// ExecuteVtworkerCommand is part of the vtworkerdatapb.VtworkerServer interface
func (s *VtworkerServer) ExecuteVtworkerCommand(args *vtworkerdatapb.ExecuteVtworkerCommandRequest, stream vtworkerservicepb.Vtworker_ExecuteVtworkerCommandServer) (err error) {
	// Please note that this panic handler catches only panics occuring in the code below.
	// The actual execution of the vtworker command takes place in a new go routine
	// (started in Instance.setAndStartWorker()) which has its own panic handler.
	defer servenv.HandlePanic("vtworker", &err)

	// Stream everything back what the Wrangler is logging.
	logstream := logutil.NewCallbackLogger(func(e *logutilpb.Event) {
		// If the client disconnects, we will just fail
		// to send the log events, but won't interrupt
		// the command.
		stream.Send(&vtworkerdatapb.ExecuteVtworkerCommandResponse{
			Event: e,
		})
	})
	// Let the Wrangler also log everything to the console (and thereby
	// effectively to a logfile) to make sure that any information or errors
	// is preserved in the logs in case the RPC or vtworker crashes.
	logger := logutil.NewTeeLogger(logstream, logutil.NewConsoleLogger())

	// create the wrangler
	wr := s.wi.CreateWrangler(logger)

	// execute the command
	worker, done, err := s.wi.RunCommand(args.Args, wr, false /*runFromCli*/)
	if err == nil && worker != nil && done != nil {
		err = s.wi.WaitForCommand(worker, done)
	}

	return err
}

func runCommand(args []string) {
	wrk := commandWorker(wr, args)
	done, err := setAndStartWorker(wrk, logutil.NewConsoleLogger())
	if err != nil {
		log.Fatalf("Cannot set worker: %v", err)
	}

	// a go routine displays the status every second
	go func() {
		timer := time.Tick(*commandDisplayInterval)
		for {
			select {
			case <-done:
				log.Infof("Command is done:")
				log.Info(wrk.StatusAsText())
				if wrk.Error() != nil {
					os.Exit(1)
				}
				os.Exit(0)
			case <-timer:
				log.Info(wrk.StatusAsText())
			}
		}
	}()
}

func (ar *ActionRepository) ApplyTabletAction(actionName string, tabletAlias topo.TabletAlias, r *http.Request) *ActionResult {
	result := &ActionResult{Name: actionName, Parameters: tabletAlias.String()}

	action, ok := ar.tabletActions[actionName]
	if !ok {
		result.error("Unknown tablet action")
		return result
	}

	// check the role
	if action.role != "" {
		if err := acl.CheckAccessHTTP(r, action.role); err != nil {
			result.error("Access denied")
			return result
		}
	}

	// run the action
	wr := wrangler.New(logutil.NewConsoleLogger(), ar.ts, wrangler.DefaultActionTimeout, actionnode.DefaultLockTimeout)
	output, err := action.method(wr, tabletAlias, r)
	if err != nil {
		result.error(err.Error())
		return result
	}
	result.Output = output
	return result
}

func TestSchemaManagerExecutorFail(t *testing.T) {
	sql := "create table test_table (pk int)"
	controller := newFakeController([]string{sql}, false, false, false)
	fakeTmc := newFakeTabletManagerClient()
	fakeTmc.AddSchemaChange(sql, &tabletmanagerdatapb.SchemaChangeResult{
		BeforeSchema: &tabletmanagerdatapb.SchemaDefinition{},
		AfterSchema: &tabletmanagerdatapb.SchemaDefinition{
			DatabaseSchema: "CREATE DATABASE `{{.DatabaseName}}` /*!40100 DEFAULT CHARACTER SET utf8 */",
			TableDefinitions: []*tabletmanagerdatapb.TableDefinition{
				{
					Name:   "test_table",
					Schema: sql,
					Type:   tmutils.TableBaseTable,
				},
			},
		},
	})

	fakeTmc.AddSchemaDefinition("vt_test_keyspace", &tabletmanagerdatapb.SchemaDefinition{})
	fakeTmc.EnableExecuteFetchAsDbaError = true
	wr := wrangler.New(logutil.NewConsoleLogger(), newFakeTopo(), fakeTmc)
	executor := NewTabletExecutor(wr, testWaitSlaveTimeout)

