Exemplo n.º 1
0
func (agent *ActionAgent) allowQueries(tablet *topo.Tablet) error {
	if agent.DBConfigs == nil {
		// test instance, do nothing
		return nil
	}

	// if the query service is already running, we're not starting it again
	if tabletserver.SqlQueryRpcService.GetState() == "SERVING" {
		return nil
	}

	// Update our DB config to match the info we have in the tablet
	if agent.DBConfigs.App.DbName == "" {
		agent.DBConfigs.App.DbName = tablet.DbName()
	}
	agent.DBConfigs.App.Keyspace = tablet.Keyspace
	agent.DBConfigs.App.Shard = tablet.Shard

	qrs, err := agent.createQueryRules(tablet)
	if err != nil {
		return err
	}

	return tabletserver.AllowQueries(&agent.DBConfigs.App, agent.SchemaOverrides, qrs, agent.Mysqld, false)
}
Exemplo n.º 2
0
func main() {
	flag.Parse()
	servenv.Init()
	defer servenv.Close()

	unmarshalFile(*dbConfigFile, &dbconfig)
	log.Infof("dbconfig: %s\n", dbconfig)

	unmarshalFile(*overridesFile, &schemaOverrides)
	data, _ := json.MarshalIndent(schemaOverrides, "", "  ")
	log.Infof("schemaOverrides: %s\n", data)

	ts.InitQueryService()

	ts.AllowQueries(dbconfig, schemaOverrides, ts.LoadCustomRules())

	servenv.ServeRPC()

	log.Infof("starting vtocc %v", *port)
	s := proc.ListenAndServe(fmt.Sprintf("%v", *port))

	// A SIGUSR1 means that we're restarting
	if s == syscall.SIGUSR1 {
		// Give some time for the other process
		// to pick up the listeners
		time.Sleep(5 * time.Millisecond)
		ts.DisallowQueries(true)
	} else {
		ts.DisallowQueries(false)
	}
}
Exemplo n.º 3
0
func main() {
	dbconfigs.RegisterFlags()
	flag.Parse()
	servenv.Init()

	dbConfigs, err := dbconfigs.Init("")
	if err != nil {
		log.Fatalf("Cannot initialize App dbconfig: %v", err)
	}
	if *enableRowcache {
		dbConfigs.App.EnableRowcache = true
		if *enableInvalidator {
			dbConfigs.App.EnableInvalidator = true
		}
	}
	mycnf := &mysqlctl.Mycnf{BinLogPath: *binlogPath}
	mysqld := mysqlctl.NewMysqld(mycnf, &dbConfigs.Dba, &dbConfigs.Repl)

	unmarshalFile(*overridesFile, &schemaOverrides)
	data, _ := json.MarshalIndent(schemaOverrides, "", "  ")
	log.Infof("schemaOverrides: %s\n", data)

	ts.InitQueryService()

	ts.AllowQueries(&dbConfigs.App, schemaOverrides, ts.LoadCustomRules(), mysqld)

	log.Infof("starting vtocc %v", *servenv.Port)
	servenv.OnClose(func() {
		time.Sleep(5 * time.Millisecond)
		ts.DisallowQueries()
	})
	servenv.Run()
}
Exemplo n.º 4
0
func main() {
	defaultDBConfig := dbconfigs.DefaultDBConfigs.App
	defaultDBConfig.Host = "localhost"
	dbconfigs.RegisterAppFlags(defaultDBConfig)
	flag.Parse()
	servenv.Init()

	dbConfig, err := dbconfigs.InitApp("")
	if err != nil {
		log.Fatalf("Cannot initialize App dbconfig: %v", err)
	}

	unmarshalFile(*overridesFile, &schemaOverrides)
	data, _ := json.MarshalIndent(schemaOverrides, "", "  ")
	log.Infof("schemaOverrides: %s\n", data)

	ts.InitQueryService()

	ts.AllowQueries(dbConfig, schemaOverrides, ts.LoadCustomRules())

	log.Infof("starting vtocc %v", *port)
	servenv.OnClose(func() {
		time.Sleep(5 * time.Millisecond)
		ts.DisallowQueries()
	})
	servenv.Run(*port)
}
Exemplo n.º 5
0
func (agent *ActionAgent) allowQueries(tablet *topo.Tablet) error {
	// if the query service is already running, we're not starting it again
	if tabletserver.SqlQueryRpcService.GetState() == "SERVING" {
		return nil
	}

