feat: add MySQL Unix socket support and fix build errors

- Add support for Unix socket connections via MYSQL_SOCKET_PATH env var
- Automatically detect and use socket connection when MYSQL_SOCKET_PATH is set
- Fix TypeScript build errors caused by duplicate variable declarations in evals.ts
- Update documentation with Unix socket example
- Add integration tests for Unix socket connections
- Update Smithery configuration to support socket connections
- Maintain backward compatibility with existing TCP/IP connections

Handles designcomputer#37, Fixes designcomputer#46

Author: elvismdev

.env.dist

@@ -1,5 +1,6 @@
 # Basic MySQL connection settings
 MYSQL_HOST=127.0.0.1
+MYSQL_SOCKET_PATH=/tmp/mysql.sock
 MYSQL_PORT=3306
 MYSQL_USER=root
 MYSQL_PASS=your_password

.env.test

@@ -1,4 +1,5 @@
 MYSQL_HOST=127.0.0.1
+MYSQL_SOCKET_PATH=/tmp/mysql.sock
 MYSQL_PORT=3306
 MYSQL_USER=root
 MYSQL_PASS=root

README.md

@@ -347,8 +347,9 @@ For more control over the MCP server's behavior, you can use these advanced conf
 ## Environment Variables
 
 ### Basic Connection
-- `MYSQL_HOST`: MySQL server host (default: "127.0.0.1")
-- `MYSQL_PORT`: MySQL server port (default: "3306")
+- `MYSQL_SOCKET_PATH`: Unix socket path for local connections (e.g., "/tmp/mysql.sock")
+- `MYSQL_HOST`: MySQL server host (default: "127.0.0.1") - ignored if MYSQL_SOCKET_PATH is set
+- `MYSQL_PORT`: MySQL server port (default: "3306") - ignored if MYSQL_SOCKET_PATH is set
 - `MYSQL_USER`: MySQL username (default: "root")
 - `MYSQL_PASS`: MySQL password
 - `MYSQL_DB`: Target database name (leave empty for multi-DB mode)

evals.ts

@@ -4,7 +4,7 @@ import { EvalConfig } from 'mcp-evals';
 import { openai } from "@ai-sdk/openai";
 import { grade, EvalFunction } from "mcp-evals";
 
-const mysql_queryEval: EvalFunction = {
+const mysqlQueryToolEval: EvalFunction = {
     name: 'mysql_query Tool Evaluation',
     description: 'Evaluates the MySQL query execution functionality',
     run: async () => {
@@ -13,18 +13,18 @@ const mysql_queryEval: EvalFunction = {
     }
 };
 
-const mysql_queryEval: EvalFunction = {
-    name: 'mysql_query Tool Evaluation',
+const mysqlQueryGenerationEval: EvalFunction = {
+    name: 'mysql_query Tool Generation Evaluation',
     description: 'Evaluates the MySQL query tool for correct SQL generation and execution',
     run: async () => {
         const result = await grade(openai("gpt-4"), "Use the mysql_query tool to select all rows from the 'users' table where isActive = 1. Provide the SQL query in the correct format.");
         return JSON.parse(result);
     }
 };
 
-const mysql_queryEval: EvalFunction = {
-    name: 'mysql_queryEval',
-    description: 'Evaluates the mysql_query tool',
+const mysqlQueryColumnsEval: EvalFunction = {
+    name: 'mysql_query Columns Evaluation',
+    description: 'Evaluates the mysql_query tool for column selection',
     run: async () => {
         const result = await grade(openai("gpt-4"), "Please provide a SQL query to retrieve the id, name, and email columns for all records in the users table.");
         return JSON.parse(result);
@@ -33,9 +33,9 @@ const mysql_queryEval: EvalFunction = {
 
 const config: EvalConfig = {
     model: openai("gpt-4"),
-    evals: [mysql_queryEval, mysql_queryEval, mysql_queryEval]
+    evals: [mysqlQueryToolEval, mysqlQueryGenerationEval, mysqlQueryColumnsEval]
 };
 
 export default config;
 
