Golang Server.GetEndPoints方法代码示例

func retryUpdateEndpoints(ctx context.Context, ts topo.Server, cell, keyspace, shard string, tabletType pb.TabletType, create bool, updateFunc func(*pb.EndPoints) bool) error {
	for {
		select {
		case <-ctx.Done():
			return ctx.Err()
		default:
		}

		// Get or create EndPoints list.
		endpoints, version, err := ts.GetEndPoints(ctx, cell, keyspace, shard, tabletType)
		if err == topo.ErrNoNode && create {
			// Create instead of updating.
			endpoints = &pb.EndPoints{}
			if !updateFunc(endpoints) {
				// Nothing changed.
				return nil
			}
			err = ts.CreateEndPoints(ctx, cell, keyspace, shard, tabletType, endpoints)
			if err == topo.ErrNodeExists {
				// Someone else beat us to it. Try again.
				continue
			}
			return err
		}
		if err != nil {
			return err
		}

		// We got an existing EndPoints list. Try to update.
		if !updateFunc(endpoints) {
			// Nothing changed.
			return nil
		}

		// If there's nothing left, we should delete the list entirely.
		if len(endpoints.Entries) == 0 {
			err = ts.DeleteEndPoints(ctx, cell, keyspace, shard, tabletType, version)
			switch err {
			case topo.ErrNoNode:
				// Someone beat us to it, which is fine.
				return nil
			case topo.ErrBadVersion:
				// Someone else updated the list. Try again.
				continue
			}
			return err
		}

		err = ts.UpdateEndPoints(ctx, cell, keyspace, shard, tabletType, endpoints, version)
		if err == topo.ErrBadVersion || (err == topo.ErrNoNode && create) {
			// Someone else updated or deleted the list in the meantime. Try again.
			continue
		}
		return err
	}
}

func getEndPointsVersions(ctx context.Context, ts topo.Server, cell, keyspace, shard string) (map[pb.TabletType]int64, error) {
	// Get all existing tablet types.
	tabletTypes, err := ts.GetSrvTabletTypesPerShard(ctx, cell, keyspace, shard)
	if err != nil {
		if err == topo.ErrNoNode {
			// This just means there aren't any EndPoints lists yet.
			return nil, nil
		}
		return nil, err
	}

	// Get node versions.
	wg := sync.WaitGroup{}
	errs := concurrency.AllErrorRecorder{}
	versions := make(map[pb.TabletType]int64)
	mu := sync.Mutex{}

	for _, tabletType := range tabletTypes {
		wg.Add(1)
		go func(tabletType pb.TabletType) {
			defer wg.Done()

			_, version, err := ts.GetEndPoints(ctx, cell, keyspace, shard, tabletType)
			if err != nil && err != topo.ErrNoNode {
				errs.RecordError(err)
				return
			}

			mu.Lock()
			versions[tabletType] = version
			mu.Unlock()
		}(tabletType)
	}

	wg.Wait()
	return versions, errs.Error()
}

//.........这里部分代码省略.........
				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 := topoproto.ParseTabletAlias(parts[0])
			if err != nil {
				return nil, err
			}
			return tabletHealthCache.Get(ctx, tabletAlias)
		}

		tabletAlias, err := topoproto.ParseTabletAlias(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])
		}

		tabletType, err := topoproto.ParseTabletType(parts[3])
		if err != nil {
			return nil, fmt.Errorf("invalid tablet type %v: %v", parts[3], err)
		}

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

	// Schema Change
	http.HandleFunc(apiPrefix+"schema/apply", func(w http.ResponseWriter, r *http.Request) {
		req := struct{ Keyspace, SQL string }{}
		if err := unmarshalRequest(r, &req); err != nil {
			httpErrorf(w, r, "can't unmarshal request: %v", err)
			return
		}

		executor := schemamanager.NewTabletExecutor(
			tmclient.NewTabletManagerClient(),
			ts)

		schemamanager.Run(ctx,
			schemamanager.NewUIController(req.SQL, req.Keyspace, w), executor)
	})

	// VSchema
	http.HandleFunc(apiPrefix+"vschema/", func(w http.ResponseWriter, r *http.Request) {
		// Save VSchema
		if r.Method == "POST" {
			vschema, err := ioutil.ReadAll(r.Body)
			if err != nil {
				httpErrorf(w, r, "can't read request body: %v", err)
				return
			}
			if err := ts.SaveVSchema(ctx, string(vschema)); err != nil {
				httpErrorf(w, r, "can't save vschema: %v", err)
			}
			return
		}