	// Update our DB config to match the info we have in the tablet
	if agent.DBConfigs.App.DbName == "" {
		agent.DBConfigs.App.DbName = tablet.DbName()
	}
	agent.DBConfigs.App.Keyspace = tablet.Keyspace
	agent.DBConfigs.App.Shard = tablet.Shard
	if tablet.Type != topo.TYPE_MASTER {
		agent.DBConfigs.App.EnableInvalidator = true
	} else {
		agent.DBConfigs.App.EnableInvalidator = false
	}

	// Compute the query rules that match the tablet record
	qrs := tabletserver.LoadCustomRules()
	if tablet.KeyRange.IsPartial() {
		qr := tabletserver.NewQueryRule("enforce keyspace_id range", "keyspace_id_not_in_range", tabletserver.QR_FAIL)
		qr.AddPlanCond(planbuilder.PLAN_INSERT_PK)
		err := qr.AddBindVarCond("keyspace_id", true, true, tabletserver.QR_NOTIN, tablet.KeyRange)
		if err != nil {
			log.Warningf("Unable to add keyspace rule: %v", err)
		} else {
			qrs.Add(qr)
		}
	}
	if len(tablet.BlacklistedTables) > 0 {
		// tables, first resolve wildcards
		tables, err := agent.Mysqld.ResolveTables(tablet.DbName(), tablet.BlacklistedTables)
		if err != nil {
			log.Warningf("Unable to resolve blacklisted tables: %v", err)
		} else {
			log.Infof("Blacklisting tables %v", strings.Join(tables, ", "))
			qr := tabletserver.NewQueryRule("enforce blacklisted tables", "blacklisted_table", tabletserver.QR_FAIL_RETRY)
			for _, t := range tables {
				qr.AddTableCond(t)
			}
			qrs.Add(qr)
		}
	}

	return tabletserver.AllowQueries(&agent.DBConfigs.App, agent.SchemaOverrides, qrs, agent.Mysqld, false)
}
Exemplo n.º 6
0
func main() {
	dbconfigs.RegisterFlags()
	flag.Parse()
	if len(flag.Args()) > 0 {
		flag.Usage()
		log.Fatalf("vtocc doesn't take any positional arguments")
	}
	servenv.Init()

	dbConfigs, err := dbconfigs.Init("")
	if err != nil {
		log.Fatalf("Cannot initialize App dbconfig: %v", err)
	}
	if *enableRowcache {
		dbConfigs.App.EnableRowcache = true
		if *enableInvalidator {
			dbConfigs.App.EnableInvalidator = true
		}
	}
	mycnf := &mysqlctl.Mycnf{BinLogPath: *binlogPath}
	mysqld := mysqlctl.NewMysqld("Dba", mycnf, &dbConfigs.Dba, &dbConfigs.Repl)

	unmarshalFile(*overridesFile, &schemaOverrides)
	data, _ := json.MarshalIndent(schemaOverrides, "", "  ")
	log.Infof("schemaOverrides: %s\n", data)

	if *tableAclConfig != "" {
		tableacl.Init(*tableAclConfig)
	}
	tabletserver.InitQueryService()

	err = tabletserver.AllowQueries(&dbConfigs.App, schemaOverrides, tabletserver.LoadCustomRules(), mysqld, true)
	if err != nil {
		return
	}

	log.Infof("starting vtocc %v", *servenv.Port)
	servenv.OnTerm(func() {
		tabletserver.DisallowQueries()
		mysqld.Close()
	})
	servenv.RunDefault()
}
Exemplo n.º 7
0
func main() {
	dbCredentialsFile := dbconfigs.RegisterAppFlags(DefaultDBConfig)
	flag.Parse()
	servenv.Init()

	dbConfigs, _ := dbconfigs.Init("", *dbCredentialsFile)

	unmarshalFile(*overridesFile, &schemaOverrides)
	data, _ := json.MarshalIndent(schemaOverrides, "", "  ")
	log.Infof("schemaOverrides: %s\n", data)

	ts.InitQueryService()

	ts.AllowQueries(dbConfigs.App, schemaOverrides, ts.LoadCustomRules())

	log.Infof("starting vtocc %v", *port)
	servenv.OnClose(func() {
		time.Sleep(5 * time.Millisecond)
		ts.DisallowQueries()
	})
	servenv.Run(*port)
}
Exemplo n.º 8
0
// InitAgent initializes the agent within vttablet.
func InitAgent(
	tabletAlias topo.TabletAlias,
	dbcfgs dbconfigs.DBConfigs,
	mycnf *mysqlctl.Mycnf,
	dbConfigsFile, dbCredentialsFile string,
	port, securePort int,
	mycnfFile, overridesFile string) (err error) {
	schemaOverrides := loadSchemaOverrides(overridesFile)

	topoServer := topo.GetServer()

