name: Docker Image CI

on:
  push:
    branches: [ main ]
    tags:
      - v*

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2

    - name: Prepare
      id: prepare
      run: |
        DOCKER_IMAGE=averagemarcus/tailscale-exporter
        DOCKER_PLATFORMS=linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64,linux/386,linux/ppc64le,linux/s390x

        VERSION=latest
        if [[ $GITHUB_REF == refs/tags/* ]]; then
          VERSION=${GITHUB_REF#refs/tags/}
        fi

        TAGS="--tag ${DOCKER_IMAGE}:${VERSION}"
        if [[ $VERSION =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
          TAGS="$TAGS --tag ${DOCKER_IMAGE}:latest"
        fi

        echo ::set-output name=tags::${TAGS}
        echo ::set-output name=platforms::${DOCKER_PLATFORMS}

    - name: Set up Docker Buildx
      uses: crazy-max/ghaction-docker-buildx@v3

    - name: Cache Docker layers
      uses: actions/cache@v2
      id: cache
      with:
        path: /tmp/.buildx-cache
        key: ${{ runner.os }}-buildx-${{ github.sha }}
        restore-keys: |
          ${{ runner.os }}-buildx-

    - name: Docker Buildx (build)
      run: |
        docker buildx build \
          --cache-from "type=local,src=/tmp/.buildx-cache" \
          --cache-to "type=local,dest=/tmp/.buildx-cache" \
          --platform ${{ steps.prepare.outputs.platforms }} \
          --output "type=image,push=false" \
          ${{ steps.prepare.outputs.tags }} \
          .

    - name: Docker Login
      env:
        DOCKER_USERNAME: averagemarcus
        DOCKER_PASSWORD: ${{ secrets.DOCKER_TOKEN }}
      run: |
        echo "${DOCKER_PASSWORD}" | docker login --username "${DOCKER_USERNAME}" --password-stdin

    - name: Docker Buildx (push)
      run: |
        docker buildx build \
          --cache-from "type=local,src=/tmp/.buildx-cache" \
          --cache-to "type=local,dest=/tmp/.buildx-cache" \
          --platform ${{ steps.prepare.outputs.platforms }} \
          --output "type=image,push=true" \
          ${{ steps.prepare.outputs.tags }} \
          .