build-publish.yml

name: build & publish Docker image

on:
  push:
    branches:
      - main

jobs:
  lint:
    name: lint
    uses: './.github/workflows/lint.yml'

  build-publish:
    needs: [lint]
    runs-on: ubuntu-latest
    steps:
    - name: checkout
      uses: actions/checkout@v4

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

    - name: log into the GitHub Container Registry
      uses: docker/login-action@v3
      with:
        registry: ghcr.io
        username: ${{ github.actor }}
        password: ${{ github.token }}

    - name: set date-based tag
      run: |
        echo "DATE_TIME_TAG=$(date '+%Y-%m-%dT%H-%M')" >> $GITHUB_ENV

    - name: build and push Docker image
      uses: docker/build-push-action@v6
      with:
        push: true
        tags: |
          ghcr.io/${{ github.repository }}:latest
          ghcr.io/${{ github.repository }}:${{ env.DATE_TIME_TAG }}
        platforms: linux/amd64,linux/arm64
        # https://docs.docker.com/build/ci/github-actions/cache/#cache-backend-api
        cache-from: type=gha
        cache-to: type=gha,mode=max