	// Start the binlog server service, disabled at start.
	binlogServer = mysqlctl.NewBinlogServer(mycnf)
	mysqlctl.RegisterBinlogServerService(binlogServer)

	// Start the binlog player services, not playing at start.
	binlogPlayerMap = NewBinlogPlayerMap(topoServer, &dbcfgs.Dba)
	RegisterBinlogPlayerMap(binlogPlayerMap)

	// Compute the bind addresses
	bindAddr := fmt.Sprintf(":%v", port)
	secureAddr := ""
	if securePort != 0 {
		secureAddr = fmt.Sprintf(":%v", securePort)
	}

	exportedType := expvar.NewString("tablet-type")

	// Action agent listens to changes in zookeeper and makes
	// modifications to this tablet.
	agent, err = tm.NewActionAgent(topoServer, tabletAlias, mycnfFile, dbConfigsFile, dbCredentialsFile)
	if err != nil {
		return err
	}
	agent.AddChangeCallback(func(oldTablet, newTablet topo.Tablet) {
		if newTablet.IsServingType() {
			if dbcfgs.App.Dbname == "" {
				dbcfgs.App.Dbname = newTablet.DbName()
			}
			dbcfgs.App.KeyRange = newTablet.KeyRange
			dbcfgs.App.Keyspace = newTablet.Keyspace
			dbcfgs.App.Shard = newTablet.Shard
			// Transitioning from replica to master, first disconnect
			// existing connections. "false" indicateds that clients must
			// re-resolve their endpoint before reconnecting.
			if newTablet.Type == topo.TYPE_MASTER && oldTablet.Type != topo.TYPE_MASTER {
				ts.DisallowQueries(false)
			}
			qrs := ts.LoadCustomRules()
			if dbcfgs.App.KeyRange.IsPartial() {
				qr := ts.NewQueryRule("enforce keyspace_id range", "keyspace_id_not_in_range", ts.QR_FAIL_QUERY)
				qr.AddPlanCond(sqlparser.PLAN_INSERT_PK)
				err = qr.AddBindVarCond("keyspace_id", true, true, ts.QR_NOTIN, dbcfgs.App.KeyRange)
				if err != nil {
					log.Warningf("Unable to add keyspace rule: %v", err)
				} else {
					qrs.Add(qr)
				}
			}
			ts.AllowQueries(dbcfgs.App, schemaOverrides, qrs)
			mysqlctl.EnableUpdateStreamService(string(newTablet.Type), dbcfgs)
			if newTablet.Type != topo.TYPE_MASTER {
				ts.StartRowCacheInvalidation()
			}
		} else {
			ts.DisallowQueries(false)
			ts.StopRowCacheInvalidation()
			mysqlctl.DisableUpdateStreamService()
		}

		exportedType.Set(string(newTablet.Type))

		// BinlogServer is only enabled for replicas
		if newTablet.Type == topo.TYPE_REPLICA {
			if !mysqlctl.IsBinlogServerEnabled(binlogServer) {
				mysqlctl.EnableBinlogServerService(binlogServer, dbcfgs.App.Dbname)
			}
		} else {
			if mysqlctl.IsBinlogServerEnabled(binlogServer) {
				mysqlctl.DisableBinlogServerService(binlogServer)
			}
		}

		// See if we need to start or stop any binlog player
		if newTablet.Type == topo.TYPE_MASTER {
			binlogPlayerMap.RefreshMap(newTablet)
		} else {
			binlogPlayerMap.StopAllPlayers()
		}
	})

	mysqld := mysqlctl.NewMysqld(mycnf, dbcfgs.Dba, dbcfgs.Repl)
	if err := agent.Start(bindAddr, secureAddr, mysqld.Addr()); err != nil {
		return err
	}

