MCP Toolbox for Databases

// Copyright 2025 Google LLC // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. package spannerlistgraphs import ( "context" "encoding/json" "fmt" "strings" "cloud.google.com/go/spanner" yaml "github.com/goccy/go-yaml" "github.com/googleapis/genai-toolbox/internal/sources" "github.com/googleapis/genai-toolbox/internal/tools" "github.com/googleapis/genai-toolbox/internal/util/parameters" "google.golang.org/api/iterator" ) const kind string = "spanner-list-graphs" func init() { if !tools.Register(kind, newConfig) { panic(fmt.Sprintf("tool kind %q already registered", kind)) } } func newConfig(ctx context.Context, name string, decoder *yaml.Decoder) (tools.ToolConfig, error) { actual := Config{Name: name} if err := decoder.DecodeContext(ctx, &actual); err != nil { return nil, err } return actual, nil } type compatibleSource interface { SpannerClient() *spanner.Client DatabaseDialect() string } type Config struct { Name string `yaml:"name" validate:"required"` Kind string `yaml:"kind" validate:"required"` Source string `yaml:"source" validate:"required"` Description string `yaml:"description"` AuthRequired []string `yaml:"authRequired"` } // validate interface var _ tools.ToolConfig = Config{} func (cfg Config) ToolConfigKind() string { return kind } func (cfg Config) Initialize(srcs map[string]sources.Source) (tools.Tool, error) { // Define parameters for the tool allParameters := parameters.Parameters{ parameters.NewStringParameterWithDefault( "graph_names", "", "Optional: A comma-separated list of graph names. If empty, details for all graphs in user-accessible schemas will be listed.", ), parameters.NewStringParameterWithDefault( "output_format", "detailed", "Optional: Use 'simple' to return graph names only or use 'detailed' to return the full information schema.", ), } description := cfg.Description if description == "" { description = "Lists detailed graph schema information (node tables, edge tables, labels and property declarations) as JSON for user-created graphs. Filters by a comma-separated list of graph names. If names are omitted, lists all graphs. The output can be 'simple' (graph names only) or 'detailed' (full schema)." } mcpManifest := tools.GetMcpManifest(cfg.Name, description, cfg.AuthRequired, allParameters, nil) // finish tool setup t := Tool{ Config: cfg, AllParams: allParameters, manifest: tools.Manifest{Description: description, Parameters: allParameters.Manifest(), AuthRequired: cfg.AuthRequired}, mcpManifest: mcpManifest, } return t, nil } // validate interface var _ tools.Tool = Tool{} type Tool struct { Config AllParams parameters.Parameters `yaml:"allParams"` manifest tools.Manifest mcpManifest tools.McpManifest } // processRows iterates over the spanner.RowIterator and converts each row to a map[string]any. func processRows(iter *spanner.RowIterator) ([]any, error) { var out []any defer iter.Stop() for { row, err := iter.Next() if err == iterator.Done { break } if err != nil { return nil, fmt.Errorf("unable to parse row: %w", err) } vMap := make(map[string]any) cols := row.ColumnNames() for i, c := range cols { if c == "object_details" { jsonString := row.ColumnValue(i).AsInterface().(string) var details map[string]interface{} if err := json.Unmarshal([]byte(jsonString), &details); err != nil { return nil, fmt.Errorf("unable to unmarshal JSON: %w", err) } vMap[c] = details } else { vMap[c] = row.ColumnValue(i) } } out = append(out, vMap) } return out, nil } func (t Tool) Invoke(ctx context.Context, resourceMgr tools.SourceProvider, params parameters.ParamValues, accessToken tools.AccessToken) (any, error) { source, err := tools.GetCompatibleSource[compatibleSource](resourceMgr, t.Source, t.Name, t.Kind) if err != nil { return nil, err } // Check dialect here at RUNTIME instead of startup if strings.ToLower(source.DatabaseDialect()) != "googlesql" { return nil, fmt.Errorf("operation not supported: The 'spanner-list-graphs' tool is only available for GoogleSQL dialect databases. Your current database dialect is '%s'", source.DatabaseDialect()) } paramsMap := params.AsMap() graphNames, _ := paramsMap["graph_names"].(string) outputFormat, _ := paramsMap["output_format"].(string) if outputFormat == "" { outputFormat = "detailed" } stmtParams := map[string]interface{}{ "graph_names": graphNames, "output_format": outputFormat, } stmt := spanner.Statement{ SQL: googleSQLStatement, Params: stmtParams, } // Execute the query (read-only) iter := source.SpannerClient().Single().Query(ctx, stmt) results, err := processRows(iter) if err != nil { return nil, fmt.Errorf("unable to execute query: %w", err) } return results, nil } func (t Tool) ParseParams(data map[string]any, claims map[string]map[string]any) (parameters.ParamValues, error) { return parameters.ParseParams(t.AllParams, data, claims) } func (t Tool) Manifest() tools.Manifest { return t.manifest } func (t Tool) McpManifest() tools.McpManifest { return t.mcpManifest } func (t Tool) Authorized(verifiedAuthServices []string) bool { return tools.IsAuthorized(t.AuthRequired, verifiedAuthServices) } func (t Tool) RequiresClientAuthorization(resourceMgr tools.SourceProvider) (bool, error) { return false, nil } func (t Tool) ToConfig() tools.ToolConfig { return t.Config } func (t Tool) GetAuthTokenHeaderName(resourceMgr tools.SourceProvider) (string, error) { return "Authorization", nil } // GoogleSQL statement for listing graphs const googleSQLStatement = ` WITH FilterGraphNames AS ( SELECT DISTINCT TRIM(name) AS GRAPH_NAME FROM UNNEST(IF(@graph_names = '' OR @graph_names IS NULL, ['%'], SPLIT(@graph_names, ','))) AS name ) SELECT PG.PROPERTY_GRAPH_SCHEMA AS schema_name, PG.PROPERTY_GRAPH_NAME AS object_name, CASE WHEN @output_format = 'simple' THEN -- IF format is 'simple', return basic JSON CONCAT('{"name":"', IFNULL(REPLACE(PG.PROPERTY_GRAPH_NAME, '"', '\"'), ''), '"}') ELSE CONCAT( '{', '"schema_name":"', IFNULL(PG.PROPERTY_GRAPH_SCHEMA, ''), '",', '"object_name":"', IFNULL(PG.PROPERTY_GRAPH_NAME, ''), '",', '"catalog":"', IFNULL(JSON_VALUE(PG.PROPERTY_GRAPH_METADATA_JSON,"$.catalog"), ''), '",', '"node_tables":', TO_JSON_STRING(PG.PROPERTY_GRAPH_METADATA_JSON.nodeTables), ',', '"edge_tables":', TO_JSON_STRING(PG.PROPERTY_GRAPH_METADATA_JSON.edgeTables), ',', '"labels":', TO_JSON_STRING(PG.PROPERTY_GRAPH_METADATA_JSON.labels), ',', '"property_declarations":', TO_JSON_STRING(PG.PROPERTY_GRAPH_METADATA_JSON.propertyDeclarations), '}' ) END AS object_details FROM INFORMATION_SCHEMA.PROPERTY_GRAPHS PG WHERE EXISTS (SELECT 1 FROM FilterGraphNames WHERE FilterGraphNames.GRAPH_NAME = '%') OR PG.PROPERTY_GRAPH_NAME IN (SELECT GRAPH_NAME FROM FilterGraphNames) `