// GetTabletsByCell implements topo.Server.
func (s *Server) GetTabletsByCell(ctx context.Context, cellName string) ([]topo.TabletAlias, error) {
	cell, err := s.getCell(cellName)
	if err != nil {
		return nil, err
	}

	resp, err := cell.Get(tabletsDirPath, false /* sort */, false /* recursive */)
	if err != nil {
		return nil, convertError(err)
	}

	nodes, err := getNodeNames(resp)
	if err != nil {
		return nil, err
	}

	tablets := make([]topo.TabletAlias, 0, len(nodes))
	for _, node := range nodes {
		tabletAlias, err := topo.ParseTabletAliasString(node)
		if err != nil {
			return nil, err
		}
		tablets = append(tablets, tabletAlias)
	}
	return tablets, nil
}

// actionPathToTabletAlias parses an actionPath back
// zkActionPath is /zk/<cell>/vt/tablets/<uid>/action/<number>
func actionPathToTabletAlias(actionPath string) (topo.TabletAlias, error) {
	pathParts := strings.Split(actionPath, "/")
	if len(pathParts) != 8 || pathParts[0] != "" || pathParts[1] != "zk" || pathParts[3] != "vt" || pathParts[4] != "tablets" || pathParts[6] != "action" {
		return topo.TabletAlias{}, fmt.Errorf("invalid action path: %v", actionPath)
	}
	return topo.ParseTabletAliasString(pathParts[2] + "-" + pathParts[5])
}

// handleExplorerRedirect returns the redirect target URL.
func handleExplorerRedirect(r *http.Request) (string, error) {
	keyspace := r.FormValue("keyspace")
	shard := r.FormValue("shard")
	cell := r.FormValue("cell")

	switch r.FormValue("type") {
	case "keyspace":
		if keyspace == "" {
			return "", errors.New("keyspace is required for this redirect")
		}
		return explorer.GetKeyspacePath(keyspace), nil
	case "shard":
		if keyspace == "" || shard == "" {
			return "", errors.New("keyspace and shard are required for this redirect")
		}
		return explorer.GetShardPath(keyspace, shard), nil
	case "srv_keyspace":
		if keyspace == "" || cell == "" {
			return "", errors.New("keyspace and cell are required for this redirect")
		}
		return explorer.GetSrvKeyspacePath(cell, keyspace), nil
	case "srv_shard":
		if keyspace == "" || shard == "" || cell == "" {
			return "", errors.New("keyspace, shard, and cell are required for this redirect")
		}
		return explorer.GetSrvShardPath(cell, keyspace, shard), nil
	case "srv_type":
		tabletType := r.FormValue("tablet_type")
		if keyspace == "" || shard == "" || cell == "" || tabletType == "" {
			return "", errors.New("keyspace, shard, cell, and tablet_type are required for this redirect")
		}
		tt, err := topo.ParseTabletType(tabletType)
		if err != nil {
			return "", fmt.Errorf("cannot parse tablet type %v: %v", tabletType, err)
		}
		return explorer.GetSrvTypePath(cell, keyspace, shard, tt), nil
	case "tablet":
		alias := r.FormValue("alias")
		if alias == "" {
			return "", errors.New("alias is required for this redirect")
		}
		tabletAlias, err := topo.ParseTabletAliasString(alias)
		if err != nil {
			return "", fmt.Errorf("bad tablet alias %q: %v", alias, err)
		}
		return explorer.GetTabletPath(tabletAlias), nil
	case "replication":
		if keyspace == "" || shard == "" || cell == "" {
			return "", errors.New("keyspace, shard, and cell are required for this redirect")
		}
		return explorer.GetReplicationSlaves(cell, keyspace, shard), nil
	default:
		return "", errors.New("bad redirect type")
	}
}

// FIXME(alainjobart) remove after migration
func BackfillAlias(zkPath string, alias *topo.TabletAlias) error {
	if alias.IsZero() && zkPath != "" {
		zkPathParts := strings.Split(zkPath, "/")
		if len(zkPathParts) != 6 || zkPathParts[0] != "" || zkPathParts[1] != "zk" || zkPathParts[3] != "vt" || zkPathParts[4] != "tablets" {
			return fmt.Errorf("Invalid tablet path: %v", zkPath)
		}
		a, err := topo.ParseTabletAliasString(zkPathParts[2] + "-" + zkPathParts[5])
		if err != nil {
			return err
		}
		*alias = a
	}
	return nil
}

