mirror of https://github.com/k3s-io/k3s
156 lines
4.0 KiB
Go
156 lines
4.0 KiB
Go
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/*
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Copyright 2014 Google Inc. All rights reserved.
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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 apiserver
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import (
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"bytes"
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"fmt"
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"io/ioutil"
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"net"
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"net/http"
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"net/http/httputil"
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"net/url"
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"strings"
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"code.google.com/p/go.net/html"
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"code.google.com/p/go.net/html/atom"
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"github.com/golang/glog"
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)
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func (server *APIServer) handleProxyMinion(w http.ResponseWriter, req *http.Request) {
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minionPrefix := "/proxy/minion/"
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if !strings.HasPrefix(req.URL.Path, minionPrefix) {
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notFound(w, req)
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return
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}
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path := req.URL.Path[len(minionPrefix):]
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rawQuery := req.URL.RawQuery
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// Expect path as: ${minion}/${query_to_minion}
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// and query_to_minion can be any query that kubelet will accept.
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//
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// For example:
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// To query stats of a minion or a pod or a container,
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// path string can be ${minion}/stats/<podid>/<containerName> or
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// ${minion}/podInfo?podID=<podid>
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//
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// To query logs on a minion, path string can be:
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// ${minion}/logs/
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idx := strings.Index(path, "/")
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minionHost := path[:idx]
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_, port, _ := net.SplitHostPort(minionHost)
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if port == "" {
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// Couldn't retrieve port information
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// TODO: Retrieve port info from a common object
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minionHost += ":10250"
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}
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minionPath := path[idx:]
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minionURL := &url.URL{
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Scheme: "http",
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Host: minionHost,
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}
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newReq, err := http.NewRequest("GET", minionPath+"?"+rawQuery, nil)
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if err != nil {
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glog.Errorf("Failed to create request: %s", err)
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}
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proxy := httputil.NewSingleHostReverseProxy(minionURL)
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proxy.Transport = &minionTransport{}
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proxy.ServeHTTP(w, newReq)
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}
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type minionTransport struct{}
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func (t *minionTransport) RoundTrip(req *http.Request) (*http.Response, error) {
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resp, err := http.DefaultTransport.RoundTrip(req)
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if err != nil && strings.Contains(err.Error(), "connection refused") {
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message := fmt.Sprintf("Failed to connect to minion:%s", req.URL.Host)
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resp = &http.Response{
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StatusCode: http.StatusServiceUnavailable,
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Body: ioutil.NopCloser(strings.NewReader(message)),
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}
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return resp, nil
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}
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if strings.Contains(resp.Header.Get("Content-Type"), "text/plain") {
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// Do nothing, simply pass through
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return resp, err
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}
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resp, err = t.ProcessResponse(req, resp)
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return resp, err
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}
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func (t *minionTransport) ProcessResponse(req *http.Request, resp *http.Response) (*http.Response, error) {
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body, err := ioutil.ReadAll(resp.Body)
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if err != nil {
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// copying the response body did not work
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return nil, err
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}
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bodyNode := &html.Node{
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Type: html.ElementNode,
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Data: "body",
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DataAtom: atom.Body,
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}
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nodes, err := html.ParseFragment(bytes.NewBuffer(body), bodyNode)
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if err != nil {
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glog.Errorf("Failed to found <body> node: %v", err)
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return resp, err
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}
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// Define the method to traverse the doc tree and update href node to
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// point to correct minion
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var updateHRef func(*html.Node)
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updateHRef = func(n *html.Node) {
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if n.Type == html.ElementNode && n.Data == "a" {
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for i, attr := range n.Attr {
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if attr.Key == "href" {
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Url := &url.URL{
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Path: "/proxy/minion/" + req.URL.Host + req.URL.Path + attr.Val,
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}
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n.Attr[i].Val = Url.String()
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break
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}
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}
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}
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for c := n.FirstChild; c != nil; c = c.NextSibling {
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updateHRef(c)
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}
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}
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newContent := &bytes.Buffer{}
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for _, n := range nodes {
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updateHRef(n)
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err = html.Render(newContent, n)
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if err != nil {
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glog.Errorf("Failed to render: %v", err)
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}
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}
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resp.Body = ioutil.NopCloser(newContent)
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// Update header node with new content-length
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// TODO: Remove any hash/signature headers here?
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resp.Header.Del("Content-Length")
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resp.ContentLength = int64(newContent.Len())
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return resp, err
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}
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