	ctx := context.Background()
	err := Run(ctx, controller, executor)

	if err == nil {
		t.Fatalf("schema change should fail")
	}
}

// TestEmergencyReparentShardMasterElectNotBest tries to emergency reparent
// to a host that is not the latest in replication position.
func TestEmergencyReparentShardMasterElectNotBest(t *testing.T) {
	ctx := context.Background()
	ts := zktopo.NewTestServer(t, []string{"cell1", "cell2"})
	wr := wrangler.New(logutil.NewConsoleLogger(), ts, tmclient.NewTabletManagerClient(), time.Second)

	// Create a master, a couple good slaves
	oldMaster := NewFakeTablet(t, wr, "cell1", 0, topo.TYPE_MASTER)
	newMaster := NewFakeTablet(t, wr, "cell1", 1, topo.TYPE_REPLICA)
	moreAdvancedSlave := NewFakeTablet(t, wr, "cell1", 2, topo.TYPE_REPLICA)

	// new master
	newMaster.FakeMysqlDaemon.Replicating = true
	newMaster.FakeMysqlDaemon.CurrentMasterPosition = myproto.ReplicationPosition{
		GTIDSet: myproto.MariadbGTID{
			Domain:   2,
			Server:   123,
			Sequence: 456,
		},
	}
	newMaster.FakeMysqlDaemon.ExpectedExecuteSuperQueryList = []string{
		"STOP SLAVE",
	}
	newMaster.StartActionLoop(t, wr)
	defer newMaster.StopActionLoop(t)

	// old master, will be scrapped
	oldMaster.StartActionLoop(t, wr)
	defer oldMaster.StopActionLoop(t)

	// more advanced slave
	moreAdvancedSlave.FakeMysqlDaemon.Replicating = true
	moreAdvancedSlave.FakeMysqlDaemon.CurrentMasterPosition = myproto.ReplicationPosition{
		GTIDSet: myproto.MariadbGTID{
			Domain:   2,
			Server:   123,
			Sequence: 457,
		},
	}
	moreAdvancedSlave.FakeMysqlDaemon.ExpectedExecuteSuperQueryList = []string{
		"STOP SLAVE",
	}
	moreAdvancedSlave.StartActionLoop(t, wr)
	defer moreAdvancedSlave.StopActionLoop(t)

	// run EmergencyReparentShard
	if err := wr.EmergencyReparentShard(ctx, newMaster.Tablet.Keyspace, newMaster.Tablet.Shard, newMaster.Tablet.Alias, 10*time.Second); err == nil || !strings.Contains(err.Error(), "is more advanced than master elect tablet") {
		t.Fatalf("EmergencyReparentShard returned the wrong error: %v", err)
	}

	// check what was run
	if err := newMaster.FakeMysqlDaemon.CheckSuperQueryList(); err != nil {
		t.Fatalf("newMaster.FakeMysqlDaemon.CheckSuperQueryList failed: %v", err)
	}
	if err := oldMaster.FakeMysqlDaemon.CheckSuperQueryList(); err != nil {
		t.Fatalf("oldMaster.FakeMysqlDaemon.CheckSuperQueryList failed: %v", err)
	}
	if err := moreAdvancedSlave.FakeMysqlDaemon.CheckSuperQueryList(); err != nil {
		t.Fatalf("moreAdvancedSlave.FakeMysqlDaemon.CheckSuperQueryList failed: %v", err)
	}
}

// ApplyShardAction applies the provided action to the shard.
func (ar *ActionRepository) ApplyShardAction(ctx context.Context, actionName, keyspace, shard string, r *http.Request) *ActionResult {
	// if the shard name contains a '-', we assume it's the
	// name for a ranged based shard, so we lower case it.
	if strings.Contains(shard, "-") {
		shard = strings.ToLower(shard)
	}
	result := &ActionResult{Name: actionName, Parameters: keyspace + "/" + shard}

	action, ok := ar.shardActions[actionName]
	if !ok {
		result.error("Unknown shard action")
		return result
	}

	ctx, cancel := context.WithTimeout(ctx, *actionTimeout)
	wr := wrangler.New(logutil.NewConsoleLogger(), ar.ts, tmclient.NewTabletManagerClient())
	output, err := action(ctx, wr, keyspace, shard, r)
	cancel()
	if err != nil {
		result.error(err.Error())
		return result
	}
	result.Output = output
	return result
}