// tabletParamToTabletAlias takes either an old style ZK tablet path or a
// new style tablet alias as a string, and returns a TabletAlias.
func tabletParamToTabletAlias(param string) topo.TabletAlias {
	if param[0] == '/' {
		// old zookeeper path, convert to new-style string tablet alias
		zkPathParts := strings.Split(param, "/")
		if len(zkPathParts) != 6 || zkPathParts[0] != "" || zkPathParts[1] != "zk" || zkPathParts[3] != "vt" || zkPathParts[4] != "tablets" {
			log.Fatalf("Invalid tablet path: %v", param)
		}
		param = zkPathParts[2] + "-" + zkPathParts[5]
	}
	result, err := topo.ParseTabletAliasString(param)
	if err != nil {
		log.Fatalf("Invalid tablet alias %v: %v", param, err)
	}
	return result
}

func commandVtTabletStreamHealth(ctx context.Context, wr *wrangler.Wrangler, subFlags *flag.FlagSet, args []string) error {
	count := subFlags.Int("count", 1, "number of responses to wait for")
	connectTimeout := subFlags.Duration("connect_timeout", 30*time.Second, "Connection timeout for vttablet client")
	if err := subFlags.Parse(args); err != nil {
		return err
	}
	if subFlags.NArg() != 1 {
		return fmt.Errorf("The <tablet alias> argument is required for the VtTabletStreamHealth command.")
	}
	tabletAlias, err := topo.ParseTabletAliasString(subFlags.Arg(0))
	if err != nil {
		return err
	}
	tabletInfo, err := wr.TopoServer().GetTablet(ctx, tabletAlias)
	if err != nil {
		return err
	}

	ep, err := tabletInfo.EndPoint()
	if err != nil {
		return fmt.Errorf("cannot get EndPoint from tablet record: %v", err)
	}

	// pass in a non-UNKNOWN tablet type to not use sessionId
	conn, err := tabletconn.GetDialer()(ctx, ep, "", "", pb.TabletType_MASTER, *connectTimeout)
	if err != nil {
		return fmt.Errorf("cannot connect to tablet %v: %v", tabletAlias, err)
	}

	stream, errFunc, err := conn.StreamHealth(ctx)
	if err != nil {
		return err
	}
	for i := 0; i < *count; i++ {
		shr, ok := <-stream
		if !ok {
			return fmt.Errorf("stream ended early: %v", errFunc())
		}
		data, err := json.Marshal(shr)
		if err != nil {
			wr.Logger().Errorf("cannot json-marshal structure: %v", err)
		} else {
			wr.Logger().Printf("%v\n", string(data))
		}
	}
	return nil
}

func commandReparentTablet(ctx context.Context, wr *wrangler.Wrangler, subFlags *flag.FlagSet, args []string) error {
	if *disableActiveReparents {
		return fmt.Errorf("active reparent actions disable in this cluster")
	}

	if err := subFlags.Parse(args); err != nil {
		return err
	}
	if subFlags.NArg() != 1 {
		return fmt.Errorf("action ReparentTablet requires <tablet alias>")
	}
	tabletAlias, err := topo.ParseTabletAliasString(subFlags.Arg(0))
	if err != nil {
		return err
	}
	return wr.ReparentTablet(ctx, tabletAlias)
}

