CI/CD Pipelines
CI/CD stands for Continuous Integration and Continuous Delivery/Deployment. It is a method to frequently deliver apps to customers by introducing automation into the stages of app development.
1. Continuous Integration (CI)
CI is the practice of automating the integration of code changes from multiple contributors into a single software project.
- Process: Developers frequently commit code to a shared repository (like GitHub). Each commit triggers an automated workflow that builds the code and runs tests.
- Goal: To find and fix bugs quicker, improve software quality, and reduce the time it takes to validate and release new software updates.
2. Continuous Delivery vs. Deployment
While often used interchangeably, there is a subtle difference:
- Continuous Delivery: The code changes are automatically built, tested, and prepared for a release to production. It requires a manual approval step to actually deploy to the live environment.
- Continuous Deployment: Every change that passes all stages of your production pipeline is released to your customers automatically. There is no human intervention.
3. The Pipeline Stages
A typical pipeline consists of several sequential stages:
- Source: A developer commits code to the version control system.
- Build: The application is compiled. Dependencies are installed. Docker images are built.
- Test: Automated tests (Unit, Integration) are run to ensure the new code didn't break anything.
- Deploy (Staging): The app is deployed to a staging environment that mimics production for final review.
- Deploy (Production): The app is deployed to the live servers.
4. Common Tools
- GitHub Actions: Integrated directly into GitHub. Uses YAML files.
- Jenkins: The classic open-source automation server. Highly customizable but complex.
- GitLab CI: Built into GitLab.
- CircleCI: A popular cloud-based CI/CD platform.
5. Example: GitHub Actions Workflow
Here is a simple example of a workflow defined in .github/workflows/main.yml that runs tests whenever code is pushed.
name: Node.js CI
on:
push:
branches: [ "main" ]
pull_request:
branches: [ "main" ]
jobs:
build:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v3
- name: Use Node.js
uses: actions/setup-node@v3
with:
node-version: '18.x'
- run: npm ci
- run: npm run build --if-present
- run: npm testprogramming/docker-and-containers programming/microservices-architecture programming/debugging-techniques