// RestoreFromBackup deletes all local data and restores anew from the latest backup.
func (agent *ActionAgent) RestoreFromBackup(ctx context.Context, logger logutil.Logger) error {
	if err := agent.lock(ctx); err != nil {
		return err
	}
	defer agent.unlock()

	tablet, err := agent.TopoServer.GetTablet(ctx, agent.TabletAlias)
	if err != nil {
		return err
	}
	if tablet.Type == topodatapb.TabletType_MASTER {
		return fmt.Errorf("type MASTER cannot restore from backup, if you really need to do this, restart vttablet in replica mode")
	}

	// create the loggers: tee to console and source
	l := logutil.NewTeeLogger(logutil.NewConsoleLogger(), logger)

	// now we can run restore
	err = agent.restoreDataLocked(ctx, l, true /* deleteBeforeRestore */)

	// re-run health check to be sure to capture any replication delay
	agent.runHealthCheckLocked()

	return err
}

// ApplyTabletAction applies the provided action to the tablet.
func (ar *ActionRepository) ApplyTabletAction(ctx context.Context, actionName string, tabletAlias *topodatapb.TabletAlias, r *http.Request) *ActionResult {
	result := &ActionResult{
		Name:       actionName,
		Parameters: topoproto.TabletAliasString(tabletAlias),
	}

	action, ok := ar.tabletActions[actionName]
	if !ok {
		result.error("Unknown tablet action")
		return result
	}

	// check the role
	if action.role != "" {
		if err := acl.CheckAccessHTTP(r, action.role); err != nil {
			result.error("Access denied")
			return result
		}
	}

	// run the action
	ctx, cancel := context.WithTimeout(ctx, *actionTimeout)
	wr := wrangler.New(logutil.NewConsoleLogger(), ar.ts, tmclient.NewTabletManagerClient())
	output, err := action.method(ctx, wr, tabletAlias, r)
	cancel()
	if err != nil {
		result.error(err.Error())
		return result
	}
	result.Output = output
	return result
}

func TestTabletExternallyReparentedFailedOldMaster(t *testing.T) {
	tabletmanager.SetReparentFlags(time.Minute /* finalizeTimeout */)

	ctx := context.Background()
	ts := zktopo.NewTestServer(t, []string{"cell1", "cell2"})
	wr := wrangler.New(logutil.NewConsoleLogger(), ts, tmclient.NewTabletManagerClient(), time.Second)

	// Create an old master, a new master, and a good slave.
	oldMaster := NewFakeTablet(t, wr, "cell1", 0, topo.TYPE_MASTER)
	newMaster := NewFakeTablet(t, wr, "cell1", 1, topo.TYPE_REPLICA)
	goodSlave := NewFakeTablet(t, wr, "cell1", 2, topo.TYPE_REPLICA)

	// Reparent to a replica, and pretend the old master is not responding.

	// On the elected master, we will respond to
	// TabletActionSlaveWasPromoted
	newMaster.StartActionLoop(t, wr)
	defer newMaster.StopActionLoop(t)

	// On the old master, we will only get a
	// TabletActionSlaveWasRestarted call, let's just not
	// respond to it at all

	// On the good slave, we will respond to
	// TabletActionSlaveWasRestarted.
	goodSlave.StartActionLoop(t, wr)
	defer goodSlave.StopActionLoop(t)

	// The reparent should work as expected here
	t.Logf("TabletExternallyReparented(new master) expecting success")
	tmc := tmclient.NewTabletManagerClient()
	ti, err := ts.GetTablet(ctx, newMaster.Tablet.Alias)
	if err != nil {
		t.Fatalf("GetTablet failed: %v", err)
	}
	waitID := makeWaitID()
	if err := tmc.TabletExternallyReparented(context.Background(), ti, waitID); err != nil {
		t.Fatalf("TabletExternallyReparented(replica) failed: %v", err)
	}
	waitForExternalReparent(t, waitID)

