Can't connect Node.js app from Droplet to mySQL database in managed db cluster

Hello,

For a few days now I have been trying to set up a droplet with a mysql Database on a managed DB cluster (also on DigitalOcean), but have been running into trouble getting the app connected to the database: I keep getting the connection timed out error, which the docs refer to as a firewall (db-side) issue.

/home/nodejs/.pm2/logs/app-error.log last 15 lines:

0|app      |     at process.processTimers (node:internal/timers:507:7) {

0|app      |   errorno: 'ETIMEDOUT',

0|app      |   code: 'ETIMEDOUT',

0|app      |   syscall: 'connect',

0|app      |   fatal: true

0|app      | }

0|app      | Error: connect ETIMEDOUT

0|app      |     at PoolConnection._handleTimeoutError (/var/www/html/project-root/node_modules/mysql2/lib/connection.js:205:17)

0|app      |     at listOnTimeout (node:internal/timers:564:17)

0|app      |     at process.processTimers (node:internal/timers:507:7) {

0|app      |   errorno: 'ETIMEDOUT',

0|app      |   code: 'ETIMEDOUT',

0|app      |   syscall: 'connect',

0|app      |   fatal: true

0|app      | }

The set-up is as follows:

• The app is currently running on node v16.20.2, which is deprecated, but will be updated later, once I get it running.
• I am using pm2 as a process runner, but get the same issue when I directly run the app without pm2
• I am using mysql2 to create a DB pool connecting to the database, with the connection details coming from the .env file
• I downloaded the ca-certificate.crt from the Database connection info window
• The droplet using ufw, with all necessary ports allowed
• I whitelisted the droplet, the VPC IP&Range, the private IP of the droplet in the database, but also tried whitelisting various 127.0.. after checking hostname -i inside the droplets ssh console
• I am able to directly connect to the database via the console with a mysql command, just not from the node.js app

This is the setup for the dbPool connect:

const mysql = require('mysql2');

const fs = require('fs');

const path = require('path');



const caCertPath = path.join(__dirname, '../../config/ca-certificate.crt');

const caCert = fs.readFileSync(caCertPath);



const dbPool = mysql.createPool({

    connectionLimit: 100,

    host: process.env.DB_HOST,

    user: process.env.DB_USER,

    password: process.env.DB_PASSWORD,

    database: process.env.DB_DATABASE,

    multipleStatements: true,

    ssl: {

        ca: caCert

    }

});



module.exports = dbPool;

The ca certificate is in /project-root/config/ca-certificate.crt while the dbConnect.js is inside /project-root/backend/utils/dbConnect.js

And inside the app.js:

**// Import module**

const dbPool = require('./backend/utils/dbConnect');



**// Connect db**

dbPool.getConnection((err, connection) => {

console.log('err connent', err);

    if (err) throw (err); **// If not connected**

    console.log('Connected to mySQL as ID ' + connection.threadId);

});

And the .env file:

DB_HOST='db-mysql-****-*****-do-user-********-0.c.db.ondigitalocean.com'

DB_USER='username'

DB_PASSWORD='password'

DB_DATABASE='dbname'

DB_PORT='25060'

I also tried various ports for the DB Port, like 25061 and 3306. When I use localhost or 127.0.0.1 or variations of that, I get a handshake error issue:

0|app  | Listening on port 3000

0|app  | err connent Error: self-signed certificate in certificate chain

0|app  |     at TLSSocket.onConnectSecure (node:_tls_wrap:1538:34)

0|app  |     at TLSSocket.emit (node:events:513:28)

0|app  |     at TLSSocket._finishInit (node:_tls_wrap:952:8)

0|app  |     at ssl.onhandshakedone (node:_tls_wrap:733:12) {

0|app  |   code: 'HANDSHAKE_SSL_ERROR',

0|app  |   fatal: true

0|app  | }

I also tried setting up a managed app with node.js and a deployment process with the github repository with a DB added to the App during the app creation process in the digital ocean backend and tried the existing managed DB cluster database and run into 1:1 the same issues.

Could someone point me into the right directions to solve this issue?

Thank you very much, Julian