Git and Continuous Integration/Continuous Deployment (CI/CD)

Integrating Git with CI/CD Tools

Popular CI/CD platforms and their Git integration:

GitHub Actions

# .github/workflows/build.yml
name: CI Pipeline
on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v3
    - run: npm install
    - run: npm test

Key features: Native GitHub integration, marketplace actions, matrix builds

GitLab CI/CD

# .gitlab-ci.yml
stages:
  - test
  - deploy

unit_tests:
  stage: test
  script:
    - npm install
    - npm test

deploy_prod:
  stage: deploy
  script:
    - npm run deploy
  only:
    - main

Key features: Built-in Docker support, auto DevOps, environments

Jenkins

// Jenkinsfile (Declarative Pipeline)
pipeline {
  agent any
  stages {
    stage('Build') {
      steps {
        git 'https://github.com/user/repo.git'
        sh 'make build'
      }
    }
    stage('Test') {
      steps {
        sh 'make test'
      }
    }
  }
}

Key features: Extensive plugins, distributed builds, pipeline as code

Automating Testing and Deployment

Effective CI/CD pipelines follow these principles:

Branching Strategies

Environment-based Workflow

main       → Automatic production deployment
release/* → Staging environment
feature/* → Development testing

Pipeline Stages

1. Linting: Code style validation
2. Unit Tests: Fast feedback on commits
3. Integration Tests: Service communication
4. Build Artifacts: Docker images/packages
5. Deployment: Environment-specific

Git Triggers

Trigger	Use Case
git push	Run tests on every commit
git tag	Trigger production deployment
Pull Request	Preview environments

GitOps: Infrastructure as Code

GitOps principles for infrastructure management:

Core Concepts

• Declarative: System state defined in Git
• Versioned: Complete change history
• Automated: CI/CD applies changes
• Observable: Drift detection

GitOps Workflow

1. Developer commits infrastructure changes
2. CI system validates changes
3. CD system applies to staging
4. Approval promotes to production
5. Monitoring detects any drift

Popular Tools

FluxCD

Kubernetes-native GitOps operator

ArgoCD

Declarative Kubernetes deployment

Terraform

Infrastructure as code with Git backends

GitOps Benefits

• Single source of truth for infrastructure
• Audit trail for compliance
• Rollback capability through Git history
• Collaboration via pull requests

CI/CD Best Practices with Git

• Keep pipeline execution under 10 minutes for PRs
• Use branch protection rules for critical branches
• Implement automated rollback procedures
• Store secrets in secure vaults, not in Git
• Monitor pipeline success/failure rates