code update recorded at: 13/01/25 11:04:31

handler.js

@@ -0,0 +1,217 @@
+import mysql from 'mysql2/promise';
+import { createTunnel } from 'tunnel-ssh';
+
+// Maximum allowed connections in the connection pool
+const MAX_CONNECTIONS = parseInt(process.env.MAX_CONNECTIONS || '10');
+// Connection pool to manage database connections
+const connectionPool = new Map();
+// Timeout for MySQL connections, configurable via environment variables
+const CONNECTION_TIMEOUT = parseInt(process.env.CONNECTION_TIMEOUT || '10000');
+
+/**
+ * Validates the request body for required fields and structure.
+ * Ensures all necessary fields for MySQL and SSH configurations are provided.
+ * @param {Object} body - Request body containing query and secretData.
+ * @throws {Error} If validation fails.
+ */
+const validateRequestBody = ({ query, secretData }) => {
+  const errors = [];
+
+  // Ensure the query string is provided
+  if (!query) {
+    errors.push('Query is required.');
+  }
+
+  // Validate database configuration
+  const { db_config, ssh_config, use_ssh } = secretData || {};
+  if (!db_config) {
+    errors.push('secretData.db_config is required.');
+  }
+
+  const { hosts, database, username, password } = db_config || {};
+  if (!hosts || hosts.length === 0) errors.push('db_config.hosts is required.');
+  if (!database) errors.push('db_config.database is required.');
+  if (!username) errors.push('db_config.username is required.');
+  if (!password) errors.push('db_config.password is required.');
+
+  // Validate SSH configuration if required
+  if (use_ssh) {
+    if (!ssh_config) {
+      errors.push('secretData.ssh_config is required when use_ssh is true.');
+    } else {
+      const { host, port, username, private_key_file, auth_method } = ssh_config || {};
+      if (!host) errors.push('ssh_config.host is required.');
+      if (!port) errors.push('ssh_config.port is required.');
+      if (!username) errors.push('ssh_config.username is required.');
+      if (auth_method === 'private_key' && !private_key_file) {
+        errors.push('ssh_config.private_key_file is required for private_key auth.');
+      }
+    }
+  }
+
+  // Throw error if any validation fails
+  if (errors.length) {
+    var msg = `Validation errors: ${errors.join(' ')}`
+    console.log(msg)
+    throw new Error(msg);
+  }
+};
+
+/**
+ * Creates a MySQL connection with a timeout for connection attempts.
+ * @param {Object} config - Configuration for MySQL.
+ * @param {number} [localPort=null] - Local port for SSH tunneling.
+ * @returns {Promise<Client>} The MySQL client instance.
+ */
+const createMySQLConnection = async (config, localPort = null) => {
+  const { use_ssh } = config.secretData;
+  const { username, password, hosts, database } = config.secretData.db_config;
+
+  const connectionHost = use_ssh ? '127.0.0.1' : hosts[0]?.host;
+  const connectionPort = use_ssh ? localPort : hosts[0]?.port || 5432;
+
+  console.log(`Connecting to MySQL URI: mysql://<REDACTED>:<REDACTED>@${connectionHost}:${connectionPort}/${database}`);
+
+  try {
+    // Attempt to connect to MySQL within the defined timeout
+    const client = await mysql.createConnection({
+      host: connectionHost,
+      port: connectionPort,
+      user: username,
+      password: password,
+      database: database,
+      connectTimeout: CONNECTION_TIMEOUT,
+    });
+
+    console.log('MySQL connection successful');
+    return client;
+  } catch (error) {
+    console.error(`MySQL connection failed: ${error.message}`);
+    throw error;
+  }
+};
+
+/**
+ * Establishes an SSH tunnel for secure database connections.
+ * Provides port forwarding from a local port to the remote database server.
+ * @param {Object} sshConfig - SSH configuration.
+ * @param {string} dbHost - Database host.
+ * @param {number} dbPort - Database port.
+ * @returns {Promise<Object>} The SSH tunnel and local port.
+ */
+const createSSHTunnel = async (sshConfig, dbHost, dbPort) => {
+  try {
+    const { host, port, username, private_key_file, auth_method } = sshConfig;
+    const tunnelOptions = { autoClose: true };
+    const forwardOptions = { dstAddr: dbHost, dstPort: dbPort };
+    const sshOptions = {
+      host,
+      port,
+      username,
+      privateKey: auth_method === 'private_key' ? Buffer.from(private_key_file, 'utf-8') : undefined,
