vtctld: proxy must update target URLs

go/vt/vtctld/api.go

@@ -29,6 +29,7 @@ import (
 	"golang.org/x/net/context"
 
 	"vitess.io/vitess/go/acl"
+	"vitess.io/vitess/go/netutil"
 	"vitess.io/vitess/go/vt/log"
 	"vitess.io/vitess/go/vt/logutil"
 	"vitess.io/vitess/go/vt/schemamanager"
@@ -48,6 +49,7 @@ import (
 var (
 	localCell        = flag.String("cell", "", "cell to use")
 	showTopologyCRUD = flag.Bool("vtctld_show_topology_crud", true, "Controls the display of the CRUD topology actions in the vtctld UI.")
+	proxyTablets     = flag.Bool("proxy_tablets", false, "Setting this true will make vtctld proxy the tablet status instead of redirecting to them")
 )
 
 // This file implements a REST-style API for the vtctld web interface.
@@ -406,13 +408,10 @@ func initAPI(ctx context.Context, ts *topo.Server, actions *ActionRepository, re
 			MysqlPort:           t.MysqlPort,
 			MasterTermStartTime: t.MasterTermStartTime,
 		}
-		tabletPath = fmt.Sprintf("http://%s:%d", t.Tablet.Hostname, t.PortMap["vt"])
 		if *proxyTablets {
-			tabletID := fmt.Sprintf("%s-%d", t.Tablet.Alias.Cell, t.Tablet.Alias.Uid)
-			addRemote(tabletID, tabletPath)
-			tab.URL = fmt.Sprintf("/vttablet/%s-%d", t.Tablet.Alias.Cell, t.Tablet.Alias.Uid)
+			tab.URL = fmt.Sprintf("/vttablet/%s-%d", t.Alias.Cell, t.Alias.Uid)
 		} else {
-			tab.URL = tabletPath
+			tab.URL = "http://" + netutil.JoinHostPort(t.Hostname, t.PortMap["vt"])
 		}
 		return tab, nil
 	})

go/vt/vtctld/redirection.go

@@ -0,0 +1,87 @@
+/*
+Copyright 2020 The Vitess 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 vtctld
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/http/httputil"
+	"strings"
+
+	"vitess.io/vitess/go/netutil"
+	"vitess.io/vitess/go/vt/log"
+	"vitess.io/vitess/go/vt/topo"
+	"vitess.io/vitess/go/vt/topo/topoproto"
+)
+
+func initVTTabletRedirection(ts *topo.Server) {
+	http.HandleFunc("/vttablet/", func(w http.ResponseWriter, r *http.Request) {
+		splits := strings.SplitN(r.URL.Path, "/", 4)
+		if len(splits) < 4 {
+			log.Errorf("Invalid URL: %v", r.URL)
+			http.NotFound(w, r)
+			return
+		}
+		tabletID := splits[2]
+		tabletAlias, err := topoproto.ParseTabletAlias(tabletID)
+		if err != nil {
+			log.Errorf("Error parsting tablet alias %v: %v", tabletID, err)
+			http.NotFound(w, r)
+			return
+		}
+		tablet, err := ts.GetTablet(r.Context(), tabletAlias)
+		if err != nil {
+			log.Errorf("Error fetching tablet %v: %v", splits[2], err)
+			http.NotFound(w, r)
+			return
+		}
+		if tablet.Hostname == "" || tablet.PortMap["vt"] == 0 {
+			log.Errorf("Invalid host/port: %s %d", tablet.Hostname, tablet.PortMap["vt"])
+			http.NotFound(w, r)
+			return
+		}
+
+		rp := &httputil.ReverseProxy{}
+		rp.Director = func(req *http.Request) {
+			req.URL.Scheme = "http"
+			req.URL.Host = netutil.JoinHostPort(tablet.Hostname, tablet.PortMap["vt"])
+			req.URL.Path = "/" + splits[3]
+		}
+
+		prefixPath := fmt.Sprintf("/vttablet/%s/", tabletID)
+		rp.ModifyResponse = func(r *http.Response) error {
+			b, _ := ioutil.ReadAll(r.Body)
+			b = bytes.ReplaceAll(b, []byte(`href="/`), []byte(fmt.Sprintf(`href="%s`, prefixPath)))
+			b = bytes.ReplaceAll(b, []byte(`href=/`), []byte(fmt.Sprintf(`href=%s`, prefixPath)))
+			r.Body = ioutil.NopCloser(bytes.NewBuffer(b))
+			r.Header["Content-Length"] = []string{fmt.Sprint(len(b))}
+
+			// Don't forget redirects
+			loc := r.Header["Location"]
+			for i, v := range loc {
+				if strings.HasPrefix(v, "/") {
+					loc[i] = strings.Replace(v, "/", prefixPath, 1)
+				}
+			}
+			return nil
+		}
+
+		rp.ServeHTTP(w, r)
+	})
+}

go/vt/vtctld/vtctld.go

@@ -178,4 +178,7 @@ func InitVtctld(ts *topo.Server) {
 
 	// Init workflow manager.
 	initWorkflowManager(ts)
+
+	// Setup reverse proxy for all vttablets through /vttablet/.
+	initVTTabletRedirection(ts)
 }