From 0149ca960bdf4c94e76f25e5826f296421f6858f Mon Sep 17 00:00:00 2001 From: Sameer Dev Date: Mon, 13 Jan 2025 08:07:25 +0000 Subject: [PATCH] code update recorded at: 13/01/25 08:07:25 --- handler.js | 217 +++++++++++++++++++++++++++++++++++++++++++++++++++ package.json | 19 +++++ 2 files changed, 236 insertions(+) create mode 100644 handler.js create mode 100644 package.json diff --git a/handler.js b/handler.js new file mode 100644 index 0000000..a9b51d8 --- /dev/null +++ b/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: ${errors.join(' ')}` + console.log(msg) + throw new Error(msg); + } +}; + +/** + * Creates a MySQL connection with a timeout for connection attempts. + * @param {Object} config - Configuration for MySQL. + * @param {number} [localPort=null] - Local port for SSH tunneling. + * @returns {Promise} The MySQL client instance. + */ +const createMySQLConnection = async (config, localPort = null) => { + const { use_ssh } = config.secretData; + const { username, password, hosts, database } = config.secretData.db_config; + + const connectionHost = use_ssh ? '127.0.0.1' : hosts[0]?.host; + const connectionPort = use_ssh ? localPort : hosts[0]?.port || 5432; + + console.log(`Connecting to MySQL URI: mysql://:@${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} 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} 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 }); + } +}; diff --git a/package.json b/package.json new file mode 100644 index 0000000..2d6111e --- /dev/null +++ b/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" +}