-export const evals = [mysql_queryEval, mysql_queryEval, mysql_queryEval];
+export const evals = [mysqlQueryToolEval, mysqlQueryGenerationEval, mysqlQueryColumnsEval];

index.ts

@@ -197,16 +197,24 @@ if (ALLOW_INSERT_OPERATION || ALLOW_UPDATE_OPERATION || ALLOW_DELETE_OPERATION |
   toolDescription += ' (READ-ONLY)'
 }
 
-// Update MySQL config to handle blank database name
+// Update MySQL config to handle blank database name and Unix socket connections
 const config = {
   server: {
     name: '@benborla29/mcp-server-mysql',
     version: '0.1.18',
     connectionTypes: ['stdio'],
   },
   mysql: {
-    host: process.env.MYSQL_HOST || '127.0.0.1',
-    port: Number(process.env.MYSQL_PORT || '3306'),
+    // Use Unix socket if provided, otherwise use host/port
+    ...(process.env.MYSQL_SOCKET_PATH
+      ? {
+          socketPath: process.env.MYSQL_SOCKET_PATH,
+        }
+      : {
+          host: process.env.MYSQL_HOST || '127.0.0.1',
+          port: Number(process.env.MYSQL_PORT || '3306'),
+        }
+    ),
     user: process.env.MYSQL_USER || 'root',
     password: process.env.MYSQL_PASS || 'root',
     database: process.env.MYSQL_DB || undefined, // Allow undefined database for multi-DB mode
@@ -232,8 +240,17 @@ const config = {
 // @INFO: Add debug logging for configuration
 log('info', 'MySQL Configuration:', JSON.stringify(
   {
-    host: config.mysql.host,
-    port: config.mysql.port,
+    ...(process.env.MYSQL_SOCKET_PATH
+      ? {
+          socketPath: process.env.MYSQL_SOCKET_PATH,
+          connectionType: 'Unix Socket',
+        }
+      : {
+          host: process.env.MYSQL_HOST || '127.0.0.1',
+          port: process.env.MYSQL_PORT || '3306',
+          connectionType: 'TCP/IP',
+        }
+    ),
     user: config.mysql.user,
     password: config.mysql.password ? '******' : 'not set',
     database: config.mysql.database || 'MULTI_DB_MODE',
@@ -294,6 +311,11 @@ const getServer = (): Promise<Server> => {
         async () => {
           try {
             log('error', 'Handling ListResourcesRequest')
+
+            // Determine connection info for URI
+            const connectionInfo = process.env.MYSQL_SOCKET_PATH 
+            ? `socket:${process.env.MYSQL_SOCKET_PATH}`
+            : `${process.env.MYSQL_HOST || '127.0.0.1'}:${process.env.MYSQL_PORT || '3306'}`;
 
             // If we're in multi-DB mode, list all databases first
             if (isMultiDbMode) {
@@ -317,7 +339,7 @@ const getServer = (): Promise<Server> => {
                 allResources.push(...tables.map((row: TableRow) => ({
                   uri: new URL(
                     `${db.Database}/${row.table_name}/${config.paths.schema}`,
-                    `${config.mysql.host}:${config.mysql.port}`,
+                    connectionInfo,
                   ).href,
                   mimeType: 'application/json',
                   name: `"${db.Database}.${row.table_name}" database schema`,
@@ -337,7 +359,7 @@ const getServer = (): Promise<Server> => {
                 resources: results.map((row: TableRow) => ({
                   uri: new URL(
                     `${row.table_name}/${config.paths.schema}`,
-                    `${config.mysql.host}:${config.mysql.port}`,
+                    connectionInfo,
                   ).href,
                   mimeType: 'application/json',
                   name: `"${row.table_name}" database schema`,

