CI/CD Pipeline for a Node.js App with Automated Testing and Deployment to Render

This content originally appeared on DEV Community and was authored by Arbythecoder

Introduction

Recently, a friend of mine shared her experience of getting stuck in a difficult loop while trying to set up a CI/CD pipeline for her Node.js application. This sparked the idea for this guide. In this article, we’ll create a professional yet beginner-friendly CI/CD pipeline using GitLab to automate testing and deployment for a simple Node.js application. By the end, you’ll have a robust DevOps workflow to ship code faster and safer.

Folder Structure

node-ci-cd-app/
├── .gitlab-ci.yml          # GitLab pipeline config
├── package.json
├── .gitignore
├── app.js                  # Main server file
├── routes/
│   └── ping.js             # Example route
├── tests/
│   └── ping.test.js        # Test for the ping route
└── README.md

Step 1: Create a Simple Node.js App

1. Initialize Project

Start by setting up your project:

mkdir node-ci-cd-app && cd node-ci-cd-app
npm init -y

2. Install Dependencies

Install the necessary packages:

npm install express
npm install --save-dev jest supertest

3. Create Files

app.js

Create the main server file:

const express = require('express');
const pingRoute = require('./routes/ping');

const app = express();

app.use('/ping', pingRoute);

const PORT = process.env.PORT || 3000;
if (require.main === module) {
  app.listen(PORT, () => console.log(`Server running on port ${PORT}`));
}

module.exports = app;

routes/ping.js

Set up an example route:

const express = require('express');
const router = express.Router();

router.get('/', (req, res) => {
  res.send('pong');
});

module.exports = router;

tests/ping.test.js

Write a test for the ping route:

const request = require('supertest');
const app = require('../app');

describe('GET /ping', () => {
  it('should return pong', async () => {
    const res = await request(app).get('/ping');
    expect(res.statusCode).toBe(200);
    expect(res.text).toBe('pong');
  });
});

.gitignore

Create a .gitignore file to exclude unnecessary files:

node_modules
.env

package.json (scripts section)

Update the scripts section in your package.json:

"scripts": {
  "start": "node app.js",
  "test": "jest"
}

You can now run:

node app.js         # Start server
npm test            # Run tests

Step 2: Push to GitLab & Add CI/CD Pipeline

1. Create a New GitLab Repo

• Go to GitLab
• Click “New Project” > “Create blank project”
• Name it node-ci-cd-app
• Click “Create Project”

2. Connect Local Repo

Run these commands in your terminal:

git init
git remote add origin https://gitlab.com/your-username/node-ci-cd-app.git
git config --global user.name "Your Name"
git config --global user.email "you@example.com"
git add .
git commit -m "Initial commit"
git branch -M main
git push -u origin main

If you encounter the error: error: src refspec main does not match any, it means the main branch does not exist yet. Simply run:

git branch -M main

Then try pushing again:

git push -u origin main

3. Add .gitlab-ci.yml

Create a .gitlab-ci.yml file in your root directory with the following content:

stages:
  - test

run_tests:
  stage: test
  image: node:18
  script:
    - npm install
    - npm test

4. Push to Trigger Pipeline

Add the CI/CD configuration file to your repository:

git add .gitlab-ci.yml
git commit -m "Add CI pipeline for testing"
git push

5. Monitor on GitLab

• Go to CI/CD > Pipelines in your GitLab project.
• Check the pipeline status and job logs to ensure everything is running smoothly.

Step 3: Deploy to Render (Coming Up)

In the next section, we will:

• Deploy the Node.js app to Render using Deploy Hooks.
• Secure secrets with GitLab CI/CD Variables.
• Add a deploy stage to our pipeline.

Stay tuned for the next part!

This content originally appeared on DEV Community and was authored by Arbythecoder