buildah-build/.github/workflows/multiarch.yml

name: Multiarch build
on:
  push:
  pull_request:
  workflow_dispatch:
  schedule:
    - cron: '0 0 * * *'  # every day at midnight

env:
  IMAGE_NAME: hello-world-multiarch
  IMAGE_TAG: latest

jobs:
  build:
    name: Build image using Buildah
    runs-on: ubuntu-20.04
    strategy:
      fail-fast: false
      matrix:
        arch: [ amd64, i386, arm64v8 ]
    steps:

      # Checkout buildah action github repository
      - name: Checkout Buildah action
        uses: actions/checkout@v2
        with:
          path: "buildah-build"

      - name: Install qemu dependency
        run: sudo apt-get install -y qemu-user-static

      - name: Create Dockerfile
        run: |
          cat > Dockerfile<<EOF

          ARG ARCH
          FROM docker.io/\${ARCH}/alpine:3.14

          RUN echo "hello world"

          ENTRYPOINT [ "sh", "-c", "echo -n 'Machine: ' && uname -m && echo -n 'Bits: ' && getconf LONG_BIT && echo 'goodbye world'" ]
          EOF          

      - name: Build Image
        id: build_image
        uses: ./buildah-build/
        with:
          image: ${{ env.IMAGE_NAME }}
          tags: ${{ env.IMAGE_TAG }}
          arch: ${{ matrix.arch }}
          build-args: ARCH=${{ matrix.arch }}
          dockerfiles: |
            ./Dockerfile            

      - name: Echo Outputs
        run: |
          echo "Image: ${{ steps.build_image.outputs.image }}"
          echo "Tags: ${{ steps.build_image.outputs.tags }}"          

      - name: Check images created
        run: buildah images | grep '${{ env.IMAGE_NAME }}'

      - name: Check image metadata
        run: |
          set -x
          buildah inspect ${{ steps.build_image.outputs.image }}:${{ env.IMAGE_TAG }} | jq ".OCIv1.architecture"
          buildah inspect ${{ steps.build_image.outputs.image }}:${{ env.IMAGE_TAG }} | jq ".Docker.architecture"          

      - name: Run image
        run: |
          podman run --rm ${{ steps.build_image.outputs.image }}:${{ env.IMAGE_TAG }}