	// register the RPC services from the agent
	agent.RegisterQueryService(mysqld)

	return nil
}
Exemplo n.º 9
0
// InitAgent initializes the agent within vttablet.
func InitAgent(
	tabletAlias topo.TabletAlias,
	dbcfgs *dbconfigs.DBConfigs,
	mycnf *mysqlctl.Mycnf,
	port, securePort int,
	overridesFile string,
) (agent *tabletmanager.ActionAgent, err error) {
	schemaOverrides := loadSchemaOverrides(overridesFile)

	topoServer := topo.GetServer()
	mysqld := mysqlctl.NewMysqld(mycnf, &dbcfgs.Dba, &dbcfgs.Repl)

	statsType := stats.NewString("TabletType")
	statsKeyspace := stats.NewString("TabletKeyspace")
	statsShard := stats.NewString("TabletShard")
	statsKeyRangeStart := stats.NewString("TabletKeyRangeStart")
	statsKeyRangeEnd := stats.NewString("TabletKeyRangeEnd")

	agent, err = tabletmanager.NewActionAgent(topoServer, tabletAlias, mysqld)
	if err != nil {
		return nil, err
	}

	// Start the binlog player services, not playing at start.
	agent.BinlogPlayerMap = tabletmanager.NewBinlogPlayerMap(topoServer, &dbcfgs.App.ConnectionParams, mysqld)
	tabletmanager.RegisterBinlogPlayerMap(agent.BinlogPlayerMap)

	// Action agent listens to changes in zookeeper and makes
	// modifications to this tablet.
	agent.AddChangeCallback(func(oldTablet, newTablet topo.Tablet) {
		allowQuery := true
		var shardInfo *topo.ShardInfo
		var keyspaceInfo *topo.KeyspaceInfo
		if newTablet.Type == topo.TYPE_MASTER {
			// read the shard to get SourceShards
			shardInfo, err = topoServer.GetShard(newTablet.Keyspace, newTablet.Shard)
			if err != nil {
				log.Errorf("Cannot read shard for this tablet %v: %v", newTablet.Alias, err)
			} else {
				allowQuery = len(shardInfo.SourceShards) == 0
			}

			// read the keyspace to get ShardingColumnType
			keyspaceInfo, err = topoServer.GetKeyspace(newTablet.Keyspace)
			switch err {
			case nil:
				// continue
			case topo.ErrNoNode:
				// backward compatible mode
				keyspaceInfo = topo.NewKeyspaceInfo(newTablet.Keyspace, &topo.Keyspace{})
			default:
				log.Errorf("Cannot read keyspace for this tablet %v: %v", newTablet.Alias, err)
				keyspaceInfo = nil
			}
		}

		if newTablet.IsRunningQueryService() && allowQuery {
			if dbcfgs.App.DbName == "" {
				dbcfgs.App.DbName = newTablet.DbName()
			}
			dbcfgs.App.Keyspace = newTablet.Keyspace
			dbcfgs.App.Shard = newTablet.Shard
			if newTablet.Type != topo.TYPE_MASTER {
				dbcfgs.App.EnableInvalidator = true
			} else {
				dbcfgs.App.EnableInvalidator = false
			}
			// Transitioning from replica to master, first disconnect
			// existing connections. "false" indicateds that clients must
			// re-resolve their endpoint before reconnecting.
			if newTablet.Type == topo.TYPE_MASTER && oldTablet.Type != topo.TYPE_MASTER {
				ts.DisallowQueries()
			}
			qrs := ts.LoadCustomRules()
			if newTablet.KeyRange.IsPartial() {
				qr := ts.NewQueryRule("enforce keyspace_id range", "keyspace_id_not_in_range", ts.QR_FAIL_QUERY)
				qr.AddPlanCond(sqlparser.PLAN_INSERT_PK)
				err = qr.AddBindVarCond("keyspace_id", true, true, ts.QR_NOTIN, newTablet.KeyRange)
				if err != nil {
					log.Warningf("Unable to add keyspace rule: %v", err)
				} else {
					qrs.Add(qr)
				}
			}
			ts.AllowQueries(&dbcfgs.App, schemaOverrides, qrs, mysqld)
			// Disable before enabling to force existing streams to stop.
			binlog.DisableUpdateStreamService()
			binlog.EnableUpdateStreamService(dbcfgs)
		} else {
			ts.DisallowQueries()
			binlog.DisableUpdateStreamService()
		}

		statsType.Set(string(newTablet.Type))
		statsKeyspace.Set(newTablet.Keyspace)
		statsShard.Set(newTablet.Shard)
		statsKeyRangeStart.Set(string(newTablet.KeyRange.Start.Hex()))
		statsKeyRangeEnd.Set(string(newTablet.KeyRange.End.Hex()))

