introduce chat api to the project supported by langchain's sql-agent

packages/query/CHANGELOG.md

@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Changed
+- Add LLM and MCP support (#2788)
 
 ## [2.22.1] - 2025-05-21
 ### Changed

packages/query/README.md

@@ -17,3 +17,30 @@ then run the following command
 ```sh
 NODE_OPTIONS="-r dotenv/config" yarn start:dev -- --name <subquery_name> --playground
 ```
+
+## LLM Configuration
+
+Suggest to use reasoning models to archive better quality of results.
+
+### Choose one of the following providers:
+
+### Option 1: OpenAI
+
+LLM_PROVIDER=openai
+LLM_MODEL=o1 # Optional: defaults to '4o-mini'
+OPENAI_API_KEY=your_openai_api_key
+
+### Option 2: Anthropic Claude
+
+LLM_PROVIDER=anthropic
+LLM_MODEL=claude-3-7-sonnet-latest # Optional: defaults to 'claude-3-7-sonnet-latest'
+ANTHROPIC_API_KEY=your_anthropic_api_key
+
+### Option 3: Custom OpenAI-compatible endpoint
+
+LLM_PROVIDER=openai
+LLM_BASE_URL=http://your-llm-endpoint/v1 # Required for custom provider
+LLM_MODEL=your-model-name # Required: model name for custom endpoint
+OPENAI_API_KEY=your_api_key # Optional: API key for custom endpoint
+
+### Common LLM Settings

packages/query/package.json

@@ -35,9 +35,15 @@
     "@graphile-contrib/pg-simplify-inflector": "^6.1.0",
     "@graphile/pg-aggregates": "^0.1.1",
     "@graphile/pg-pubsub": "^4.13.0",
+    "@langchain/anthropic": "^0.3.20",
+    "@langchain/core": "^0.3.55",
+    "@langchain/langgraph": "^0.2.71",
+    "@langchain/openai": "^0.5.10",
+    "@modelcontextprotocol/sdk": "^1.11.5",
     "@nestjs/common": "^9.4.0",
     "@nestjs/core": "^9.4.0",
     "@nestjs/platform-express": "^9.4.0",
+    "@rekog/mcp-nest": "^1.5.2",
     "@subql/common": "workspace:*",
     "@subql/utils": "workspace:*",
     "@subql/x-graphile-build-pg": "4.13.0-0.2.5",
@@ -50,12 +56,14 @@
     "graphql": "^15.8.0",
     "graphql-query-complexity": "^0.11.0",
     "graphql-ws": "^5.16.0",
+    "langchain": "^0.3.24",
     "lodash": "^4.17.21",
     "pg": "^8.12.0",
     "pg-tsquery": "^8.4.2",
     "postgraphile": "^4.13.0",
     "postgraphile-plugin-connection-filter": "^2.2.2",
     "rxjs": "^7.1.0",
+    "typeorm": "^0.3.23",
     "ws": "^8.18.0",
     "yargs": "^16.2.0"
   },

packages/query/src/app.module.ts

@@ -4,9 +4,13 @@
 import {Module} from '@nestjs/common';
 import {ConfigureModule} from './configure/configure.module';
 import {GraphqlModule} from './graphql/graphql.module';
+import {ChatModule} from './llm/chat.module';
+import {MCPModule} from './mcp/mcp.module';
 
 @Module({
-  imports: [ConfigureModule.register(), GraphqlModule],
+  // the order is essential, the ChatModule must be before the GraphqlModule so /v1/chat/completions
+  // can be handled without interference from the GraphqlModule
+  imports: [ConfigureModule.register(), ChatModule, MCPModule, GraphqlModule],
   controllers: [],
 })
 export class AppModule {}

packages/query/src/configure/configure.module.ts

@@ -1,10 +1,11 @@
 // Copyright 2020-2025 SubQuery Pte Ltd authors & contributors
 // SPDX-License-Identifier: GPL-3.0
 
