docker-postfix/.github/workflows/container-image.yml

---
name: container image

on:
  push:
  pull_request:
  schedule:
  - cron: '0 20 * * 5'

jobs:
  docker-build:
    runs-on: ubuntu-24.04
    permissions: {packages: write}
    steps:
    - id: meta
      # > "automatic" tag management and OCI Image Format Spec… for labels
      # https://web.archive.org/web/20250103123053/https://docs.docker.com/build/ci/github-actions/manage-tags-labels/
      uses: docker/metadata-action@v5
      with:
        # see comment on `push: true` below
        images: ghcr.io/${{ github.repository_owner }}/postfix
        # https://web.archive.org/web/20250103130404/https://github.com/docker/metadata-action?tab=readme-ov-file#tags-input
        tags: |
          type=ref,event=branch
          type=ref,event=pr
          type=sha,format=long
          type=raw,value=latest,enable=false
    - uses: docker/setup-qemu-action@v3.6.0
    - uses: docker/login-action@v3
      with:
        registry: ghcr.io
        username: ${{ github.actor }}
        password: ${{ secrets.GITHUB_TOKEN }}
    - uses: docker/setup-buildx-action@v3.11.1
    # > By default, this action uses the Git context so you don't need to use
    # > the actions/checkout action to checkout the repository because this
    # > will be done directly by buildkit. [...]
    # > any file mutation in the steps that precede [...] will be ignored,
    # > including processing of the .dockerignore file
    # https://github.com/marketplace/actions/build-and-push-docker-images
    # > The commit history is not preserved.
    # https://docs.docker.com/engine/reference/commandline/build/#git-repositories
    - uses: docker/build-push-action@v6.18.0
      with:
        platforms: |
          linux/amd64
          linux/arm/v6
          linux/arm/v7
          linux/arm64
        # > Require approval for all external contributors
        # > All users that are not a member or owner of this repository will
        # > require approval to run workflows.
        # https://github.com/fphammerle/systemctl-mqtt/settings/actions
        push: true
        tags: ${{ steps.meta.outputs.tags }}
        labels: ${{ steps.meta.outputs.labels }}