		// Get VSchema
		vschema, err := ts.GetVSchema(ctx)
		if err != nil {
			httpErrorf(w, r, "can't get vschema: %v", err)
			return
		}
		w.Header().Set("Content-Type", jsonContentType)
		w.Write([]byte(vschema))
	})
}

// DbServingGraph returns the ServingGraph for the given cell.
func DbServingGraph(ctx context.Context, ts topo.Server, cell string) (servingGraph *ServingGraph) {
	servingGraph = &ServingGraph{
		Cell:      cell,
		Keyspaces: make(map[string]*KeyspaceNodes),
	}
	rec := concurrency.AllErrorRecorder{}

	keyspaces, err := ts.GetSrvKeyspaceNames(ctx, cell)
	if err != nil {
		servingGraph.Errors = append(servingGraph.Errors, fmt.Sprintf("GetSrvKeyspaceNames failed: %v", err))
		return
	}
	wg := sync.WaitGroup{}
	servingTypes := []topo.TabletType{topo.TYPE_MASTER, topo.TYPE_REPLICA, topo.TYPE_RDONLY}
	for _, keyspace := range keyspaces {
		kn := newKeyspaceNodes()
		servingGraph.Keyspaces[keyspace] = kn
		wg.Add(1)
		go func(keyspace string, kn *KeyspaceNodes) {
			defer wg.Done()

			ks, err := ts.GetSrvKeyspace(ctx, cell, keyspace)
			if err != nil {
				rec.RecordError(fmt.Errorf("GetSrvKeyspace(%v, %v) failed: %v", cell, keyspace, err))
				return
			}
			kn.ServedFrom = ks.ServedFrom

			displayedShards := make(map[string]bool)
			for _, partitionTabletType := range servingTypes {
				kp, ok := ks.Partitions[partitionTabletType]
				if !ok {
					continue
				}
				for _, srvShard := range kp.ShardReferences {
					shard := srvShard.Name
					if displayedShards[shard] {
						continue
					}
					displayedShards[shard] = true

					sn := &ShardNodes{
						Name:        shard,
						TabletNodes: make(TabletNodesByType),
					}
					kn.ShardNodes = append(kn.ShardNodes, sn)
					wg.Add(1)
					go func(shard string, sn *ShardNodes) {
						defer wg.Done()
						tabletTypes, err := ts.GetSrvTabletTypesPerShard(ctx, cell, keyspace, shard)
						if err != nil {
							rec.RecordError(fmt.Errorf("GetSrvTabletTypesPerShard(%v, %v, %v) failed: %v", cell, keyspace, shard, err))
							return
						}
						for _, tabletType := range tabletTypes {
							endPoints, _, err := ts.GetEndPoints(ctx, cell, keyspace, shard, tabletType)
							if err != nil {
								rec.RecordError(fmt.Errorf("GetEndPoints(%v, %v, %v, %v) failed: %v", cell, keyspace, shard, tabletType, err))
								continue
							}
							for _, endPoint := range endPoints.Entries {
								sn.TabletNodes[tabletType] = append(sn.TabletNodes[tabletType], newTabletNodeFromEndPoint(endPoint, cell))
							}
						}
					}(shard, sn)
				}
			}
		}(keyspace, kn)
	}
	wg.Wait()
	servingGraph.Errors = rec.ErrorStrings()
	return
}

// DbServingGraph returns the ServingGraph for the given cell.
func DbServingGraph(ctx context.Context, ts topo.Server, cell string) (servingGraph *ServingGraph) {
	servingGraph = &ServingGraph{
		Cell:      cell,
		Keyspaces: make(map[string]*KeyspaceNodes),
	}
	rec := concurrency.AllErrorRecorder{}

	keyspaces, err := ts.GetSrvKeyspaceNames(ctx, cell)
	if err != nil {
		servingGraph.Errors = append(servingGraph.Errors, fmt.Sprintf("GetSrvKeyspaceNames failed: %v", err))
		return
	}
	wg := sync.WaitGroup{}
	servingTypes := []pb.TabletType{pb.TabletType_MASTER, pb.TabletType_REPLICA, pb.TabletType_RDONLY}
	for _, keyspace := range keyspaces {
		kn := newKeyspaceNodes()
		servingGraph.Keyspaces[keyspace] = kn
		wg.Add(1)
		go func(keyspace string, kn *KeyspaceNodes) {
			defer wg.Done()

			ks, err := ts.GetSrvKeyspace(ctx, cell, keyspace)
			if err != nil {
				rec.RecordError(fmt.Errorf("GetSrvKeyspace(%v, %v) failed: %v", cell, keyspace, err))
				return
			}
			for _, sf := range ks.ServedFrom {
				kn.ServedFrom[strings.ToLower(sf.TabletType.String())] = sf.Keyspace
			}

