WikiGalaxy
Setting up CI/CD for Node.js Apps
Continuous Integration (CI)
Continuous Integration is a software development practice where developers regularly merge their code changes into a central repository, followed by automated builds and tests. This process helps in identifying bugs early in the development lifecycle, improving the overall quality of the software.
Continuous Deployment (CD)
Continuous Deployment is a strategy that ensures that every change that passes all stages of the production pipeline is released to customers. This approach allows for frequent updates and improvements, ensuring that the application is always in a deployable state.
Benefits of CI/CD for Node.js Apps
- Faster delivery of features and fixes.
- Improved collaboration among team members.
- Reduced risk of deployment failures.
- Higher quality software with fewer bugs.
Tools for CI/CD
Several tools can be used to implement CI/CD pipelines for Node.js applications, including Jenkins, Travis CI, CircleCI, GitHub Actions, and GitLab CI/CD.
Setting Up a CI/CD Pipeline
To set up a CI/CD pipeline for a Node.js application, you need to define the stages of your pipeline, configure your CI/CD tool, and write scripts to automate the build, test, and deployment processes.
Example: Setting Up CI with GitHub Actions
GitHub Actions Workflow
GitHub Actions allows you to automate tasks within your software development lifecycle. You can create workflows that build, test, package, release, and deploy your code right from GitHub.
# .github/workflows/nodejs.yml
name: Node.js CI
on:
push:
branches: [ main ]
pull_request:
branches: [ main ]
jobs:
build:
runs-on: ubuntu-latest
strategy:
matrix:
node-version: [12.x, 14.x, 16.x]
steps:
- uses: actions/checkout@v2
- name: Use Node.js ${{ matrix.node-version }}
uses: actions/setup-node@v2
with:
node-version: ${{ matrix.node-version }}
- run: npm install
- run: npm test
Explanation
This GitHub Actions workflow is triggered on pushes and pull requests to the main branch. It runs on Ubuntu and tests the application using different Node.js versions (12.x, 14.x, 16.x). The workflow includes steps to check out the code, set up Node.js, install dependencies, and run tests.
Example: Deploying with Heroku
Heroku Deployment
Heroku is a platform as a service (PaaS) that enables developers to build, run, and operate applications entirely in the cloud.
# .github/workflows/deploy.yml
name: Deploy to Heroku
on:
push:
branches: [ main ]
jobs:
deploy:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v2
- name: Deploy to Heroku
env:
HEROKU_API_KEY: ${{ secrets.HEROKU_API_KEY }}
run: |
git remote add heroku https://git.heroku.com/YOUR_APP_NAME.git
git push heroku main
Explanation
This workflow deploys the application to Heroku whenever there is a push to the main branch. It uses the Heroku API key stored in GitHub secrets to authenticate and deploy the application.
Example: Continuous Deployment with Jenkins
Jenkins Pipeline
Jenkins is an open-source automation server that enables developers to build, test, and deploy their software.
pipeline {
agent any
stages {
stage('Build') {
steps {
sh 'npm install'
}
}
stage('Test') {
steps {
sh 'npm test'
}
}
stage('Deploy') {
steps {
sh 'npm run deploy'
}
}
}
}
Explanation
This Jenkins pipeline script automates the build, test, and deployment stages of a Node.js application. It uses shell commands to run npm scripts for each stage.
Example: Dockerizing a Node.js App
Docker Setup
Docker allows you to package an application and its dependencies into a container, which can be run consistently on any environment.
# Dockerfile
FROM node:14
WORKDIR /usr/src/app
COPY package*.json ./
RUN npm install
COPY . .
EXPOSE 8080
CMD [ "node", "server.js" ]
Explanation
This Dockerfile sets up a Node.js application to run in a Docker container. It specifies the base image, working directory, copies the application files, installs dependencies, exposes a port, and defines the command to start the application.
Example: Testing with Mocha and Chai
Mocha and Chai Setup
Mocha is a feature-rich JavaScript test framework running on Node.js, and Chai is a BDD/TDD assertion library for Node.js that can be paired with any JavaScript testing framework.
// test/test.js
const chai = require('chai');
const expect = chai.expect;
describe('Array', function() {
describe('#indexOf()', function() {
it('should return -1 when the value is not present', function() {
expect([1, 2, 3].indexOf(4)).to.equal(-1);
});
});
});
Explanation
This example demonstrates how to write a simple test using Mocha and Chai. The test checks if the indexOf method of an array returns -1 when a value is not present in the array.
