Merge pull request #8292 from planetscale/jg_gatedebugenv

Add /debug/env for vtgate
vitessio · Jun 23, 2021 · 4385d67 · 4385d67
2 parents 7f3da8e + c01ef36
commit 4385d67
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Showing 5 changed files with 209 additions and 3 deletions.
diff --git a/go/vt/discovery/replicationlag.go b/go/vt/discovery/replicationlag.go
@@ -31,6 +31,36 @@ var (
  legacyReplicationLagAlgorithm = flag.Bool("legacy_replication_lag_algorithm", true, "use the legacy algorithm when selecting the vttablets for serving")
 )
 
+// GetLowReplicationLag getter for use by debugenv
+func GetLowReplicationLag() time.Duration {
+ return *lowReplicationLag
+}
+
+// SetLowReplicationLag setter for use by debugenv
+func SetLowReplicationLag(lag time.Duration) {
+ lowReplicationLag = &lag
+}
+
+// GetHighReplicationLagMinServing getter for use by debugenv
+func GetHighReplicationLagMinServing() time.Duration {
+ return *highReplicationLagMinServing
+}
+
+// SetHighReplicationLagMinServing setter for use by debugenv
+func SetHighReplicationLagMinServing(lag time.Duration) {
+ highReplicationLagMinServing = &lag
+}
+
+// GetMinNumTablets getter for use by debugenv
+func GetMinNumTablets() int {
+ return *minNumTablets
+}
+
+// SetMinNumTablets setter for use by debugenv
+func SetMinNumTablets(numTablets int) {
+ minNumTablets = &numTablets
+}
+
 // IsReplicationLagHigh verifies that the given LegacytabletHealth refers to a tablet with high
 // replication lag, i.e. higher than the configured discovery_low_replication_lag flag.
 func IsReplicationLagHigh(tabletHealth *TabletHealth) bool {

diff --git a/go/vt/vtgate/debugenv.go b/go/vt/vtgate/debugenv.go
@@ -0,0 +1,169 @@
+/*
+Copyright 2021 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 vtgate
+
+import (
+ "encoding/json"
+ "fmt"
+ "html"
+ "net/http"
+ "strconv"
+ "text/template"
+ "time"
+
+ "vitess.io/vitess/go/acl"
+ "vitess.io/vitess/go/vt/discovery"
+ "vitess.io/vitess/go/vt/log"
+)
+
+var (
+ debugEnvHeader = []byte(`
+ <thead><tr>
+ <th>Variable Name</th>
+ <th>Value</th>
+ <th>Action</th>
+ </tr></thead>
+ `)
+ debugEnvRow = template.Must(template.New("debugenv").Parse(`
+ <tr><form method="POST">
+ <td>{{.VarName}}</td>
+ <td>
+ <input type="hidden" name="varname" value="{{.VarName}}"></input>
+ <input type="text" name="value" value="{{.Value}}"></input>
+ </td>
+ <td><input type="submit" name="Action" value="Modify"></input></td>
+ </form></tr>
+ `))
+ gridTable = []byte(`<!DOCTYPE html>
+ <style type="text/css">
+ table.gridtable {
+ font-family: verdana,arial,sans-serif;
+ font-size: 11px;
+ border-width: 1px;
+ border-collapse: collapse; table-layout:fixed; overflow: hidden;
+ }
+ table.gridtable th {
+ border-width: 1px;
+ padding: 8px;
+ border-style: solid;
+ background-color: #dedede;
+ white-space: nowrap;
+ }
+ table.gridtable td {
+ border-width: 1px;
+ padding: 5px;
+ border-style: solid;
+ }
+ table.gridtable th {
+ padding-left: 2em;
+ padding-right: 2em;
+ }
+ </style>
+ `)
+ startTable = []byte(`
+ <table class="gridtable">
+ `)
+ endTable = []byte(`
+ </table>
+ `)
+)
+
+type envValue struct {
+ VarName string
+ Value string
+}
+
+func debugEnvHandler(vtg *VTGate, w http.ResponseWriter, r *http.Request) {
+ if err := acl.CheckAccessHTTP(r, acl.ADMIN); err != nil {
+ acl.SendError(w, err)
+ return
+ }
+
+ var msg string
+ if r.Method == "POST" {
+ varname := r.FormValue("varname")
+ value := r.FormValue("value")
+ setIntVal := func(f func(int)) {
+ ival, err := strconv.Atoi(value)
+ if err != nil {
+ msg = fmt.Sprintf("Failed setting value for %v: %v", varname, err)
+ return
+ }
+ f(ival)
+ msg = fmt.Sprintf("Setting %v to: %v", varname, value)
+ }
+ setDurationVal := func(f func(time.Duration)) {
+ durationVal, err := time.ParseDuration(value)
+ if err != nil {
+ msg = fmt.Sprintf("Failed setting value for %v: %v", varname, err)
+ return
+ }
+ f(durationVal)
+ msg = fmt.Sprintf("Setting %v to: %v", varname, value)
+ }
+ switch varname {
+ case "discovery_low_replication_lag":
+ setDurationVal(discovery.SetLowReplicationLag)
+ case "discovery_high_replication_lag_minimum_serving":
+ setDurationVal(discovery.SetHighReplicationLagMinServing)
+ case "min_num_tablets":
+ setIntVal(discovery.SetMinNumTablets)
+ }
+ }
+
+ var vars []envValue
+ addIntVar := func(varname string, f func() int) {
+ vars = append(vars, envValue{
+ VarName: varname,
+ Value: fmt.Sprintf("%v", f()),
+ })
+ }
+ addDurationVar := func(varname string, f func() time.Duration) {
+ vars = append(vars, envValue{
+ VarName: varname,
+ Value: fmt.Sprintf("%v", f()),
+ })
+ }
+ addDurationVar("discovery_low_replication_lag", discovery.GetLowReplicationLag)
+ addDurationVar("discovery_high_replication_lag_minimum_serving", discovery.GetHighReplicationLagMinServing)
+ addIntVar("min_num_tablets", discovery.GetMinNumTablets)
+
+ format := r.FormValue("format")
+ if format == "json" {
+ mvars := make(map[string]string)
+ for _, v := range vars {
+ mvars[v.VarName] = v.Value
+ }
+ w.Header().Set("Content-Type", "application/json")
+ _ = json.NewEncoder(w).Encode(mvars)
+ return
+ }
+
+ w.Write(gridTable)
+ w.Write([]byte("<h3>Internal Variables</h3>\n"))
+ if msg != "" {
+ w.Write([]byte(fmt.Sprintf("<b>%s</b><br /><br />\n", html.EscapeString(msg))))
+ }
+ w.Write(startTable)
+ w.Write(debugEnvHeader)
+ for _, v := range vars {
+ if err := debugEnvRow.Execute(w, v); err != nil {
+ log.Errorf("debugenv: couldn't execute template: %v", err)
+ }
+ }
+ w.Write(endTable)
+}
diff --git a/go/vt/vtgate/executor_scatter_stats.go b/go/vt/vtgate/executor_scatter_stats.go
@@ -134,7 +134,7 @@ func (e *Executor) WriteScatterStats(w http.ResponseWriter) {
  }
 