func commandVtTabletBegin(ctx context.Context, wr *wrangler.Wrangler, subFlags *flag.FlagSet, args []string) error {
	keyspace := subFlags.String("keyspace", "", "keyspace the tablet belongs to")
	shard := subFlags.String("shard", "", "shard the tablet belongs to")
	tabletType := subFlags.String("tablet_type", "unknown", "tablet type we expect from the tablet (use unknown to use sessionId)")
	connectTimeout := subFlags.Duration("connect_timeout", 30*time.Second, "Connection timeout for vttablet client")
	if err := subFlags.Parse(args); err != nil {
		return err
	}
	if subFlags.NArg() != 1 {
		return fmt.Errorf("the <tablet_alias> argument is required for the VtTabletBegin command")
	}
	tt, err := topo.ParseTabletType(*tabletType)
	if err != nil {
		return err
	}
	tabletAlias, err := topo.ParseTabletAliasString(subFlags.Arg(0))
	if err != nil {
		return err
	}
	tabletInfo, err := wr.TopoServer().GetTablet(ctx, tabletAlias)
	if err != nil {
		return err
	}
	ep, err := topo.TabletEndPoint(tabletInfo.Tablet)
	if err != nil {
		return fmt.Errorf("cannot get EndPoint from tablet record: %v", err)
	}

	conn, err := tabletconn.GetDialer()(ctx, ep, *keyspace, *shard, tt, *connectTimeout)
	if err != nil {
		return fmt.Errorf("cannot connect to tablet %v: %v", tabletAlias, err)
	}
	defer conn.Close()

	transactionID, err := conn.Begin(ctx)
	if err != nil {
		return fmt.Errorf("Begin failed: %v", err)
	}
	result := map[string]int64{
		"transaction_id": transactionID,
	}
	return printJSON(wr, result)
}

func commandVtTabletExecute(ctx context.Context, wr *wrangler.Wrangler, subFlags *flag.FlagSet, args []string) error {
	transactionID := subFlags.Int("transaction_id", 0, "transaction id to use, if inside a transaction.")
	bindVariables := newBindvars(subFlags)
	keyspace := subFlags.String("keyspace", "", "keyspace the tablet belongs to")
	shard := subFlags.String("shard", "", "shard the tablet belongs to")
	tabletType := subFlags.String("tablet_type", "unknown", "tablet type we expect from the tablet (use unknown to use sessionId)")
	connectTimeout := subFlags.Duration("connect_timeout", 30*time.Second, "Connection timeout for vttablet client")
	if err := subFlags.Parse(args); err != nil {
		return err
	}
	if subFlags.NArg() != 2 {
		return fmt.Errorf("the <tablet_alis> and <sql> arguments are required for the VtTabletExecute command")
	}
	tt, err := parseTabletType3(*tabletType)
	if err != nil {
		return err
	}
	tabletAlias, err := topo.ParseTabletAliasString(subFlags.Arg(0))
	if err != nil {
		return err
	}
	tabletInfo, err := wr.TopoServer().GetTablet(ctx, tabletAlias)
	if err != nil {
		return err
	}
	ep, err := tabletInfo.EndPoint()
	if err != nil {
		return fmt.Errorf("cannot get EndPoint from tablet record: %v", err)
	}

	conn, err := tabletconn.GetDialer()(ctx, ep, *keyspace, *shard, tt, *connectTimeout)
	if err != nil {
		return fmt.Errorf("cannot connect to tablet %v: %v", tabletAlias, err)
	}
	defer conn.Close()

	qr, err := conn.Execute(ctx, subFlags.Arg(1), *bindVariables, int64(*transactionID))
	if err != nil {
		return fmt.Errorf("Execute failed: %v", err)
	}
	wr.Logger().Printf("%v\n", jscfg.ToJSON(qr))
	return nil
}

func commandDemoteMaster(ctx context.Context, wr *wrangler.Wrangler, subFlags *flag.FlagSet, args []string) error {
	if *disableActiveReparents {
		return fmt.Errorf("active reparent actions disable in this cluster")
	}

	if err := subFlags.Parse(args); err != nil {
		return err
	}
	if subFlags.NArg() != 1 {
		return fmt.Errorf("action DemoteMaster requires <tablet alias>")
	}
	tabletAlias, err := topo.ParseTabletAliasString(subFlags.Arg(0))
	if err != nil {
		return err
	}
	tabletInfo, err := wr.TopoServer().GetTablet(ctx, tabletAlias)
	if err != nil {
		return err
	}
	_, err = wr.TabletManagerClient().DemoteMaster(ctx, tabletInfo)
	return err
}

