Creating a CI/CD Pipeline for a Node.js Express Project on GitLab with AWS Integration

In today’s fast-paced development environment, continuous integration and continuous deployment (CI/CD) have become essential to streamline the development process and reduce downtime. GitLab CI/CD provides an effective way to automate testing, building, and deploying applications. In this article, we'll walk through how to set up a CI/CD pipeline for a Node.js Express project hosted on GitLab and deploy it to AWS.

Prerequisites

• Before getting started, ensure you have the following:
• A Node.js and Express-based project on GitLab.
• An AWS account with access to EC2, S3, or Elastic Beanstalk (depending on your deployment).
• AWS CLI configured with proper credentials on your local machine.
• Docker installed (optional, but recommended for containerized deployments).
• Basic understanding of GitLab CI/CD and AWS services.

Step 1: Setup GitLab CI/CD Pipeline Configuration

GitLab pipelines are defined using the .gitlab-ci.yml file located in the root of your repository. This file contains instructions for how the CI/CD process should work for your project. Let’s begin by creating this file for our Node.js Express project.

# .gitlab-ci.yml

stages:
  - install
  - test
  - build
  - deploy

cache:
  paths:
    - node_modules/

install_dependencies:
  stage: install
  image: node:18
  script:
    - npm install
  only:
    - main

test:
  stage: test
  image: node:18
  script:
    - npm test
  only:
    - merge_requests

build:
  stage: build
  image: node:18
  script:
    - npm run build
  only:
    - main

deploy_to_aws:
  stage: deploy
  image: node:18
  environment: production
  script:
    - apt-get update -y
    - apt-get install -y awscli
    - aws s3 cp ./build s3://your-s3-bucket-name --recursive
  only:
    - main        

Step 2: Pipeline Breakdown

• Stages: In the configuration, we have four stages: install, test, build, and deploy. These stages run in sequence, ensuring that our application is installed, tested, built, and deployed correctly.
• Cache: We cache the node_modules directory to speed up consecutive builds. GitLab stores the cache between pipelines.
• Install Dependencies (Stage 1): The install_dependencies job installs project dependencies using npm install from a Node.js Docker image.
• Testing (Stage 2): In this stage, we run the tests to ensure everything works properly before deploying. Tests are triggered only on merge requests to avoid running them unnecessarily on every commit.
• Build (Stage 3): This stage runs the build script (`npm run build`). It’s triggered on the main branch, ensuring only committed changes on the main branch will be built and deployed.
• Deployment (Stage 4): The final step deploys the build to AWS. The example above uses the AWS CLI to upload the build files to an S3 bucket. You can modify this step to deploy to EC2 or Elastic Beanstalk if needed.

Step 3: Configure AWS for Deployment

Make sure your AWS credentials are securely stored. GitLab offers a way to store your secrets via CI/CD variables.

1. Go to your GitLab project.

2. Navigate to Settings -> CI/CD -> Variables.

3. Add the following variables:

- AWS_ACCESS_KEY_ID (Your AWS access key)

- AWS_SECRET_ACCESS_KEY (Your AWS secret key)

- AWS_REGION (The region of your S3 bucket or deployment environment)

These variables will be injected into the pipeline’s environment during runtime.

Step 4: Trigger the Pipeline

After committing your .gitlab-ci.yml file, the pipeline will automatically trigger on the main branch. You can monitor its progress by going to your GitLab project’s CI/CD -> Pipelines section.

- For pull requests (merge requests): The test stage will run to ensure everything passes before merging into the main branch.

- For main branch: The pipeline will execute all stages (install, test, build, and deploy).

Step 5: Deploy to AWS

In the example, we deploy to an S3 bucket. This can easily be adjusted for other AWS services like EC2, ECS, or Elastic Beanstalk.

For EC2:

- SSH into the EC2 instance and pull the code from GitLab or download the build artifacts using the AWS CLI.

For Elastic Beanstalk:

- Use the AWS Elastic Beanstalk CLI to deploy the application by modifying the deploy_to_aws script in the .gitlab-ci.yml file.

script:
  - eb init -p node.js express-app --region $AWS_REGION
  - eb deploy        

Conclusion

With GitLab CI/CD and AWS, you can automate the entire development workflow for your Node.js Express project. From running tests to deploying your app on AWS, this setup ensures consistency, reliability, and quicker iterations.

By automating your pipeline, you’ll save time, reduce human errors, and make your deployments more efficient. Whether it’s a simple S3 deployment or a more complex setup with EC2 or Elastic Beanstalk, GitLab CI/CD and AWS provide the tools you need to streamline your process.