Check if Node.js MySQL Server is Active or Not

To check if a MySQL server is active or not from a Node.js application, you typically want to establish a connection to the MySQL server and handle any errors that occur during the connection attempt. Here’s a step-by-step guide on how to achieve this.

Prerequisites:

• NodeJS
• ExpressJS
• MySQL

Approach

To check if a Node.js MySQL server is active, use the mysql package to create a connection and call database_connection.ping(callback) to verify the server status in the callback function.

Syntax:

database_connection.ping(callback);

Installation Steps

Step 1: Make a folder structure for the project.

mkdir myapp

Step 2: Navigate to the project directory

cd myapp

Step 3: Initialize the NodeJs project inside the myapp folder.

npm init -y

Step 4: Install the required dependencies by the following command:

npm install express
npm install mysql

The updated dependencies in package.json file will look like:

"dependencies": {
   "express": "^4.15.4",
   "mysql": "^2.18.1",
  }

Example: Implementation to create server first and also create and export database connection object.

Node

// sqlConnection.js

const mysql = require("mysql");

let db_con  = mysql.createConnection({
    host: "localhost",
    user: "root",
    password: ''
});

db_con.connect((err) => {
    if (err) {
      console.log("Database Connection Failed !!!", err);
    } else {
      console.log("connected to Database");
    }
});

module.exports = db_con;

// app.js

const express = require("express");
const database = require('./sqlConnection');

const app = express();

app.listen(5000, () => {
  console.log(`Server is up and running on 5000 ...`);
});

app.get("/getMysqlStatus", (req, res) => {
    
    // Create Route to Check mysql server Active or Not.
    
    database.ping((err) => {
        if(err) return res.status(500).send("MySQL Server is Down");
        
        res.send("MySQL Server is Active");
    })
});

Step to Run Application: Run the application using the following command from the root directory of the project

node app.js

Output: Put this link in your browser http://localhost:5000/getMysqlStatus , If server is Not Active you will see below output in your browser

MySQL Server is Down

MySQL Server is Active

If server is Active you will see below output in your browser:

Additional Considerations

• Error Handling: Always handle connection errors to gracefully manage server unavailability or configuration issues.
• Connection Pooling: For production applications, consider using connection pooling (mysql2 supports this) to efficiently manage database connections.
• Environment Variables: Store sensitive database credentials (like passwords) in environment variables and access them securely in your Node.js application.
• Monitoring: Implement health checks or monitoring solutions to continuously monitor the status of your MySQL server.

Conclusion

Checking if a MySQL server is active from a Node.js application involves establishing a connection and handling connection errors. By following the steps outlined above and using appropriate error handling techniques, you can ensure that your application can reliably connect to and interact with MySQL databases.