func commandEmergencyReparentShard(ctx context.Context, wr *wrangler.Wrangler, subFlags *flag.FlagSet, args []string) error {
	if *disableActiveReparents {
		return fmt.Errorf("active reparent actions disable in this cluster")
	}

	waitSlaveTimeout := subFlags.Duration("wait_slave_timeout", 30*time.Second, "time to wait for slaves to catch up in reparenting")
	if err := subFlags.Parse(args); err != nil {
		return err
	}
	if subFlags.NArg() != 2 {
		return fmt.Errorf("action EmergencyReparentShard requires <keyspace/shard> <tablet alias>")
	}

	keyspace, shard, err := topo.ParseKeyspaceShardString(subFlags.Arg(0))
	if err != nil {
		return err
	}
	tabletAlias, err := topo.ParseTabletAliasString(subFlags.Arg(1))
	if err != nil {
		return err
	}
	return wr.EmergencyReparentShard(ctx, keyspace, shard, tabletAlias, *waitSlaveTimeout)
}

func commandInitShardMaster(ctx context.Context, wr *wrangler.Wrangler, subFlags *flag.FlagSet, args []string) error {
	if *disableActiveReparents {
		return fmt.Errorf("active reparent actions disable in this cluster")
	}

	force := subFlags.Bool("force", false, "will force the reparent even if the provided tablet is not a master or the shard master")
	waitSlaveTimeout := subFlags.Duration("wait_slave_timeout", 30*time.Second, "time to wait for slaves to catch up in reparenting")
	if err := subFlags.Parse(args); err != nil {
		return err
	}
	if subFlags.NArg() != 2 {
		return fmt.Errorf("action InitShardMaster requires <keyspace/shard> <tablet alias>")
	}
	keyspace, shard, err := topo.ParseKeyspaceShardString(subFlags.Arg(0))
	if err != nil {
		return err
	}
	tabletAlias, err := topo.ParseTabletAliasString(subFlags.Arg(1))
	if err != nil {
		return err
	}
	return wr.InitShardMaster(ctx, keyspace, shard, tabletAlias, *force, *waitSlaveTimeout)
}

func (zkts *Server) GetReplicationPaths(keyspace, shard, repPath string) ([]topo.TabletAlias, error) {
	replicationPath := path.Join(globalKeyspacesPath, keyspace, "shards", shard, repPath)
	children, _, err := zkts.zconn.Children(replicationPath)
	if err != nil {
		if zookeeper.IsError(err, zookeeper.ZNONODE) {
			err = topo.ErrNoNode
		}
		return nil, err
	}

	result := make([]topo.TabletAlias, 0, len(children))
	for _, child := range children {
		// 'action' and 'actionlog' can only be present at the toplevel
		if (repPath == "" || repPath == "/") && (child == "action" || child == "actionlog") {
			continue
		}
		alias, err := topo.ParseTabletAliasString(child)
		if err != nil {
			return nil, err
		}
		result = append(result, alias)
	}
	return result, nil
}

//.........这里部分代码省略.........

		keyspace := r.FormValue("keyspace")
		if keyspace == "" {
			http.Error(w, "no keyspace provided", http.StatusBadRequest)
			return
		}
		shard := r.FormValue("shard")
		if shard == "" {
			http.Error(w, "no shard provided", http.StatusBadRequest)
			return
		}
		result := actionRepo.ApplyShardAction(action, keyspace, shard, r)

		templateLoader.ServeTemplate("action.html", result, w, r)
	})

	// tablet actions
	http.HandleFunc("/tablet_actions", func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseForm(); err != nil {
			httpError(w, "cannot parse form: %s", err)
			return
		}
		action := r.FormValue("action")
		if action == "" {
			http.Error(w, "no action provided", http.StatusBadRequest)
			return
		}

		alias := r.FormValue("alias")
		if alias == "" {
			http.Error(w, "no alias provided", http.StatusBadRequest)
			return
		}
		tabletAlias, err := topo.ParseTabletAliasString(alias)
		if err != nil {
			http.Error(w, "bad alias provided", http.StatusBadRequest)
			return
		}
		result := actionRepo.ApplyTabletAction(action, tabletAlias, r)

		templateLoader.ServeTemplate("action.html", result, w, r)
	})

