container.yml

# This workflow builds and publishes a docker container to the GitHub registry.
# It is only triggered on merges into the main branch, and we assume that
# any commit merged into the trunk has passed CI is safe to release.

# Adapted from https://docs.github.com/en/actions/publishing-packages/publishing-docker-images#publishing-images-to-github-packages

name: docker-container

on:
  release:
    types:
      - published
  push:
    branches:
      - main

env:
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}

jobs:
  build-and-push-image:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write

    steps:
      - name: Checkout repository
        uses: actions/checkout@v2

      - name: Log in to the Container registry
        uses: docker/login-action@f054a8b539a109f9f41c372932f1ae047eff08c9
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      # See https://github.com/docker/metadata-action#tags-input for the default
      # tags that are extracted this way. It includes tags for semver releases
      # and any branches into main
      - name: Extract metadata (tags, labels) for Docker
        id: meta
        uses: docker/metadata-action@98669ae865ea3cffbcbaa878cf57c20bbf1c6c38
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}

      # Our Dockerfile is specified in the build.sbt file, so we need to
      # generate the file along with the artifacts it requires for inclusion
      # in the image.
      - name: Build Dockerfile
        run: make docker

      - name: Build and push Docker image
        uses: docker/build-push-action@ad44023a93711e3deb337508980b4b5e9bcdc5dc
        with:
          context: target/docker
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}