name: Build

on:
  workflow_run:
    workflows: ["Lint & Test"]
    branches:
      - main
    types:
      - completed

jobs:
  build:
    name: Build Docker Image
    if: github.event.workflow_run.conclusion == 'success' && github.event.workflow_run.event == 'push'
    runs-on: ubuntu-latest

    steps:
      # Create a commit SHA-based tag for the container repositories
      - name: Create SHA Container Tag
        id: sha_tag
        run: |
          tag=$(cut -c 1-7 <<< $GITHUB_SHA)
          echo "::set-output name=tag::$tag"

      - name: Checkout code
        uses: actions/checkout@v2

      # The current version (v2) of Docker's build-push action uses
      # buildx, which comes with BuildKit features that help us speed
      # up our builds using additional cache features. Buildx also
      # has a lot of other features that are not as relevant to us.
      #
      # See https://github.com/docker/build-push-action
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v1

      - name: Login to Github Container Registry
        uses: docker/login-action@v1
        with:
          registry: ghcr.io
          username: ${{ github.repository_owner }}
          password: ${{ secrets.GITHUB_TOKEN }}

      # Build the container, including an inline cache manifest to
      # allow us to use the registry as a cache source.
      - name: Build and push
        uses: docker/build-push-action@v2
        with:
          context: .
          file: ./Dockerfile
          push: true
          cache-from: type=registry,ref=ghcr.io/python-discord/site:latest
          cache-to: type=inline
          tags: |
            ghcr.io/python-discord/site:latest
            ghcr.io/python-discord/site:${{ steps.sha_tag.outputs.tag }}
          build-args: |
            git_sha=${{ github.sha }}