	// topology server
	http.HandleFunc("/dbtopo", func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseForm(); err != nil {
			httpError(w, "cannot parse form: %s", err)
			return
		}
		result := DbTopologyResult{}
		topology, err := topotools.DbTopology(wr.TopoServer())
		if err != nil {
			result.Error = err.Error()
		} else {
			result.Topology = topology
		}
		templateLoader.ServeTemplate("dbtopo.html", result, w, r)
	})

	// serving graph
	http.HandleFunc("/serving_graph/", func(w http.ResponseWriter, r *http.Request) {
		parts := strings.Split(r.URL.Path, "/")

		cell := parts[len(parts)-1]
		if cell == "" {
			cells, err := ts.GetKnownCells()

//.........这里部分代码省略.........
		if shard == "" {
			return ts.GetShardNames(ctx, keyspace)
		}

		// Perform an action on a shard.
		if r.Method == "POST" {
			if err := r.ParseForm(); err != nil {
				return nil, err
			}
			action := r.FormValue("action")
			if action == "" {
				return nil, errors.New("must specify action")
			}
			return actions.ApplyShardAction(ctx, action, keyspace, shard, r), nil
		}

		// Get the shard record.
		return ts.GetShard(ctx, keyspace, shard)
	})

	// Tablets
	handleCollection("tablets", func(r *http.Request) (interface{}, error) {
		tabletPath := getItemPath(r.URL.Path)

		// List tablets based on query params.
		if tabletPath == "" {
			if err := r.ParseForm(); err != nil {
				return nil, err
			}
			shardRef := r.FormValue("shard")
			cell := r.FormValue("cell")

			if shardRef != "" {
				// Look up by keyspace/shard, and optionally cell.
				keyspace, shard, err := topo.ParseKeyspaceShardString(shardRef)
				if err != nil {
					return nil, err
				}
				if cell != "" {
					return topo.FindAllTabletAliasesInShardByCell(ctx, ts, keyspace, shard, []string{cell})
				}
				return topo.FindAllTabletAliasesInShard(ctx, ts, keyspace, shard)
			}

			// Get all tablets in a cell.
			if cell == "" {
				return nil, errors.New("cell param required")
			}
			return ts.GetTabletsByCell(ctx, cell)
		}

		// Get tablet health.
		if parts := strings.Split(tabletPath, "/"); len(parts) == 2 && parts[1] == "health" {
			tabletAlias, err := topo.ParseTabletAliasString(parts[0])
			if err != nil {
				return nil, err
			}
			return tabletHealthCache.Get(ctx, tabletAlias)
		}

		tabletAlias, err := topo.ParseTabletAliasString(tabletPath)
		if err != nil {
			return nil, err
		}

		// Perform an action on a tablet.
		if r.Method == "POST" {
			if err := r.ParseForm(); err != nil {
				return nil, err
			}
			action := r.FormValue("action")
			if action == "" {
				return nil, errors.New("must specify action")
			}
			return actions.ApplyTabletAction(ctx, action, tabletAlias, r), nil
		}

		// Get the tablet record.
		return ts.GetTablet(ctx, tabletAlias)
	})

	// EndPoints
	handleCollection("endpoints", func(r *http.Request) (interface{}, error) {
		// We expect cell/keyspace/shard/tabletType.
		epPath := getItemPath(r.URL.Path)
		parts := strings.Split(epPath, "/")
		if len(parts) != 4 {
			return nil, fmt.Errorf("invalid cell/keyspace/shard/tabletType: %q", epPath)
		}

		if parts[3] == "" {
			// tabletType is empty, so list the tablet types.
			return ts.GetSrvTabletTypesPerShard(ctx, parts[0], parts[1], parts[2])
		}

		// Get the endpoints object for a specific type.
		ep, _, err := ts.GetEndPoints(ctx, parts[0], parts[1], parts[2], topo.TabletType(parts[3]))
		return ep, err
	})
}

//.........这里部分代码省略.........
	// Tablets
	handleCollection("tablets", func(r *http.Request) (interface{}, error) {
		tabletPath := getItemPath(r.URL.Path)