+    };
+
+    const [server, conn] = await createTunnel(tunnelOptions, null, sshOptions, forwardOptions);
+    const localPort = server.address().port;
+    console.log(`SSH tunnel established. Local port: ${localPort}`);
+
+    // Attach error listeners to the SSH server and connection
+    server.on('error', (err) => {
+      throw new Error(`SSH Tunnel Server Error: ${err.message}`);
+    });
+    conn.on('error', (err) => {
+      throw new Error(`SSH Tunnel Connection Error: ${err.message}`);
+    });
+
+    return { tunnel: server, localPort };
+  } catch (err) {
+    console.error(`Failed to establish SSH tunnel: ${err.message}`);
+    throw err;
+  }
+};
+
+/**
+ * Retrieves an existing connection or creates a new one if not available.
+ * Ensures that the number of active connections does not exceed the allowed limit.
+ * @param {Object} config - Configuration for the connection.
+ * @param {string} query - MySQL query to execute.
+ * @returns {Promise<Client>} The MySQL client instance.
+ */
+const getOrCreateConnection = async (config, query) => {
+  const configKey = JSON.stringify(config);
+
+  // Return existing connection if available
+  if (connectionPool.has(configKey)) {
+    return connectionPool.get(configKey);
+  }
+
+  // Check if connection pool has reached its limit
+  if (connectionPool.size >= MAX_CONNECTIONS) {
+    throw new Error('Connection limit reached.');
+  }
+
+  const { use_ssh, db_config, ssh_config } = config.secretData;
+
+  try {
+    // Create a new connection, either with or without SSH
+    const connection = use_ssh
+      ? await (async () => {
+        const { host: dbHost, port: dbPort } = db_config.hosts[0];
+        const { tunnel, localPort } = await createSSHTunnel(ssh_config, dbHost, dbPort);
+        const mySQLConnection = await createMySQLConnection(config, localPort);
+        mySQLConnection._tunnel = tunnel; // Store tunnel instance for cleanup
+        return mySQLConnection;
+      })()
+      : await createMySQLConnection(config);
+
+    // Cache the newly created connection
+    connectionPool.set(configKey, connection);
+    return connection;
+  } catch (error) {
+    console.error('Error creating connection:', error.message);
+    throw error;
+  }
+};
+
+/**
+ * Express.js handler for incoming requests.
+ * Processes MySQL queries based on provided configurations and query string.
+ * @param {Object} req - Express request object.
+ * @param {Object} res - Express response object.
+ */
+export const handler = async (req, res) => {
+  try {
+    // Ensure the request method is POST
+    if (req.method !== 'POST') {
+      return res.status(400).json({ error: 'Invalid method, only POST allowed.' });
+    }
+
+    // Extract and validate request body
+    const body = req.body;
+    validateRequestBody(body);
+
+    const { query, secretData } = body;
+    const client = await getOrCreateConnection({ secretData }, query);
+
+    // Execute the provided query in the MySQL instance
+    var data = [];
+    const [rows] = await client.execute(query);
+
+    // Return rows for SELECT queries
+    if (rows && rows.length > 0) {
+      data = rows;
+    } else if (rows && 'affectedRows' in rows) { // For write queries (INSERT, UPDATE, DELETE), check affected rows
+      data = {
+        affectedRows: rows.affectedRows || 0,
+        message: rows.info || 'Query executed successfully',
+      };
+    }
+
+    console.log('Query executed successfully:', JSON.stringify(data));
+    res.setHeader('Content-Type', 'application/json');
+    res.status(200).json(data);
+  } catch (error) {
+    console.error('Error handling request:', error.message);
+    res.status(500).json({ error: error.message });
+  }
+};

package.json

@@ -0,0 +1,19 @@
+{
+    "name": "boltic-mysql-connector",
+    "version": "1.0.0",
+    "description": "The MySQL connector enables seamless integration with any MySQL database, allowing you to perform various operations efficiently.",
+    "main": "handler.js",
+    "scripts": {
+        "start": "node handler.js"
+    },
+    "dependencies": {
+        "mysql2": "^3.12.0",
+        "tunnel-ssh": "^5.1.2"
+    },
+    "engines": {
+        "node": ">=16.0.0"
+    },
+    "author": "Your Name",
+    "license": "MIT",
+    "type": "module"
+}