		// See if we need to start or stop any binlog player
		if newTablet.Type == topo.TYPE_MASTER {
			agent.BinlogPlayerMap.RefreshMap(newTablet, keyspaceInfo, shardInfo)
		} else {
			agent.BinlogPlayerMap.StopAllPlayersAndReset()
		}
	})

	if err := agent.Start(mysqld.Port(), port, securePort); err != nil {
		return nil, err
	}

	// register the RPC services from the agent
	agent.RegisterQueryService()

	return agent, nil
}
Exemplo n.º 10
0
func main() {
	flag.Parse()
	if err := servenv.Init("vtocc"); err != nil {
		relog.Fatal("Error in servenv.Init: %v", err)
	}
	if *queryLog != "" {
		if f, err := os.OpenFile(*queryLog, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0644); err == nil {
			ts.QueryLogger = relog.New(f, "", relog.DEBUG)
		} else {
			relog.Fatal("Error opening file %v: %v", *queryLog, err)
		}
	}
	ts.SqlQueryLogger.ServeLogs("/debug/querylog")
	ts.TxLogger.ServeLogs("/debug/txlog")
	unmarshalFile(*configFile, &config)
	data, _ := json.MarshalIndent(config, "", "  ")
	relog.Info("config: %s\n", data)

	unmarshalFile(*dbConfigFile, &dbconfig)
	relog.Info("dbconfig: %s\n", dbconfig)

	unmarshalFile(*overridesFile, &schemaOverrides)
	data, _ = json.MarshalIndent(schemaOverrides, "", "  ")
	relog.Info("schemaOverrides: %s\n", data)

	ts.RegisterQueryService(config)
	qrs := loadCustomRules()
	ts.AllowQueries(dbconfig, schemaOverrides, qrs)

	rpc.HandleHTTP()

	// NOTE(szopa): Changing credentials requires a server
	// restart.
	if *authConfig != "" {
		if err := auth.LoadCredentials(*authConfig); err != nil {
			relog.Error("could not load authentication credentials, not starting rpc servers: %v", err)
		}
		serveAuthRPC()
	}
	serveRPC()

	relog.Info("started vtocc %v", *port)

	// we delegate out startup to the micromanagement server so these actions
	// will occur after we have obtained our socket.
	usefulLameDuckPeriod := float64(config.QueryTimeout + 1)
	if usefulLameDuckPeriod > *lameDuckPeriod {
		*lameDuckPeriod = usefulLameDuckPeriod
		relog.Info("readjusted -lame-duck-period to %f", *lameDuckPeriod)
	}
	umgmt.SetLameDuckPeriod(float32(*lameDuckPeriod))
	umgmt.SetRebindDelay(float32(*rebindDelay))
	umgmt.AddStartupCallback(func() {
		umgmt.StartHttpServer(fmt.Sprintf(":%v", *port))
	})
	umgmt.AddStartupCallback(func() {
		c := make(chan os.Signal, 1)
		signal.Notify(c, syscall.SIGTERM)
		go func() {
			for sig := range c {
				umgmt.SigTermHandler(sig)
			}
		}()
	})
	umgmt.AddCloseCallback(func() {
		ts.DisallowQueries(true)
	})

	umgmtSocket := fmt.Sprintf("/tmp/vtocc-%08x-umgmt.sock", *port)
	if umgmtErr := umgmt.ListenAndServe(umgmtSocket); umgmtErr != nil {
		relog.Error("umgmt.ListenAndServe err: %v", umgmtErr)
	}
	relog.Info("done")
}
Exemplo n.º 11
0
func initAgent(tabletAlias topo.TabletAlias, dbcfgs dbconfigs.DBConfigs, mycnf *mysqlctl.Mycnf, dbConfigsFile, dbCredentialsFile string) error {
	topoServer := topo.GetServer()
	umgmt.AddCloseCallback(func() {
		topo.CloseServers()
	})

	bindAddr := fmt.Sprintf(":%v", *port)
	secureAddr := ""
	if *securePort != 0 {
		secureAddr = fmt.Sprintf(":%v", *securePort)
	}