		// List tablets based on query params.
		if tabletPath == "" {
			if err := r.ParseForm(); err != nil {
				return nil, err
			}
			shardRef := r.FormValue("shard")
			cell := r.FormValue("cell")

			if shardRef != "" {
				// Look up by keyspace/shard, and optionally cell.
				keyspace, shard, err := topo.ParseKeyspaceShardString(shardRef)
				if err != nil {
					return nil, err
				}
				if cell != "" {
					return topo.FindAllTabletAliasesInShardByCell(ctx, ts, keyspace, shard, []string{cell})
				}
				return topo.FindAllTabletAliasesInShard(ctx, ts, keyspace, shard)
			}

			// Get all tablets in a cell.
			if cell == "" {
				return nil, errors.New("cell param required")
			}
			return ts.GetTabletsByCell(ctx, cell)
		}

		// Get tablet health.
		if parts := strings.Split(tabletPath, "/"); len(parts) == 2 && parts[1] == "health" {
			tabletAlias, err := topo.ParseTabletAliasString(parts[0])
			if err != nil {
				return nil, err
			}
			return tabletHealthCache.Get(ctx, tabletAlias)
		}

		tabletAlias, err := topo.ParseTabletAliasString(tabletPath)
		if err != nil {
			return nil, err
		}

		// Perform an action on a tablet.
		if r.Method == "POST" {
			if err := r.ParseForm(); err != nil {
				return nil, err
			}
			action := r.FormValue("action")
			if action == "" {
				return nil, errors.New("must specify action")
			}
			return actions.ApplyTabletAction(ctx, action, tabletAlias, r), nil
		}

		// Get the tablet record.
		return ts.GetTablet(ctx, tabletAlias)
	})

	// EndPoints
	handleCollection("endpoints", func(r *http.Request) (interface{}, error) {
		// We expect cell/keyspace/shard/tabletType.
		epPath := getItemPath(r.URL.Path)
		parts := strings.Split(epPath, "/")

//.........这里部分代码省略.........
			return
		}

		keyspace := r.FormValue("keyspace")
		if keyspace == "" {
			http.Error(w, "no keyspace provided", http.StatusBadRequest)
			return
		}
		shard := r.FormValue("shard")
		if shard == "" {
			http.Error(w, "no shard provided", http.StatusBadRequest)
			return
		}
		result := actionRepo.ApplyShardAction(action, keyspace, shard, r)

		templateLoader.ServeTemplate("action.html", result, w, r)
	})
	http.HandleFunc("/tablet_actions", func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseForm(); err != nil {
			httpError(w, "cannot parse form: %s", err)
			return
		}
		action := r.FormValue("action")
		if action == "" {
			http.Error(w, "no action provided", http.StatusBadRequest)
			return
		}

		alias := r.FormValue("alias")
		if alias == "" {
			http.Error(w, "no alias provided", http.StatusBadRequest)
			return
		}
		tabletAlias, err := topo.ParseTabletAliasString(alias)
		if err != nil {
			http.Error(w, "bad alias provided", http.StatusBadRequest)
			return
		}
		result := actionRepo.ApplyTabletAction(action, tabletAlias, r)

		templateLoader.ServeTemplate("action.html", result, w, r)
	})
	http.HandleFunc("/dbtopo", func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseForm(); err != nil {
			httpError(w, "cannot parse form: %s", err)
			return
		}
		result := DbTopologyResult{}
		topology, err := wr.DbTopology()
		if err != nil {
			result.Error = err.Error()
		} else {
			result.Topology = topology
		}
		templateLoader.ServeTemplate("dbtopo.html", result, w, r)
	})
	http.HandleFunc("/serving_graph/", func(w http.ResponseWriter, r *http.Request) {
		parts := strings.Split(r.URL.Path, "/")

		cell := parts[len(parts)-1]
		if cell == "" {
			cells, err := wr.TopoServer().GetKnownCells()
			if err != nil {
				httpError(w, "cannot get known cells: %v", err)
				return
			} else {