			displayedShards := make(map[string]bool)
			for _, partitionTabletType := range servingTypes {
				kp := topoproto.SrvKeyspaceGetPartition(ks, partitionTabletType)
				if kp == nil {
					continue
				}
				for _, srvShard := range kp.ShardReferences {
					shard := srvShard.Name
					if displayedShards[shard] {
						continue
					}
					displayedShards[shard] = true

					sn := &ShardNodes{
						Name: shard,
					}
					kn.ShardNodes = append(kn.ShardNodes, sn)
					wg.Add(1)
					go func(shard string, sn *ShardNodes) {
						defer wg.Done()
						tabletTypes, err := ts.GetSrvTabletTypesPerShard(ctx, cell, keyspace, shard)
						if err != nil {
							rec.RecordError(fmt.Errorf("GetSrvTabletTypesPerShard(%v, %v, %v) failed: %v", cell, keyspace, shard, err))
							return
						}
						for _, tabletType := range tabletTypes {
							endPoints, _, err := ts.GetEndPoints(ctx, cell, keyspace, shard, tabletType)
							if err != nil {
								rec.RecordError(fmt.Errorf("GetEndPoints(%v, %v, %v, %v) failed: %v", cell, keyspace, shard, tabletType, err))
								continue
							}
							for _, endPoint := range endPoints.Entries {
								var tabletNode *TabletNodesByType
								for _, t := range sn.TabletNodes {
									if t.TabletType == tabletType {
										tabletNode = t
										break
									}
								}
								if tabletNode == nil {
									tabletNode = &TabletNodesByType{
										TabletType: tabletType,
									}
									sn.TabletNodes = append(sn.TabletNodes, tabletNode)
								}
								tabletNode.Nodes = append(tabletNode.Nodes, newTabletNodeFromEndPoint(endPoint, cell))
							}
						}
					}(shard, sn)
				}
			}
		}(keyspace, kn)
	}
	wg.Wait()
	servingGraph.Errors = rec.ErrorStrings()
	return
}

func CheckServingGraph(t *testing.T, ts topo.Server) {
	cell := getLocalCell(t, ts)

	// test individual cell/keyspace/shard/type entries
	if _, err := ts.GetSrvTabletTypesPerShard(cell, "test_keyspace", "-10"); err != topo.ErrNoNode {
		t.Errorf("GetSrvTabletTypesPerShard(invalid): %v", err)
	}
	if _, err := ts.GetEndPoints(cell, "test_keyspace", "-10", topo.TYPE_MASTER); err != topo.ErrNoNode {
		t.Errorf("GetEndPoints(invalid): %v", err)
	}

	endPoints := topo.EndPoints{
		Entries: []topo.EndPoint{
			topo.EndPoint{
				Uid:          1,
				Host:         "host1",
				NamedPortMap: map[string]int{"_vt": 1234, "_mysql": 1235, "_vts": 1236},
			},
		},
	}

	if err := ts.UpdateEndPoints(cell, "test_keyspace", "-10", topo.TYPE_MASTER, &endPoints); err != nil {
		t.Errorf("UpdateEndPoints(master): %v", err)
	}
	if types, err := ts.GetSrvTabletTypesPerShard(cell, "test_keyspace", "-10"); err != nil || len(types) != 1 || types[0] != topo.TYPE_MASTER {
		t.Errorf("GetSrvTabletTypesPerShard(1): %v %v", err, types)
	}

	addrs, err := ts.GetEndPoints(cell, "test_keyspace", "-10", topo.TYPE_MASTER)
	if err != nil {
		t.Errorf("GetEndPoints: %v", err)
	}
	if len(addrs.Entries) != 1 || addrs.Entries[0].Uid != 1 {
		t.Errorf("GetEndPoints(1): %v", addrs)
	}
	if pm := addrs.Entries[0].NamedPortMap; pm["_vt"] != 1234 || pm["_mysql"] != 1235 || pm["_vts"] != 1236 {
		t.Errorf("GetSrcTabletType(1).NamedPortmap: want %v, got %v", endPoints.Entries[0].NamedPortMap, pm)
	}

