Setting Up a CI/CD Pipeline for a NestJS Application Using GitHub Actions

Continuous Integration (CI) and Continuous Deployment (CD) are essential practices in modern software development, allowing teams to automate testing and deployment processes. In this article, we’ll walk through setting up a CI/CD pipeline for a NestJS application using GitHub Actions. We’ll cover definitions, use cases, and provide actionable insights, complete with code examples and step-by-step instructions.

What is CI/CD?

Continuous Integration (CI)

Continuous Integration is the practice of automatically integrating code changes from multiple contributors into a shared repository. This process often involves automated testing to ensure code quality and functionality. The main goal is to detect errors quickly and improve software quality.

Continuous Deployment (CD)

Continuous Deployment takes CI a step further by automatically deploying code changes to production after passing tests. This practice minimizes manual intervention and accelerates the release cycle, allowing teams to deliver features and fixes rapidly.

Why Use CI/CD for NestJS Applications?

NestJS, a progressive Node.js framework, is perfect for building efficient, reliable, and scalable server-side applications. Implementing CI/CD for NestJS applications offers numerous benefits:

• Faster Development: Automate testing and deployment to speed up the development cycle.
• Improved Quality: Catch bugs early through automated tests.
• Consistent Deployments: Reduce human error by automating the deployment process.

Prerequisites

Before diving into the setup, ensure you have the following:

• A NestJS application already set up.
• A GitHub repository to host your code.
• Basic knowledge of Git and GitHub.

Step-by-Step Guide to Setting Up CI/CD with GitHub Actions

Step 1: Create a GitHub Actions Workflow

GitHub Actions uses workflows defined in YAML files located in the .github/workflows directory of your repository. Start by creating a new file named ci-cd-pipeline.yml.

mkdir -p .github/workflows
touch .github/workflows/ci-cd-pipeline.yml

Step 2: Define Your Workflow

Open the ci-cd-pipeline.yml file and define the workflow. Here’s a basic structure to get started:

name: CI/CD Pipeline

on:
  push:
    branches:
      - main
  pull_request:
    branches:
      - main

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v2

      - name: Set up Node.js
        uses: actions/setup-node@v2
        with:
          node-version: '14'

      - name: Install dependencies
        run: npm install

      - name: Run tests
        run: npm test

      - name: Build application
        run: npm run build

Step 3: Configure Testing

In the above workflow, the npm test command runs your tests. Make sure your NestJS application has tests defined. If you haven’t set up testing yet, you can use Jest, which is the default testing framework for NestJS.

To add Jest, install the required packages if you haven’t already:

npm install --save-dev jest @nestjs/testing ts-jest @types/jest

Create a sample test file in your src directory, for example, app.controller.spec.ts:

import { Test, TestingModule } from '@nestjs/testing';
import { AppController } from './app.controller';

describe('AppController', () => {
  let appController: AppController;

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      controllers: [AppController],
    }).compile();

    appController = module.get<AppController>(AppController);
  });

  it('should return "Hello World!"', () => {
    expect(appController.getHello()).toBe('Hello World!');
  });
});

Step 4: Set Up Deployment

After building and testing your application, the next step is to deploy it. You can do this by adding another job in the ci-cd-pipeline.yml file.

  deploy:
    runs-on: ubuntu-latest
    needs: build
    steps:
      - name: Checkout code
        uses: actions/checkout@v2

      - name: Deploy to Server
        run: |
          echo "Deploying to server..."
          # Replace the following line with your actual deployment commands
          # For example, using SSH to connect and deploy
          ssh user@your-server "cd /path/to/app && git pull && npm install && npm run start"

Step 5: Secrets Management

For secure deployment, you should use GitHub Secrets to store sensitive information like server credentials. Go to your GitHub repository settings, find "Secrets," and add your secrets, such as SERVER_USER and SERVER_IP.

You can then reference these secrets in your workflow:

      - name: Deploy to Server
        run: |
          ssh ${{ secrets.SERVER_USER }}@${{ secrets.SERVER_IP }} "cd /path/to/app && git pull && npm install && npm run start"

Step 6: Commit and Push Your Changes

Now, commit your changes and push them to the main branch:

git add .
git commit -m "Setup CI/CD pipeline with GitHub Actions"
git push origin main

Step 7: Monitor Your Pipeline

Once you push your changes, GitHub Actions will automatically trigger the CI/CD pipeline. You can monitor the progress in the "Actions" tab of your GitHub repository.

Troubleshooting Common Issues

• Failed Tests: Check your test configurations and ensure your test files are correctly set up.
• Deployment Failures: Verify SSH access and ensure the deployment commands are correct.
• Environment Variables: Make sure all necessary environment variables are correctly configured in GitHub Secrets.

Conclusion

Setting up a CI/CD pipeline for a NestJS application using GitHub Actions can significantly enhance your development workflow by automating testing and deployment. By following the steps outlined in this article, you’ll not only improve code quality but also accelerate your release cycles.

Embrace the power of CI/CD and propel your NestJS applications to new heights!