	// Now double-check the serving graph is good.
	// Should only have one good replica left.
	addrs, _, err := ts.GetEndPoints(ctx, "cell1", "test_keyspace", "0", topo.TYPE_REPLICA)
	if err != nil {
		t.Fatalf("GetEndPoints failed at the end: %v", err)
	}
	if len(addrs.Entries) != 1 {
		t.Fatalf("GetEndPoints has too many entries: %v", addrs)
	}

	// check the old master was converted to spare
	tablet, err := ts.GetTablet(ctx, oldMaster.Tablet.Alias)
	if err != nil {
		t.Fatalf("GetTablet(%v) failed: %v", oldMaster.Tablet.Alias, err)
	}
	if tablet.Type != topo.TYPE_SPARE {
		t.Fatalf("old master should be spare but is: %v", tablet.Type)
	}
}

func main() {
	flag.Parse()
	args := flag.Args()

	installSignalHandlers()

	servenv.Init()
	defer servenv.Close()

	ts := topo.GetServer()
	defer topo.CloseServers()

	// the logger will be replaced when we start a job
	wr = wrangler.New(logutil.NewConsoleLogger(), ts, 30*time.Second, 30*time.Second)
	if len(args) == 0 {
		// interactive mode, initialize the web UI to chose a command
		initInteractiveMode()
	} else {
		// single command mode, just runs it
		runCommand(args)
	}
	initStatusHandling()

	servenv.RunDefault()
}

func main() {
	flag.Parse()

	ctx, cancel := context.WithTimeout(context.Background(), *actionTimeout)
	defer cancel()
	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, syscall.SIGTERM, syscall.SIGINT)
	go func() {
		s := <-sigChan
		log.Errorf("Trying to cancel current command after receiving signal: %v", s)
		cancel()
	}()

	logger := logutil.NewConsoleLogger()

	err := vtworkerclient.RunCommandAndWait(
		ctx, *server, flag.Args(),
		func(e *logutilpb.Event) {
			logutil.LogEvent(logger, e)
		})
	if err != nil {
		log.Error(err)
		os.Exit(1)
	}
}

// TestNewRestartableResultReader tests the correct error handling e.g.
// if the connection to a tablet fails due to a canceled context.
func TestNewRestartableResultReader(t *testing.T) {
	wantErr := errors.New("restartable_result_reader_test.go: context canceled")

	tabletconn.RegisterDialer("fake_dialer", func(tablet *topodatapb.Tablet, timeout time.Duration) (tabletconn.TabletConn, error) {
		return nil, wantErr
	})
	protocol := flag.CommandLine.Lookup("tablet_protocol").Value.String()
	flag.Set("tablet_protocol", "fake_dialer")
	// Restore the previous flag value after the test.
	defer flag.Set("tablet_protocol", protocol)

	// Create dependencies e.g. a "singleTabletProvider" instance.
	ts := zktestserver.New(t, []string{"cell1"})
	wr := wrangler.New(logutil.NewConsoleLogger(), ts, tmclient.NewTabletManagerClient())
	alias := &topodatapb.TabletAlias{
		Cell: "cell1",
		Uid:  1,
	}
	tablet := &topodatapb.Tablet{
		Keyspace: "ks1",
		Shard:    "-80",
		Alias:    alias,
	}
	ctx := context.Background()
	if err := ts.CreateTablet(ctx, tablet); err != nil {
		t.Fatalf("CreateTablet failed: %v", err)
	}
	tp := newSingleTabletProvider(ctx, ts, alias)

	_, err := NewRestartableResultReader(ctx, wr.Logger(), tp, nil /* td */, chunk{}, false)
	if err == nil || !strings.Contains(err.Error(), wantErr.Error()) {
		t.Fatalf("NewRestartableResultReader() should have failed because the context is canceled: %v", err)
	}
}