//.........这里部分代码省略.........
		keyspace := r.FormValue("keyspace")
		if keyspace == "" {
			http.Error(w, "no keyspace provided", http.StatusBadRequest)
			return
		}
		shard := r.FormValue("shard")
		if shard == "" {
			http.Error(w, "no shard provided", http.StatusBadRequest)
			return
		}
		ctx := context.Background()
		result := actionRepo.ApplyShardAction(ctx, action, keyspace, shard, r)

		templateLoader.ServeTemplate("action.html", result, w, r)
	})

	// tablet actions
	http.HandleFunc("/tablet_actions", func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseForm(); err != nil {
			httpErrorf(w, r, "cannot parse form: %s", err)
			return
		}
		action := r.FormValue("action")
		if action == "" {
			http.Error(w, "no action provided", http.StatusBadRequest)
			return
		}

		alias := r.FormValue("alias")
		if alias == "" {
			http.Error(w, "no alias provided", http.StatusBadRequest)
			return
		}
		tabletAlias, err := topo.ParseTabletAliasString(alias)
		if err != nil {
			http.Error(w, "bad alias provided", http.StatusBadRequest)
			return
		}
		ctx := context.Background()
		result := actionRepo.ApplyTabletAction(ctx, action, tabletAlias, r)

		templateLoader.ServeTemplate("action.html", result, w, r)
	})

	// topology server
	http.HandleFunc("/dbtopo", func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseForm(); err != nil {
			httpErrorf(w, r, "cannot parse form: %s", err)
			return
		}
		result := DbTopologyResult{}
		ctx := context.TODO()
		topology, err := topotools.DbTopology(ctx, ts)
		if err == nil && modifyDbTopology != nil {
			err = modifyDbTopology(ctx, ts, topology)
		}
		if err != nil {
			result.Error = err.Error()
		} else {
			result.Topology = topology
		}
		templateLoader.ServeTemplate("dbtopo.html", result, w, r)
	})

	// serving graph
	http.HandleFunc("/serving_graph/", func(w http.ResponseWriter, r *http.Request) {

func initAPI(ctx context.Context, ts topo.Server) {
	// Get Cells
	handleGet("cells", func(r *http.Request) (interface{}, error) {
		if getItemPath(r.URL.Path) != "" {
			return nil, errors.New("cells can only be listed, not retrieved")
		}
		return ts.GetKnownCells(ctx)
	})

	// Get Keyspaces
	handleGet("keyspaces", func(r *http.Request) (interface{}, error) {
		keyspace := getItemPath(r.URL.Path)
		if keyspace == "" {
			return ts.GetKeyspaces(ctx)
		}
		return ts.GetKeyspace(ctx, keyspace)
	})

	// Get Shards
	handleGet("shards", func(r *http.Request) (interface{}, error) {
		shardPath := getItemPath(r.URL.Path)
		if !strings.Contains(shardPath, "/") {
			return nil, fmt.Errorf("invalid shard path: %q", shardPath)
		}
		parts := strings.SplitN(shardPath, "/", 2)
		if parts[1] == "" {
			// It's just a keyspace. List the shards.
			return ts.GetShardNames(ctx, parts[0])
		}
		// It's a keyspace/shard reference.
		return ts.GetShard(ctx, parts[0], parts[1])
	})

	// Get Tablets
	handleGet("tablets", func(r *http.Request) (interface{}, error) {
		tabletPath := getItemPath(r.URL.Path)
		if tabletPath == "" {
			// List tablets based on query params.
			if err := r.ParseForm(); err != nil {
				return nil, err
			}
			shardRef := r.FormValue("shard")
			cell := r.FormValue("cell")

			if shardRef != "" {
				// Look up by keyspace/shard, and optionally cell.
				keyspace, shard, err := topo.ParseKeyspaceShardString(shardRef)
				if err != nil {
					return nil, err
				}
				if cell != "" {
					return topo.FindAllTabletAliasesInShardByCell(ctx, ts, keyspace, shard, []string{cell})
				}
				return topo.FindAllTabletAliasesInShard(ctx, ts, keyspace, shard)
			}

			// Get all tablets in a cell.
			if cell == "" {
				return nil, errors.New("cell param required")
			}
			return ts.GetTabletsByCell(ctx, cell)
		}

		// Get a specific tablet.
		tabletAlias, err := topo.ParseTabletAliasString(tabletPath)
		if err != nil {
			return nil, err
		}
		return ts.GetTablet(ctx, tabletAlias)
	})

