Git Workflows & GitHub Actions CI/CD

Git Workflows

GitHub Flow (Simple)

Best for teams deploying frequently:

main ──●──●──●──●──●──●──●──
        \       /
feature  ●──●──●

Create branch from main
Make commits
Open Pull Request
Review and discuss
Merge to main
Deploy

Git Flow (Complex)

Best for scheduled releases:

main    ──●─────────────────●── (releases)
           \               /
release     ●──●──●──●──●
             \       /
develop  ──●──●──●──●──●──●──
              \   /
feature        ●──●

Branches: main, develop, feature/*, release/*, hotfix/*

GitHub Actions

GitHub Actions automates workflows triggered by repository events.

Core Concepts

Concept	Description
Workflow	YAML file in `.github/workflows/`
Event	Trigger (push, PR, schedule)
Job	Set of steps running on a runner
Step	Individual task (action or command)
Runner	VM that executes jobs

Your First Workflow

Create .github/workflows/ci.yml:

name: CI Pipeline
 
on:
  push:
    branches: [main]
  pull_request:
    branches: [main]
 
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
 
      - name: Set up Python
        uses: actions/setup-python@v5
        with:
          python-version: "3.11"
 
      - name: Install dependencies
        run: pip install -r requirements.txt
 
      - name: Run tests
        run: pytest
 
      - name: Run linter
        run: flake8 .

Multi-Job Pipeline

name: Build and Deploy
 
on:
  push:
    branches: [main]
 
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: npm install
      - run: npm test
 
  build:
    needs: test  # Runs after test succeeds
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: npm run build
      - uses: actions/upload-artifact@v4
        with:
          name: build-output
          path: dist/
 
  deploy:
    needs: build
    runs-on: ubuntu-latest
    if: github.ref == 'refs/heads/main'
    steps:
      - uses: actions/download-artifact@v4
        with:
          name: build-output
      - run: echo "Deploying to production..."

Secrets and Variables

Store sensitive values in GitHub Settings → Secrets:

steps:
  - name: Deploy
    run: |
      echo "Deploying..."
      curl -X POST ${{ secrets.DEPLOY_URL }} \
        -H "Authorization: Bearer ${{ secrets.DEPLOY_TOKEN }}"
    env:
      NODE_ENV: production

Matrix Strategy

Test across multiple versions:

jobs:
  test:
    runs-on: ${{ matrix.os }}
    strategy:
      matrix:
        os: [ubuntu-latest, windows-latest]
        python-version: ["3.10", "3.11", "3.12"]
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-python@v5
        with:
          python-version: ${{ matrix.python-version }}
      - run: pytest

Docker in GitHub Actions

jobs:
  build-and-push:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
 
      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ secrets.DOCKER_USERNAME }}
          password: ${{ secrets.DOCKER_TOKEN }}
 
      - name: Build and push
        uses: docker/build-push-action@v5
        with:
          push: true
          tags: username/app:latest

Summary

GitHub Flow: simple branch → PR → merge → deploy
Git Flow: structured with develop, release, and hotfix branches
GitHub Actions workflows live in .github/workflows/*.yml
on: defines triggers; jobs: defines what runs
needs: creates job dependencies; if: adds conditions
Secrets store sensitive values securely
Matrix strategy tests across multiple configurations

Module Complete

You now understand Git version control and GitHub collaboration — from basic commits to automated CI/CD pipelines. These skills are foundational for every DevOps workflow.

Learning Objectives