  t := template.New("template")
- t, err = t.Parse(html)
+ t, err = t.Parse(statsHTML)
  if err != nil {
  http.Error(w, err.Error(), 500)
  return
@@ -153,7 +153,7 @@ func (e *Executor) WriteScatterStats(w http.ResponseWriter) {
 
 }
 
-const html = `
+const statsHTML = `
 <thead>
  <tr>
  <th>Query</th>

diff --git a/go/vt/vtgate/vtgate.go b/go/vt/vtgate/vtgate.go
@@ -273,6 +273,7 @@ func Init(ctx context.Context, serv srvtopo.Server, cell string, tabletTypesToWa
  }
  })
  rpcVTGate.registerDebugHealthHandler()
+ rpcVTGate.registerDebugEnvHandler()
  err := initQueryLogger(rpcVTGate)
  if err != nil {
  log.Fatalf("error initializing query logger: %v", err)
@@ -321,6 +322,12 @@ func resolveAndLoadKeyspace(ctx context.Context, srvResolver *srvtopo.Resolver,
  }
 }
 
+func (vtg *VTGate) registerDebugEnvHandler() {
+ http.HandleFunc("/debug/env", func(w http.ResponseWriter, r *http.Request) {
+ debugEnvHandler(vtg, w, r)
+ })
+}
+
 func (vtg *VTGate) registerDebugHealthHandler() {
  http.HandleFunc("/debug/health", func(w http.ResponseWriter, r *http.Request) {
  if err := acl.CheckAccessHTTP(r, acl.MONITORING); err != nil {

diff --git a/go/vt/vttablet/tabletserver/debugenv.go b/go/vt/vttablet/tabletserver/debugenv.go
@@ -169,7 +169,7 @@ func debugEnvHandler(tsv *TabletServer, w http.ResponseWriter, r *http.Request)
  w.Write(debugEnvHeader)
  for _, v := range vars {
  if err := debugEnvRow.Execute(w, v); err != nil {
- log.Errorf("queryz: couldn't execute template: %v", err)
+ log.Errorf("debugenv: couldn't execute template: %v", err)
  }
  }
  w.Write(endTable)