name: Build container image
on:
  workflow_dispatch:
  push:
    branches:
      - 'main'
    tags:
      - '*'
  pull_request:
    paths:
      - .github/workflows/build-image.yml
      - Dockerfile
jobs:
  build-image:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        os: [linux/arm64, linux/amd64]
    steps:
      - uses: actions/checkout@v2
      - uses: docker/setup-qemu-action@v1
      - uses: docker/setup-buildx-action@v1
      - uses: docker/login-action@v1
        with:
          registry: ghcr.io
          username: ${{ github.repository_owner }}
          password: ${{ secrets.GITHUB_TOKEN }}
        if: github.event_name != 'pull_request'
      - uses: docker/metadata-action@v3
        id: meta
        with:
          images: ghcr.io/${{ github.repository_owner }}/mastodon
          flavor: |
            latest=true
          tags: |
            type=edge,branch=main
            type=match,pattern=v(.*),group=0
            type=ref,event=pr
      - uses: docker/build-push-action@v2
        with:
          context: .
          platforms: ${{ matrix.os }}
          push: ${{ github.event_name != 'pull_request' }}
          tags: ${{ steps.meta.outputs.tags }}
          cache-from: type=registry,ref=ghcr.io/${{ github.repository_owner }}/mastodon:latest
          cache-to: type=inline