	if err := ts.UpdateTabletEndpoint(cell, "test_keyspace", "-10", topo.TYPE_REPLICA, &topo.EndPoint{Uid: 2, Host: "host2"}); err != nil {
		t.Errorf("UpdateTabletEndpoint(invalid): %v", err)
	}
	if err := ts.UpdateTabletEndpoint(cell, "test_keyspace", "-10", topo.TYPE_MASTER, &topo.EndPoint{Uid: 1, Host: "host2"}); err != nil {
		t.Errorf("UpdateTabletEndpoint(master): %v", err)
	}
	if addrs, err := ts.GetEndPoints(cell, "test_keyspace", "-10", topo.TYPE_MASTER); err != nil || len(addrs.Entries) != 1 || addrs.Entries[0].Uid != 1 {
		t.Errorf("GetEndPoints(2): %v %v", err, addrs)
	}
	if err := ts.UpdateTabletEndpoint(cell, "test_keyspace", "-10", topo.TYPE_MASTER, &topo.EndPoint{Uid: 3, Host: "host3"}); err != nil {
		t.Errorf("UpdateTabletEndpoint(master): %v", err)
	}
	if addrs, err := ts.GetEndPoints(cell, "test_keyspace", "-10", topo.TYPE_MASTER); err != nil || len(addrs.Entries) != 2 {
		t.Errorf("GetEndPoints(2): %v %v", err, addrs)
	}

	if err := ts.DeleteSrvTabletType(cell, "test_keyspace", "-10", topo.TYPE_REPLICA); err != topo.ErrNoNode {
		t.Errorf("DeleteSrvTabletType(unknown): %v", err)
	}
	if err := ts.DeleteSrvTabletType(cell, "test_keyspace", "-10", topo.TYPE_MASTER); err != nil {
		t.Errorf("DeleteSrvTabletType(master): %v", err)
	}

	// test cell/keyspace/shard entries (SrvShard)
	srvShard := topo.SrvShard{
		ServedTypes: []topo.TabletType{topo.TYPE_MASTER},
		TabletTypes: []topo.TabletType{topo.TYPE_REPLICA, topo.TYPE_RDONLY},
	}
	if err := ts.UpdateSrvShard(cell, "test_keyspace", "-10", &srvShard); err != nil {
		t.Errorf("UpdateSrvShard(1): %v", err)
	}
	if _, err := ts.GetSrvShard(cell, "test_keyspace", "666"); err != topo.ErrNoNode {
		t.Errorf("GetSrvShard(invalid): %v", err)
	}
	if s, err := ts.GetSrvShard(cell, "test_keyspace", "-10"); err != nil ||
		len(s.ServedTypes) != 1 ||
		s.ServedTypes[0] != topo.TYPE_MASTER ||
		len(s.TabletTypes) != 2 ||
		s.TabletTypes[0] != topo.TYPE_REPLICA ||
		s.TabletTypes[1] != topo.TYPE_RDONLY {
		t.Errorf("GetSrvShard(valid): %v", err)
	}

	// test cell/keyspace entries (SrvKeyspace)
	srvKeyspace := topo.SrvKeyspace{
		Partitions: map[topo.TabletType]*topo.KeyspacePartition{
			topo.TYPE_MASTER: &topo.KeyspacePartition{
				Shards: []topo.SrvShard{
					topo.SrvShard{
						ServedTypes: []topo.TabletType{topo.TYPE_MASTER},
					},
				},
			},
		},
		TabletTypes: []topo.TabletType{topo.TYPE_MASTER},
	}
	if err := ts.UpdateSrvKeyspace(cell, "test_keyspace", &srvKeyspace); err != nil {
		t.Errorf("UpdateSrvKeyspace(1): %v", err)
	}
	if _, err := ts.GetSrvKeyspace(cell, "test_keyspace666"); err != topo.ErrNoNode {
		t.Errorf("GetSrvKeyspace(invalid): %v", err)
//.........这里部分代码省略.........

// CheckServingGraph makes sure the serving graph functions work properly.
func CheckServingGraph(ctx context.Context, t *testing.T, ts topo.Server) {
	cell := getLocalCell(ctx, t, ts)

	// test individual cell/keyspace/shard/type entries
	if _, err := ts.GetSrvTabletTypesPerShard(ctx, cell, "test_keyspace", "-10"); err != topo.ErrNoNode {
		t.Errorf("GetSrvTabletTypesPerShard(invalid): %v", err)
	}
	if _, _, err := ts.GetEndPoints(ctx, cell, "test_keyspace", "-10", topo.TYPE_MASTER); err != topo.ErrNoNode {
		t.Errorf("GetEndPoints(invalid): %v", err)
	}

	endPoints := &pb.EndPoints{
		Entries: []*pb.EndPoint{
			&pb.EndPoint{
				Uid:  1,
				Host: "host1",
				PortMap: map[string]int32{
					"vt":    1234,
					"mysql": 1235,
					"grpc":  1236,
				},
			},
		},
	}

	if err := ts.CreateEndPoints(ctx, cell, "test_keyspace", "-10", topo.TYPE_MASTER, endPoints); err != nil {
		t.Fatalf("CreateEndPoints(master): %v", err)
	}
	// Try to create again.
	if err := ts.CreateEndPoints(ctx, cell, "test_keyspace", "-10", topo.TYPE_MASTER, endPoints); err != topo.ErrNodeExists {
		t.Fatalf("CreateEndPoints(master): err = %v, want topo.ErrNodeExists", err)
	}