// ExecuteVtctlCommand is part of the pb.VtctlServer interface
func (s *VtctlServer) ExecuteVtctlCommand(args *pb.ExecuteVtctlCommandRequest, stream pbs.Vtctl_ExecuteVtctlCommandServer) (err error) {
	defer servenv.HandlePanic("vtctl", &err)

	// create a logger, send the result back to the caller
	logstream := logutil.NewChannelLogger(10)
	logger := logutil.NewTeeLogger(logstream, logutil.NewConsoleLogger())

	// send logs to the caller
	wg := sync.WaitGroup{}
	wg.Add(1)
	go func() {
		for e := range logstream {
			// Note we don't interrupt the loop here, as
			// we still need to flush and finish the
			// command, even if the channel to the client
			// has been broken. We'll just keep trying.
			stream.Send(&pb.ExecuteVtctlCommandResponse{
				Event: logutil.LoggerEventToProto(&e),
			})
		}
		wg.Done()
	}()

	// create the wrangler
	wr := wrangler.New(logger, s.ts, tmclient.NewTabletManagerClient(), time.Duration(args.LockTimeout))

	// execute the command
	err = vtctl.RunCommand(stream.Context(), wr, args.Args)

	// close the log channel, and wait for them all to be sent
	close(logstream)
	wg.Wait()

	return err
}

// MultiSnapshot takes a multi-part snapshot
// Should be called under RpcWrapLockAction.
func (agent *ActionAgent) MultiSnapshot(args *actionnode.MultiSnapshotArgs, logger logutil.Logger) (*actionnode.MultiSnapshotReply, error) {
	tablet, err := agent.TopoServer.GetTablet(agent.TabletAlias)
	if err != nil {
		return nil, err
	}
	ki, err := agent.TopoServer.GetKeyspace(tablet.Keyspace)
	if err != nil {
		return nil, err
	}

	if tablet.Type != topo.TYPE_BACKUP {
		return nil, fmt.Errorf("expected backup type, not %v", tablet.Type)
	}

	// create the loggers: tee to console and source
	l := logutil.NewTeeLogger(logutil.NewConsoleLogger(), logger)

	filenames, err := agent.Mysqld.CreateMultiSnapshot(l, args.KeyRanges, tablet.DbName(), ki.ShardingColumnName, ki.ShardingColumnType, tablet.Addr(), false, args.Concurrency, args.Tables, args.ExcludeTables, args.SkipSlaveRestart, args.MaximumFilesize, agent.hookExtraEnv())
	if err != nil {
		return nil, err
	}

	sr := &actionnode.MultiSnapshotReply{ManifestPaths: filenames}
	if tablet.Parent.Uid == topo.NO_TABLET {
		// If this is a master, this will be the new parent.
		// FIXME(msolomon) this doens't work in hierarchical replication.
		sr.ParentAlias = tablet.Alias
	} else {
		sr.ParentAlias = tablet.Parent
	}
	return sr, nil
}

// ExecuteVtctlCommand is the server side method that will execute the query,
// and stream the results.
func (s *VtctlServer) ExecuteVtctlCommand(context context.Context, query *gorpcproto.ExecuteVtctlCommandArgs, sendReply func(interface{}) error) error {
	// create a logger, send the result back to the caller
	logstream := logutil.NewChannelLogger(10)
	logger := logutil.NewTeeLogger(logstream, logutil.NewConsoleLogger())

	// send logs to the caller
	wg := sync.WaitGroup{}
	wg.Add(1)
	go func() {
		for e := range logstream {
			// Note we don't interrupt the loop here, as
			// we still need to flush and finish the
			// command, even if the channel to the client
			// has been broken. We'll just keep trying.
			sendReply(&e)
		}
		wg.Done()
	}()

	// create the wrangler
	wr := wrangler.New(logger, s.ts, query.ActionTimeout, query.LockTimeout)

	// execute the command
	err := vtctl.RunCommand(wr, query.Args)

	// close the log channel, and wait for them all to be sent
	close(logstream)
	wg.Wait()

	return err
}

// TestInitMasterShardChecks makes sure the safety checks work
func TestInitMasterShardChecks(t *testing.T) {
	ctx := context.Background()
	db := fakesqldb.Register()
	ts := zktestserver.New(t, []string{"cell1", "cell2"})
	wr := wrangler.New(logutil.NewConsoleLogger(), ts, tmclient.NewTabletManagerClient())

	master := NewFakeTablet(t, wr, "cell1", 0, topodatapb.TabletType_MASTER, db)

