Docker Build and Push to Registry

Docker Build & Push with GitHub Actions

Building and pushing Docker images is one of the most common CI/CD tasks. This workflow uses the official Docker actions to build an image, tag it, and push it to a container registry.

Workflow YAML

name: Docker Build & Push

on:
  push:
    branches:
      - main
    tags:
      - 'v*'

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ secrets.DOCKER_USERNAME }}
          password: ${{ secrets.DOCKER_PASSWORD }}

      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: myuser/myapp
          tags: |
            type=ref,event=branch
            type=semver,pattern={{version}}
            type=sha

      - name: Build and push
        uses: docker/build-push-action@v5
        with:
          context: .
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max

Key Components

• Docker Buildx: Enables advanced build features including multi-platform builds, build caching, and BuildKit optimizations.
• Login action: Authenticates with Docker Hub using repository secrets. For GitHub Container Registry (ghcr.io), use registry: ghcr.io with ${{ secrets.GITHUB_TOKEN }}.
• Metadata action: Automatically generates Docker tags based on Git refs — branch names, semantic version tags, and commit SHAs.
• GHA cache: The cache-from and cache-to options use GitHub Actions cache for Docker layer caching, dramatically speeding up rebuilds.

Multi-Platform Builds

Add platforms: linux/amd64,linux/arm64 to the build step for multi-architecture images. This is essential for supporting both x86 and ARM environments (Apple Silicon, AWS Graviton).

Tagging Strategy

The metadata action provides flexible tagging. The example tags produce: myuser/myapp:main for branch pushes, myuser/myapp:1.2.3 for version tags, and myuser/myapp:sha-abc1234 for commit-level tracking.