	// Action agent listens to changes in zookeeper and makes
	// modifications to this tablet.
	agent, err := tm.NewActionAgent(topoServer, tabletAlias, *mycnfFile, dbConfigsFile, dbCredentialsFile)
	if err != nil {
		return err
	}
	agent.AddChangeCallback(func(oldTablet, newTablet topo.Tablet) {
		if newTablet.IsServingType() {
			if dbcfgs.App.Dbname == "" {
				dbcfgs.App.Dbname = newTablet.DbName()
			}
			dbcfgs.App.KeyRange = newTablet.KeyRange
			dbcfgs.App.Keyspace = newTablet.Keyspace
			dbcfgs.App.Shard = newTablet.Shard
			// Transitioning from replica to master, first disconnect
			// existing connections. "false" indicateds that clients must
			// re-resolve their endpoint before reconnecting.
			if newTablet.Type == topo.TYPE_MASTER && oldTablet.Type != topo.TYPE_MASTER {
				ts.DisallowQueries(false)
			}
			qrs := loadCustomRules()
			if dbcfgs.App.KeyRange.IsPartial() {
				qr := ts.NewQueryRule("enforce keyspace_id range", "keyspace_id_not_in_range", ts.QR_FAIL_QUERY)
				qr.AddPlanCond(sqlparser.PLAN_INSERT_PK)
				err = qr.AddBindVarCond("keyspace_id", true, true, ts.QR_NOTIN, dbcfgs.App.KeyRange)
				if err != nil {
					relog.Warning("Unable to add keyspace rule: %v", err)
				} else {
					qrs.Add(qr)
				}
			}
			ts.AllowQueries(dbcfgs.App, schemaOverrides, qrs)
			mysqlctl.EnableUpdateStreamService(string(newTablet.Type), dbcfgs)
			if newTablet.Type != topo.TYPE_MASTER {
				ts.StartRowCacheInvalidation()
			}
		} else {
			ts.DisallowQueries(false)
			mysqlctl.DisableUpdateStreamService()
			if newTablet.Type != topo.TYPE_MASTER {
				ts.StopRowCacheInvalidation()
			}
		}
	})

	mysqld := mysqlctl.NewMysqld(mycnf, dbcfgs.Dba, dbcfgs.Repl)
	if err := agent.Start(bindAddr, secureAddr, mysqld.Addr()); err != nil {
		return err
	}
	umgmt.AddCloseCallback(func() {
		agent.Stop()
	})

	// register the RPC services from the agent
	agent.RegisterQueryService(mysqld)

	return nil
}
Exemplo n.º 12
0
// InitAgent initializes the agent within vttablet.
func InitAgent(
	tabletAlias topo.TabletAlias,
	dbcfgs *dbconfigs.DBConfigs,
	mycnf *mysqlctl.Mycnf,
	port, securePort int,
	overridesFile string,
) (agent *tabletmanager.ActionAgent, err error) {
	schemaOverrides := loadSchemaOverrides(overridesFile)

	topoServer := topo.GetServer()
	mysqld := mysqlctl.NewMysqld(mycnf, &dbcfgs.Dba, &dbcfgs.Repl)

	statsType := stats.NewString("TabletType")
	statsKeyspace := stats.NewString("TabletKeyspace")
	statsShard := stats.NewString("TabletShard")
	statsKeyRangeStart := stats.NewString("TabletKeyRangeStart")
	statsKeyRangeEnd := stats.NewString("TabletKeyRangeEnd")

	agent, err = tabletmanager.NewActionAgent(topoServer, tabletAlias, mysqld)
	if err != nil {
		return nil, err
	}

	// Start the binlog player services, not playing at start.
	agent.BinlogPlayerMap = tabletmanager.NewBinlogPlayerMap(topoServer, &dbcfgs.App.ConnectionParams, mysqld)
	tabletmanager.RegisterBinlogPlayerMap(agent.BinlogPlayerMap)

	// Action agent listens to changes in zookeeper and makes
	// modifications to this tablet.
	agent.AddChangeCallback(func(oldTablet, newTablet topo.Tablet) {
		allowQuery := true
		var shardInfo *topo.ShardInfo
		var keyspaceInfo *topo.KeyspaceInfo
		if newTablet.Type == topo.TYPE_MASTER {
			// read the shard to get SourceShards
			shardInfo, err = topoServer.GetShard(newTablet.Keyspace, newTablet.Shard)
			if err != nil {
				log.Errorf("Cannot read shard for this tablet %v: %v", newTablet.Alias, err)
			} else {
				allowQuery = len(shardInfo.SourceShards) == 0
			}