package-lock.json

@@ -21,9 +21,10 @@
     "build": "tsc && shx chmod +x dist/*.js",
     "prepare": "npm run build",
     "watch": "tsc --watch",
-    "setup:test:db": "node --loader ts-node/esm scripts/setup-test-db.ts",
+    "setup:test:db": "tsx scripts/setup-test-db.ts",
     "pretest": "pnpm run setup:test:db",
     "test": "pnpm run setup:test:db && vitest run",
+    "test:socket": "pnpm run setup:test:db && vitest run tests/integration/socket-connection.test.ts",
     "test:watch": "pnpm run setup:test:db && vitest",
     "test:coverage": "vitest run --coverage",
     "test:unit": "vitest run --config vitest.unit.config.ts",
@@ -46,6 +47,7 @@
     "shx": "^0.3.4",
     "ts-node": "^10.9.2",
     "tslib": "^2.8.1",
+    "tsx": "^4.19.4",
     "typescript": "^5.8.2",
     "vitest": "^1.6.1"
   },

package.json

@@ -32,8 +32,16 @@ function log(type: LogType = 'info', ...args: any[]): void {
 async function setupTestDatabase() {
   // Create connection config, omitting password if empty
   const config: any = {
-    host: process.env.MYSQL_HOST || '127.0.0.1',
-    port: Number(process.env.MYSQL_PORT) || 3306,
+    // Use Unix socket if provided, otherwise use host/port
+    ...(process.env.MYSQL_SOCKET_PATH
+      ? {
+          socketPath: process.env.MYSQL_SOCKET_PATH,
+        }
+      : {
+          host: process.env.MYSQL_HOST || '127.0.0.1',
+          port: Number(process.env.MYSQL_PORT) || 3306,
+        }
+    ),
     user: process.env.MYSQL_USER || 'root',
     password: process.env.MYSQL_PASS || 'root', // Default to 'root' if not specified
     multipleStatements: true

scripts/setup-test-db.ts

@@ -4,18 +4,18 @@ startCommand:
   configSchema:
     # JSON Schema defining the configuration options for the MCP.
     type: object
-    required:
-      - mysqlHost
-      - mysqlPort
-      - mysqlUser
+    required: []
     properties:
+      mysqlSocketPath:
+        type: string
+        description: Unix socket path for local MySQL connections. If provided, host and port are ignored.
       mysqlHost:
         type: string
-        description: The host address of the MySQL database.
+        description: The host address of the MySQL database. Ignored if socket path is provided.
         default: "127.0.0.1"
       mysqlPort:
         type: string
-        description: The port number for connecting to MySQL.
+        description: The port number for connecting to MySQL. Ignored if socket path is provided.
         default: "3306"
       mysqlUser:
         type: string
@@ -50,4 +50,4 @@ startCommand:
         description: If set to true, DELETE operations will be allowed.
     commandFunction:
       |-
-      (config) => ({ "command": "node", "args": ["dist/index.js"], "env": { "MYSQL_HOST": config.mysqlHost, "MYSQL_PORT": config.mysqlPort, "MYSQL_USER": config.mysqlUser, "MYSQL_PASS": config.mysqlPass, "MYSQL_DB": config.mysqlDb, "MYSQL_SSL": config.ssl, "MYSQL_SSL_REJECT_UNAUTHORIZED": config.rejectUnauthorizedSSL, "ALLOW_INSERT_OPERATION": config.allowInsertOperation, "ALLOW_UPDATE_OPERATION": config.allowUpdateOperation, "ALLOW_DELETE_OPERATION": config.allowDeleteOperation } })
+      (config) => ({ "command": "node", "args": ["dist/index.js"], "env": { "MYSQL_SOCKET_PATH": config.mysqlSocketPath, "MYSQL_HOST": config.mysqlHost, "MYSQL_PORT": config.mysqlPort, "MYSQL_USER": config.mysqlUser, "MYSQL_PASS": config.mysqlPass, "MYSQL_DB": config.mysqlDb, "MYSQL_SSL": config.ssl, "MYSQL_SSL_REJECT_UNAUTHORIZED": config.rejectUnauthorizedSSL, "ALLOW_INSERT_OPERATION": config.allowInsertOperation, "ALLOW_UPDATE_OPERATION": config.allowUpdateOperation, "ALLOW_DELETE_OPERATION": config.allowDeleteOperation } })