	// InitShardMaster with an unknown tablet
	if err := wr.InitShardMaster(ctx, master.Tablet.Keyspace, master.Tablet.Shard, &topodatapb.TabletAlias{
		Cell: master.Tablet.Alias.Cell,
		Uid:  master.Tablet.Alias.Uid + 1,
	}, false /*force*/, 10*time.Second); err == nil || !strings.Contains(err.Error(), "is not in the shard") {
		t.Errorf("InitShardMaster with unknown alias returned wrong error: %v", err)
	}

	// InitShardMaster with two masters in the shard, no force flag
	// (master2 needs to run InitTablet with -force, as it is the second
	// master in the same shard)
	master2 := NewFakeTablet(t, wr, "cell1", 1, topodatapb.TabletType_MASTER, db, ForceInitTablet())
	if err := wr.InitShardMaster(ctx, master2.Tablet.Keyspace, master2.Tablet.Shard, master2.Tablet.Alias, false /*force*/, 10*time.Second); err == nil || !strings.Contains(err.Error(), "is not the only master in the shard") {
		t.Errorf("InitShardMaster with two masters returned wrong error: %v", err)
	}

	// InitShardMaster where the new master fails (use force flag
	// as we have 2 masters). We force the failure by making the
	// SQL commands executed on the master unexpected by the test fixture
	master.StartActionLoop(t, wr)
	defer master.StopActionLoop(t)
	master2.StartActionLoop(t, wr)
	defer master2.StopActionLoop(t)
	if err := wr.InitShardMaster(ctx, master.Tablet.Keyspace, master.Tablet.Shard, master.Tablet.Alias, true /*force*/, 10*time.Second); err == nil || !strings.Contains(err.Error(), "unexpected extra query") {
		t.Errorf("InitShardMaster with new master failing in new master InitMaster returned wrong error: %v", err)
	}
}

func TestShardExternallyReparentedFailedOldMaster(t *testing.T) {
	ts := zktopo.NewTestServer(t, []string{"cell1", "cell2"})
	wr := wrangler.New(logutil.NewConsoleLogger(), ts, time.Minute, time.Second)

	// Create an old master, a new master, two good slaves
	oldMaster := NewFakeTablet(t, wr, "cell1", 0, topo.TYPE_MASTER)
	newMaster := NewFakeTablet(t, wr, "cell1", 1, topo.TYPE_REPLICA,
		TabletParent(oldMaster.Tablet.Alias))
	goodSlave := NewFakeTablet(t, wr, "cell1", 2, topo.TYPE_REPLICA,
		TabletParent(oldMaster.Tablet.Alias))

	// Reparent to a replica, and pretend the old master is not responding

	// On the elected master, we will respond to
	// TABLET_ACTION_SLAVE_WAS_PROMOTED
	newMaster.FakeMysqlDaemon.MasterAddr = ""
	newMaster.StartActionLoop(t, wr)
	defer newMaster.StopActionLoop(t)

	// On the old master, we will only get a
	// TABLET_ACTION_SLAVE_WAS_RESTARTED call, let's just not
	// respond to it at all

	// On the good slave, we will respond to
	// TABLET_ACTION_SLAVE_WAS_RESTARTED.
	goodSlave.FakeMysqlDaemon.MasterAddr = newMaster.Tablet.MysqlIpAddr()
	goodSlave.StartActionLoop(t, wr)
	defer goodSlave.StopActionLoop(t)

	// The reparent should work as expected here
	t.Logf("ShardExternallyReparented(new master) expecting success")
	if err := wr.ShardExternallyReparented("test_keyspace", "0", newMaster.Tablet.Alias); err != nil {
		t.Fatalf("ShardExternallyReparented(replica) failed: %v", err)
	}

