Building Docker in CI

GitHub Actions runners (like ubuntu-latest) come with Docker pre-installed!

This means you can run standard Docker commands directly in your run steps.

jobs:
  build-image:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      
      - name: Build the Docker image
        run: docker build -t myapp:latest .

Alternatively, Docker provides official Actions (docker/build-push-action@v5) which offer advanced features like caching layers using GitHub Actions cache to drastically speed up build times.