name: Docker

on:
  push:
    # Publish `main` as Docker `latest` image.
    branches:
      - main

    # Publish `v1.2.3` tags as releases.
    tags:
      - v*

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

env:
  IMAGE_NAME: conky
  DOCKERHUB_ACCOUNT: brndnmtthws
  DOCKER_BUILDKIT: 1

jobs:
  buildx:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v2
      - name: Set up QEMU
        uses: docker/setup-qemu-action@v2
      - name: Set up Docker Buildx
        id: buildx
        uses: docker/setup-buildx-action@v2
      - name: Log into Dockerhub registry
        run: echo "${{ secrets.DOCKERHUB_TOKEN }}" | docker login -u $DOCKERHUB_ACCOUNT --password-stdin
      - name: Build
        run: |
          DOCKERHUB_IMAGE_ID=$DOCKERHUB_ACCOUNT/$IMAGE_NAME

          # Change all uppercase to lowercase
          DOCKERHUB_IMAGE_ID=$(echo $DOCKERHUB_IMAGE_ID | tr '[A-Z]' '[a-z]')

          # Strip git ref prefix from version
          VERSION=$(echo "${{ github.ref }}" | sed -e 's,.*/\(.*\),\1,')

          # Strip "v" prefix from tag name
          [[ "${{ github.ref }}" == "refs/tags/"* ]] && VERSION=$(echo $VERSION | sed -e 's/^v//')

          # Use Docker `latest` tag convention
          [ "$VERSION" == "main" ] && VERSION=latest

          docker buildx build \
            --push \
            --platform linux/arm/v7,linux/arm64/v8,linux/amd64 \
            --cache-from=type=registry,ref=$DOCKERHUB_ACCOUNT/$IMAGE_NAME:buildcache \
            --cache-to=type=registry,ref=$DOCKERHUB_ACCOUNT/$IMAGE_NAME:buildcache,mode=max \
            --tag $DOCKERHUB_IMAGE_ID:$VERSION \
            .