	// Now double-check the serving graph is good.
	// Should only have one good replica left.
	addrs, err := ts.GetEndPoints("cell1", "test_keyspace", "0", topo.TYPE_REPLICA)
	if err != nil {
		t.Fatalf("GetEndPoints failed at the end: %v", err)
	}
	if len(addrs.Entries) != 1 {
		t.Fatalf("GetEndPoints has too many entries: %v", addrs)
	}

	// check the old master was converted to spare
	tablet, err := ts.GetTablet(oldMaster.Tablet.Alias)
	if err != nil {
		t.Fatalf("GetTablet(%v) failed: %v", oldMaster.Tablet.Alias, err)
	}
	if tablet.Type != topo.TYPE_SPARE {
		t.Fatalf("old master should be spare but is: %v", tablet.Type)
	}
	if tablet.Parent != newMaster.Tablet.Alias {
		t.Fatalf("old master has the wrong master, got %v expected %v", tablet.Parent, newMaster.Tablet.Alias)
	}
}

func init() {
	logger := logutil.NewConsoleLogger()
	flag.CommandLine.SetOutput(logutil.NewLoggerWriter(logger))
	flag.Usage = func() {
		logger.Printf("Usage: %s [global parameters] command [command parameters]\n", os.Args[0])
		logger.Printf("\nThe global optional parameters are:\n")
		flag.PrintDefaults()
		logger.Printf("\nThe commands are listed below, sorted by group. Use '%s <command> -h' for more help.\n\n", os.Args[0])
		vtctl.PrintAllCommands(logger)
	}
}

func TestTabletExecutorOpenWithEmptyMasterAlias(t *testing.T) {
	ft := newFakeTopo()
	ft.Impl.(*fakeTopo).WithEmptyMasterAlias = true
	wr := wrangler.New(logutil.NewConsoleLogger(), ft, newFakeTabletManagerClient())
	executor := NewTabletExecutor(wr, testWaitSlaveTimeout)
	ctx := context.Background()

	if err := executor.Open(ctx, "test_keyspace"); err == nil {
		t.Fatalf("executor.Open() = nil, want error")
	}
	executor.Close()
}

// Backup takes a db backup and sends it to the BackupStorage
func (agent *ActionAgent) Backup(ctx context.Context, concurrency int, logger logutil.Logger) error {
	if err := agent.lock(ctx); err != nil {
		return err
	}
	defer agent.unlock()

	// update our type to BACKUP
	tablet, err := agent.TopoServer.GetTablet(ctx, agent.TabletAlias)
	if err != nil {
		return err
	}
	if tablet.Type == topodatapb.TabletType_MASTER {
		return fmt.Errorf("type MASTER cannot take backup, if you really need to do this, restart vttablet in replica mode")
	}
	originalType := tablet.Type
	if _, err := topotools.ChangeType(ctx, agent.TopoServer, tablet.Alias, topodatapb.TabletType_BACKUP); err != nil {
		return err
	}

	// let's update our internal state (stop query service and other things)
	if err := agent.refreshTablet(ctx, "before backup"); err != nil {
		return err
	}

	// create the loggers: tee to console and source
	l := logutil.NewTeeLogger(logutil.NewConsoleLogger(), logger)

	// now we can run the backup
	dir := fmt.Sprintf("%v/%v", tablet.Keyspace, tablet.Shard)
	name := fmt.Sprintf("%v.%v", time.Now().UTC().Format("2006-01-02.150405"), topoproto.TabletAliasString(tablet.Alias))
	returnErr := mysqlctl.Backup(ctx, agent.MysqlDaemon, l, dir, name, concurrency, agent.hookExtraEnv())

	// change our type back to the original value
	_, err = topotools.ChangeType(ctx, agent.TopoServer, tablet.Alias, originalType)
	if err != nil {
		// failure in changing the topology type is probably worse,
		// so returning that (we logged the snapshot error anyway)
		if returnErr != nil {
			l.Errorf("mysql backup command returned error: %v", returnErr)
		}
		returnErr = err
	}

	// let's update our internal state (start query service and other things)
	if err := agent.refreshTablet(ctx, "after backup"); err != nil {
		return err
	}

	// and re-run health check to be sure to capture any replication delay
	agent.runHealthCheckLocked()

	return returnErr
}