			// read the keyspace to get ShardingColumnType
			keyspaceInfo, err = topoServer.GetKeyspace(newTablet.Keyspace)
			switch err {
			case nil:
				// continue
			case topo.ErrNoNode:
				// backward compatible mode
				keyspaceInfo = topo.NewKeyspaceInfo(newTablet.Keyspace, &topo.Keyspace{})
			default:
				log.Errorf("Cannot read keyspace for this tablet %v: %v", newTablet.Alias, err)
				keyspaceInfo = nil
			}
		}

		if newTablet.IsRunningQueryService() && allowQuery {
			if dbcfgs.App.DbName == "" {
				dbcfgs.App.DbName = newTablet.DbName()
			}
			dbcfgs.App.Keyspace = newTablet.Keyspace
			dbcfgs.App.Shard = newTablet.Shard
			if newTablet.Type != topo.TYPE_MASTER {
				dbcfgs.App.EnableInvalidator = true
			} else {
				dbcfgs.App.EnableInvalidator = false
			}

			// There are a few transitions when we're
			// going to need to restart the query service:
			// - transitioning from replica to master, so clients
			//   that were already connected don't keep on using
			//   the master as replica or rdonly.
			// - having different parameters for the query
			//   service. It needs to stop and restart with the
			//   new parameters. That includes:
			//   - changing KeyRange
			//   - changing the BlacklistedTables list
			if (newTablet.Type == topo.TYPE_MASTER &&
				oldTablet.Type != topo.TYPE_MASTER) ||
				(newTablet.KeyRange != oldTablet.KeyRange) ||
				!reflect.DeepEqual(newTablet.BlacklistedTables, oldTablet.BlacklistedTables) {
				ts.DisallowQueries()
			}
			qrs := ts.LoadCustomRules()
			if newTablet.KeyRange.IsPartial() {
				qr := ts.NewQueryRule("enforce keyspace_id range", "keyspace_id_not_in_range", ts.QR_FAIL_QUERY)
				qr.AddPlanCond(sqlparser.PLAN_INSERT_PK)
				err = qr.AddBindVarCond("keyspace_id", true, true, ts.QR_NOTIN, newTablet.KeyRange)
				if err != nil {
					log.Warningf("Unable to add keyspace rule: %v", err)
				} else {
					qrs.Add(qr)
				}
			}
			if len(newTablet.BlacklistedTables) > 0 {
				log.Infof("Blacklisting tables %v", strings.Join(newTablet.BlacklistedTables, ", "))
				qr := ts.NewQueryRule("enforce blacklisted tables", "blacklisted_table", ts.QR_FAIL_QUERY)
				for _, t := range newTablet.BlacklistedTables {
					qr.AddTableCond(t)
				}
				qrs.Add(qr)
			}
			ts.AllowQueries(&dbcfgs.App, schemaOverrides, qrs, mysqld)
			// Disable before enabling to force existing streams to stop.
			binlog.DisableUpdateStreamService()
			binlog.EnableUpdateStreamService(dbcfgs)
		} else {
			ts.DisallowQueries()
			binlog.DisableUpdateStreamService()
		}

		statsType.Set(string(newTablet.Type))
		statsKeyspace.Set(newTablet.Keyspace)
		statsShard.Set(newTablet.Shard)
		statsKeyRangeStart.Set(string(newTablet.KeyRange.Start.Hex()))
		statsKeyRangeEnd.Set(string(newTablet.KeyRange.End.Hex()))

		// See if we need to start or stop any binlog player
		if newTablet.Type == topo.TYPE_MASTER {
			agent.BinlogPlayerMap.RefreshMap(newTablet, keyspaceInfo, shardInfo)
		} else {
			agent.BinlogPlayerMap.StopAllPlayersAndReset()
		}
	})

	if err := agent.Start(mysqld.Port(), port, securePort); err != nil {
		return nil, err
	}

	// register the RPC services from the agent
	agent.RegisterQueryService()

	// start health check if needed
	initHeathCheck(agent)

	return agent, nil
}