	// Get EndPoints
	handleGet("endpoints", func(r *http.Request) (interface{}, error) {
		// We expect cell/keyspace/shard/tabletType.
		epPath := getItemPath(r.URL.Path)
		parts := strings.Split(epPath, "/")
		if len(parts) != 4 {
			return nil, fmt.Errorf("invalid cell/keyspace/shard/tabletType: %q", epPath)
		}

		if parts[3] == "" {
			// tabletType is empty, so list the tablet types.
			return ts.GetSrvTabletTypesPerShard(ctx, parts[0], parts[1], parts[2])
		}

		// Get the endpoints object for a specific type.
		ep, _, err := ts.GetEndPoints(ctx, parts[0], parts[1], parts[2], topo.TabletType(parts[3]))
		return ep, err
	})
}

//.........这里部分代码省略.........
	actionRepo.RegisterShardAction("ValidatePermissionsShard",
		func(wr *wrangler.Wrangler, keyspace, shard string, r *http.Request) (string, error) {
			return "", wr.ValidatePermissionsShard(keyspace, shard)
		})

	// tablet actions
	actionRepo.RegisterTabletAction("RpcPing",
		func(wr *wrangler.Wrangler, tabletAlias topo.TabletAlias, r *http.Request) (string, error) {
			return "", wr.ActionInitiator().RpcPing(tabletAlias, 10*time.Second)
		})

	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		templateLoader.ServeTemplate("index.html", indexContent, w, r)
	})
	http.HandleFunc("/keyspace_actions", func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseForm(); err != nil {
			httpError(w, "cannot parse form: %s", err)
			return
		}
		action := r.FormValue("action")
		if action == "" {
			http.Error(w, "no action provided", http.StatusBadRequest)
			return
		}

		keyspace := r.FormValue("keyspace")
		if keyspace == "" {
			http.Error(w, "no keyspace provided", http.StatusBadRequest)
			return
		}
		result := actionRepo.ApplyKeyspaceAction(action, keyspace, r)

		templateLoader.ServeTemplate("action.html", result, w, r)
	})
	http.HandleFunc("/shard_actions", func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseForm(); err != nil {
			httpError(w, "cannot parse form: %s", err)
			return
		}
		action := r.FormValue("action")
		if action == "" {
			http.Error(w, "no action provided", http.StatusBadRequest)
			return
		}

		keyspace := r.FormValue("keyspace")
		if keyspace == "" {
			http.Error(w, "no keyspace provided", http.StatusBadRequest)
			return
		}
		shard := r.FormValue("shard")
		if shard == "" {
			http.Error(w, "no shard provided", http.StatusBadRequest)
			return
		}
		result := actionRepo.ApplyShardAction(action, keyspace, shard, r)

		templateLoader.ServeTemplate("action.html", result, w, r)
	})
	http.HandleFunc("/tablet_actions", func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseForm(); err != nil {
			httpError(w, "cannot parse form: %s", err)
			return
		}
		action := r.FormValue("action")
		if action == "" {
			http.Error(w, "no action provided", http.StatusBadRequest)
			return
		}

		alias := r.FormValue("alias")
		if alias == "" {
			http.Error(w, "no alias provided", http.StatusBadRequest)
			return
		}
		tabletAlias, err := topo.ParseTabletAliasString(alias)
		if err != nil {
			http.Error(w, "bad alias provided", http.StatusBadRequest)
			return
		}
		result := actionRepo.ApplyTabletAction(action, tabletAlias, r)

		templateLoader.ServeTemplate("action.html", result, w, r)
	})
	http.HandleFunc("/dbtopo", func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseForm(); err != nil {
			httpError(w, "cannot parse form: %s", err)
			return
		}
		result := DbTopologyResult{}
		topology, err := wr.DbTopology()
		if err != nil {
			result.Error = err.Error()
		} else {
			result.Topology = topology
		}
		templateLoader.ServeTemplate("dbtopo.html", result, w, r)
	})
	log.Fatalf("%s", http.ListenAndServe(fmt.Sprintf(":%d", *port), nil))
}