pkg/server/mux"
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)
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var (
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lock = &sync.RWMutex{}
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registeredFlags = map[string]debugFlag{}
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)
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// DebugFlags adds handlers for flags under /debug/flags.
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type DebugFlags struct {
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}
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// Install registers the APIServer's flags handler.
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func (f DebugFlags) Install(c *mux.PathRecorderMux, flag string, handler func(http.ResponseWriter, *http.Request)) {
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c.UnlistedHandle("/debug/flags", http.HandlerFunc(f.Index))
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c.UnlistedHandlePrefix("/debug/flags/", http.HandlerFunc(f.Index))
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url := path.Join("/debug/flags", flag)
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c.UnlistedHandleFunc(url, handler)
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f.addFlag(flag)
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}
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// Index responds with the `/debug/flags` request.
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// For example, "/debug/flags/v" serves the "--v" flag.
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// Index responds to a request for "/debug/flags/" with an HTML page
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// listing the available flags.
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func (f DebugFlags) Index(w http.ResponseWriter, r *http.Request) {
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lock.RLock()
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defer lock.RUnlock()
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if err := indexTmpl.Execute(w, registeredFlags); err != nil {
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klog.Error(err)
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}
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}
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var indexTmpl = template.Must(template.New("index").Parse(`<html>
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<head>
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<title>/debug/flags/</title>
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</head>
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<body>
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/debug/flags/<br>
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<br>
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flags:<br>
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<table>
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{{range .}}
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<tr>{{.Flag}}<br>
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{{end}}
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</table>
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<br>
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full flags configurable<br>
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</body>
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</html>
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`))
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type debugFlag struct {
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Flag string
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}
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func (f DebugFlags) addFlag(flag string) {
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lock.Lock()
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defer lock.Unlock()
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registeredFlags[flag] = debugFlag{flag}
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}
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// StringFlagSetterFunc is a func used for setting string type flag.
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type StringFlagSetterFunc func(string) (string, error)
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// StringFlagPutHandler wraps an http Handler to set string type flag.
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func StringFlagPutHandler(setter StringFlagSetterFunc) http.HandlerFunc {
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return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
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switch {
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case req.Method == "PUT":
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body, err := ioutil.ReadAll(req.Body)
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if err != nil {
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writePlainText(http.StatusBadRequest, "error reading request body: "+err.Error(), w)
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return
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}
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defer req.Body.Close()
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response, err := setter(string(body))
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if err != nil {
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writePlainText(http.StatusBadRequest, err.Error(), w)
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return
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}
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writePlainText(http.StatusOK, response, w)
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return
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default:
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writePlainText(http.StatusNotAcceptable, "unsupported http method", w)
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return
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}
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})
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}
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// writePlainText renders a simple string response.
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func writePlainText(statusCode int, text string, w http.ResponseWriter) {
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w.Header().Set("Content-Type", "text/plain")
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2019-12-12 01:27:03 +00:00
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w.Header().Set("X-Content-Type-Options", "nosniff")
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2019-01-12 04:58:27 +00:00
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w.WriteHeader(statusCode)
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fmt.Fprintln(w, text)
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}
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