Day 85: GitLab CI/CD Project

Today I built a full GitLab CI/CD pipeline for a simple Node.js app using Docker and deploying it to AWS. This was one of the most practical exercises yet, as it tied together GitLab runners, Docker, Docker Hub, and AWS deployment.

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🔹 Pipeline Overview

My pipeline had 4 stages:

1️⃣ Build → Build the Docker image for the Node.js app
2️⃣ Test → Run basic checks/tests
3️⃣ Push to Docker Hub → Push the built image to Docker Hub
4️⃣ Deploy to AWS → Deploy using Docker Compose on an AWS EC2

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🔹 .gitlab-ci.yml Pipeline Code

stages:
  - build
  - test
  - push_to_docker
  - deploy_to_aws

variables:
  DOCKERIMAGE_NAME: node-app

build_stage:
  script:
    - docker build -t $DOCKERIMAGE_NAME:$CI_COMMIT_REF_SLUG ./gitlab-ci/01__node-todo-cicd
  tags:
    - deploy

test_job:
  stage: test
  script:
    - echo "testing the image ..."

push_job:
  stage: push_to_docker
  script:
    - docker login -u $DOCKERHUB_USER -p $DOCKERHUB_PASS
    - docker image tag $DOCKERIMAGE_NAME:$CI_COMMIT_REF_SLUG $DOCKERHUB_USER/$DOCKERIMAGE_NAME:$CI_COMMIT_REF_SLUG
    - docker push $DOCKERHUB_USER/$DOCKERIMAGE_NAME:$CI_COMMIT_REF_SLUG
  tags:
    - deploy

deploy_job:
  stage: deploy_to_aws
  script:
    - echo "deploying to AWS..."
    - docker compose -f ./gitlab-ci/01__node-todo-cicd/docker-compose.yaml up -d
  tags:
    - deploy

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🔹 Key Learnings

✅ How to use GitLab variables like $CI_COMMIT_REF_SLUG for versioning
✅ How to authenticate & push images to Docker Hub securely
✅ Using GitLab self-hosted runner with Docker to run builds/deployments
✅ Simple AWS deployment with Docker Compose

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🔹 Why This Matters

This exercise showed me how powerful GitLab CI/CD can be when integrated with Docker and AWS. Instead of manually building/pushing/deploying, the entire process becomes automated, repeatable, and reliable.

I now have a mini production pipeline:
Code → Build → Test → Push → Deploy 🚀