-import {ConnectionOptions} from 'tls';
+import {CommonConnectionOptions, SecureContextOptions} from 'tls';
 import {DynamicModule, Global, Module} from '@nestjs/common';
 import {getFileContent, CONNECTION_SSL_ERROR_REGEX} from '@subql/common';
 import {Pool, PoolConfig} from 'pg';
+import {DataSource} from 'typeorm';
 import {getLogger} from '../utils/logger';
 import {getYargsOption} from '../yargs';
 import {Config} from './config';
@@ -40,7 +41,8 @@ export class ConfigureModule {
     });
 
     const dbSslOption = () => {
-      const sslConfig: ConnectionOptions = {rejectUnauthorized: false};
+      // This is a subset of ConnectionOptions and TlsOptions to satisfy PgPool and DataSource
+      const sslConfig: SecureContextOptions & CommonConnectionOptions = {rejectUnauthorized: false};
       if (opts['pg-ca']) {
         try {
           sslConfig.ca = getFileContent(opts['pg-ca'], 'postgres ca cert');
@@ -85,6 +87,24 @@ export class ConfigureModule {
         pgClient._explainResults = [];
       });
     }
+
+    // Only establish connection if chat is enabled
+    let dataSource: DataSource | undefined;
+    console.log('sslConfig', dbSslOption());
+    if (opts.chat) {
+      dataSource = new DataSource({
+        type: 'postgres',
+        host: config.get('DB_HOST_READ'),
+        port: config.get('DB_PORT'),
+        username: config.get('DB_USER'),
+        password: config.get('DB_PASS'),
+        database: config.get('DB_DATABASE'),
+        schema: config.get<string>('name'),
+        ssl: opts['pg-ca'] ? dbSslOption() : undefined, // Cannot be an empty object
+      });
+      await dataSource.initialize();
+    }
+
     return {
       module: ConfigureModule,
       providers: [
@@ -96,8 +116,12 @@ export class ConfigureModule {
           provide: Pool,
           useValue: pgPool,
         },
+        {
+          provide: DataSource,
+          useValue: dataSource,
+        },
       ],
-      exports: [Config, Pool],
+      exports: [Config, Pool, DataSource],
     };
   }
 }

packages/query/src/graphql/graphql.module.ts

@@ -30,7 +30,6 @@ import {playgroundPlugin} from './plugins/PlaygroundPlugin';
 import {queryAliasLimit} from './plugins/QueryAliasLimitPlugin';
 import {queryComplexityPlugin} from './plugins/QueryComplexityPlugin';
 import {queryDepthLimitPlugin} from './plugins/QueryDepthLimitPlugin';
-import {ProjectService} from './project.service';
 
 const {argv} = getYargsOption();
 const logger = getLogger('graphql-module');
@@ -45,16 +44,15 @@ class NoInitError extends Error {
   }
 }
 @Module({
-  providers: [ProjectService],
+  providers: [],
 })
 export class GraphqlModule implements OnModuleInit, OnModuleDestroy {
   private _apolloServer?: ApolloServer;
   private wsCleanup?: ReturnType<typeof useServer>;
   constructor(
     private readonly httpAdapterHost: HttpAdapterHost,
     private readonly config: Config,
-    private readonly pgPool: Pool,
-    private readonly projectService: ProjectService
+    private readonly pgPool: Pool
   ) {}
 
   private get apolloServer(): ApolloServer {
@@ -138,7 +136,7 @@ export class GraphqlModule implements OnModuleInit, OnModuleDestroy {
     const schemaName = this.config.get<string>('name');
     if (!schemaName) throw new Error('Unable to get schema name from config');
 
-    const dbSchema = await this.projectService.getProjectSchema(schemaName);
+    const dbSchema = schemaName;
     let options: PostGraphileCoreOptions = {
       replaceAllPlugins: plugins,
       subscriptions: true,