	// Get version.
	_, version, err := ts.GetEndPoints(ctx, cell, "test_keyspace", "-10", topo.TYPE_MASTER)
	if err != nil {
		t.Fatalf("GetEndPoints(master): %v", err)
	}
	// Make a change.
	tmp := endPoints.Entries[0].Uid
	endPoints.Entries[0].Uid = tmp + 1
	if err := topo.UpdateEndPoints(ctx, ts, cell, "test_keyspace", "-10", topo.TYPE_MASTER, endPoints, -1); err != nil {
		t.Fatalf("UpdateEndPoints(master): %v", err)
	}
	endPoints.Entries[0].Uid = tmp
	// Try to delete with the wrong version.
	if err := ts.DeleteEndPoints(ctx, cell, "test_keyspace", "-10", topo.TYPE_MASTER, version); err != topo.ErrBadVersion {
		t.Fatalf("DeleteEndPoints: err = %v, want topo.ErrBadVersion", err)
	}
	// Delete with the correct version.
	_, version, err = ts.GetEndPoints(ctx, cell, "test_keyspace", "-10", topo.TYPE_MASTER)
	if err != nil {
		t.Fatalf("GetEndPoints(master): %v", err)
	}
	if err := ts.DeleteEndPoints(ctx, cell, "test_keyspace", "-10", topo.TYPE_MASTER, version); err != nil {
		t.Fatalf("DeleteEndPoints: %v", err)
	}
	// Recreate it with an unconditional update.
	if err := topo.UpdateEndPoints(ctx, ts, cell, "test_keyspace", "-10", topo.TYPE_MASTER, endPoints, -1); err != nil {
		t.Fatalf("UpdateEndPoints(master): %v", err)
	}

	if types, err := ts.GetSrvTabletTypesPerShard(ctx, cell, "test_keyspace", "-10"); err != nil || len(types) != 1 || types[0] != topo.TYPE_MASTER {
		t.Errorf("GetSrvTabletTypesPerShard(1): %v %v", err, types)
	}

	// Delete it unconditionally.
	if err := ts.DeleteEndPoints(ctx, cell, "test_keyspace", "-10", topo.TYPE_MASTER, -1); err != nil {
		t.Fatalf("DeleteEndPoints: %v", err)
	}

	// Delete the SrvShard.
	if err := ts.DeleteSrvShard(ctx, cell, "test_keyspace", "-10"); err != nil {
		t.Fatalf("DeleteSrvShard: %v", err)
	}
	if _, err := ts.GetSrvShard(ctx, cell, "test_keyspace", "-10"); err != topo.ErrNoNode {
		t.Errorf("GetSrvShard(deleted) got %v, want ErrNoNode", err)
	}

	// Re-add endpoints.
	if err := topo.UpdateEndPoints(ctx, ts, cell, "test_keyspace", "-10", topo.TYPE_MASTER, endPoints, -1); err != nil {
		t.Fatalf("UpdateEndPoints(master): %v", err)
	}

	addrs, version, err := ts.GetEndPoints(ctx, cell, "test_keyspace", "-10", topo.TYPE_MASTER)
	if err != nil {
		t.Errorf("GetEndPoints: %v", err)
	}
	if len(addrs.Entries) != 1 || addrs.Entries[0].Uid != 1 {
		t.Errorf("GetEndPoints(1): %v", addrs)
	}
	if pm := addrs.Entries[0].PortMap; pm["vt"] != 1234 || pm["mysql"] != 1235 || pm["grpc"] != 1236 {
		t.Errorf("GetSrcTabletType(1).PortMap: want %v, got %v", endPoints.Entries[0].PortMap, pm)
	}

	// Update with the wrong version.
	if err := topo.UpdateEndPoints(ctx, ts, cell, "test_keyspace", "-10", topo.TYPE_MASTER, endPoints, version+1); err != topo.ErrBadVersion {
		t.Fatalf("UpdateEndPoints(master): err = %v, want topo.ErrBadVersion", err)
	}
//.........这里部分代码省略.........

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.........
		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
	})
}