docker.yml

---
name: Docker

on:
  workflow_dispatch:
  pull_request:
    paths-ignore:
      - "docs/**"
  push:
    paths-ignore:
      - "docs/**"
    branches:
      - master
      - "v*.*.*"

jobs:
  build:
    strategy:
      matrix:
        os: [alpine, debian]
    runs-on: ubuntu-22.04
    steps:
      - uses: actions/checkout@v3

      - name: Set up QEMU
        uses: docker/setup-qemu-action@master
        with:
          platforms: amd64

      - name: Set up Docker Build
        uses: docker/setup-buildx-action@v2.4.1

      # ARM build takes very long time, so we build PRs for AMD64 only
      - name: Select target platform
        id: select_platforms
        run: |
          if  [[ "${GITHUB_EVENT_NAME}" == "pull_request" ]] ; then
            echo "build_platforms=linux/amd64" >> $GITHUB_ENV
          else
            echo "build_platforms=linux/amd64,linux/arm64" >> $GITHUB_ENV
          fi

      - name: Build Docker sample image
        id: docker_build
        uses: docker/build-push-action@v4.0.0
        with:
          context: .
          file: ./Dockerfile-${{ matrix.os }}
          build-args: |
            REVISION=${{ github.ref }}
          platforms: ${{ env.build_platforms }}
          push: false
          cache-from: |
            type=gha
          cache-to: |
            type=gha,mode=max

      - name: Show Docker image digest
        run: echo ${{ steps.docker_build.outputs.digest }}