build_and_publish.yml

name: Build & Publish
on:
  push:
    branches:
      - "master"
jobs:
  test:
    runs-on: ubuntu-20.04
    strategy:
      matrix:
        version:
          - {
              distro: alpine,
              rel: 3.14,
              dnsmasq: 2.85-r2,
              tag: "4km3/dnsmasq:2.85-r2",
            }
          - {
              distro: alpine,
              rel: 3.15,
              dnsmasq: 2.86-r0,
              tag: "4km3/dnsmasq:2.86-r0",
              taglatest: "4km3/dnsmasq:latest",
            }
          - { distro: alpine, rel: edge, dnsmasq: 2.86-r0 }
    steps:
      - uses: actions/checkout@v3
      - name: Check credentials
        id: docker-credentials
        run: |
          echo ::set-output name=defined::$(test -n "${{ secrets.DOCKERHUB_USERNAME }}" && echo true || echo false)
      - name: Set up QEMU
        uses: docker/setup-qemu-action@v1
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v1
      - name: Login to DockerHub
        if: steps.docker-credentials.outputs.defined == 'true'
        uses: docker/login-action@v1
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_PASSWORD }}
      - name: Build and push
        if: steps.docker-credentials.outputs.defined == 'true'
        id: docker_build
        uses: docker/build-push-action@v2
        with:
          context: .
          build-args: ALPINE_VERSION=${{ matrix.version.rel }}
          platforms: linux/amd64,linux/arm64,linux/arm/v7
          push: true
          tags: |
            "4km3/dnsmasq:${{ matrix.version.dnsmasq }}-${{ matrix.version.distro }}-${{ matrix.version.rel }}"
            ${{ matrix.version.tag }}
            ${{ matrix.version.taglatest }}
      - name: Image digest
        run: echo ${{ steps.docker_build.outputs.digest }}