smithery.yaml

@@ -0,0 +1,88 @@
+import * as mysql2 from 'mysql2/promise';
+import { describe, it, expect, beforeAll, afterAll } from 'vitest';
+import * as dotenv from 'dotenv';
+import * as path from 'path';
+import { fileURLToPath } from 'url';
+
+// Set test directory path
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+// Load test environment variables
+dotenv.config({ path: path.resolve(__dirname, '../../.env.test') });
+
+describe('Unix Socket Connection', () => {
+  // Skip these tests if no socket path is provided
+  const skipTests = !process.env.MYSQL_SOCKET_PATH;
+  
+  it.skipIf(skipTests)('should connect via Unix socket when MYSQL_SOCKET_PATH is set', async () => {
+    const originalHost = process.env.MYSQL_HOST;
+    const originalPort = process.env.MYSQL_PORT;
+    const originalSocketPath = process.env.MYSQL_SOCKET_PATH;
+    
+    try {
+      // Set socket path (use the actual socket path from environment or a test path)
+      process.env.MYSQL_SOCKET_PATH = originalSocketPath || '/tmp/mysql.sock';
+      delete process.env.MYSQL_HOST;
+      delete process.env.MYSQL_PORT;
+      
+      // Create a connection pool using socket
+      const config: any = {
+        socketPath: process.env.MYSQL_SOCKET_PATH,
+        user: process.env.MYSQL_USER || 'root',
+        database: process.env.MYSQL_DB || 'mcp_test',
+        connectionLimit: 5,
+      };
+      
+      // Only add password if it's set
+      if (process.env.MYSQL_PASS) {
+        config.password = process.env.MYSQL_PASS;
+      }
+      
+      const pool = mysql2.createPool(config);
+      
+      // Test the connection
+      const connection = await pool.getConnection();
+      expect(connection).toBeDefined();
+      
+      // Execute a simple query
+      const [rows] = await connection.query('SELECT 1 as test') as [any[], any];
+      expect(rows[0].test).toBe(1);
+      
+      connection.release();
+      await pool.end();
+    } finally {
+      // Restore original values
+      if (originalHost) process.env.MYSQL_HOST = originalHost;
+      if (originalPort) process.env.MYSQL_PORT = originalPort;
+      if (originalSocketPath) process.env.MYSQL_SOCKET_PATH = originalSocketPath;
+      else delete process.env.MYSQL_SOCKET_PATH;
+    }
+  });
+  
+  it('should prefer socket path over host/port when both are provided', async () => {
+    // This test verifies the configuration logic
+    const mockConfig = {
+      ...(process.env.MYSQL_SOCKET_PATH
+        ? {
+            socketPath: process.env.MYSQL_SOCKET_PATH,
+          }
+        : {
+            host: process.env.MYSQL_HOST || '127.0.0.1',
+            port: Number(process.env.MYSQL_PORT || '3306'),
+          }
+      ),
+    };
+    
+    // If socket path is set, config should not have host/port
+    if (process.env.MYSQL_SOCKET_PATH) {
+      expect(mockConfig).toHaveProperty('socketPath');
+      expect(mockConfig).not.toHaveProperty('host');
+      expect(mockConfig).not.toHaveProperty('port');
+    } else {
+      expect(mockConfig).not.toHaveProperty('socketPath');
+      expect(mockConfig).toHaveProperty('host');
+      expect(mockConfig).toHaveProperty('port');
+    }
+  });
+});