publish-on-release.yaml

# loosley based on https://docs.github.com/en/actions/publishing-packages/publishing-docker-images#publishing-images-to-github-packages
#
# a push to "/refs/heads/releases/v1" results in a tag of "releases-v1" per https://github.com/docker/metadata-action#usage

name: Create and publish a Docker image on release

on:
  push:
    branches: ['release']
  workflow_dispatch:

env:
  REGISTRY: us-docker.pkg.dev/uwit-mci-iam/containers
  OWNER_IMAGE: ${{ github.repository }}

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

    steps:
      - name: Checkout repo
        uses: actions/checkout@v4

      - name: Compute repository name
        id: image_name
        run: |
          # GH=uwit-iam/nginx-saml-proxy; echo ${GH#*/} returns "nginx-saml-proxy"
          echo "IMAGE_NAME=${OWNER_IMAGE#*/}" >> $GITHUB_OUTPUT

      - name: Auth to Cloud
        uses: 'uwit-iam/action-auth-artifact-registry@main'
        with:
          credentials: "${{ secrets.MCI_GCLOUD_AUTH_JSON }}"

      - name: Extract metadata (tags + labels) for Docker
        id: meta
        # should this be pinned?
        # https://github.com/docker/metadata-action
        uses: docker/metadata-action@v5.5.1
        with:
          images: ${{ env.REGISTRY }}/${{ steps.image_name.outputs.IMAGE_NAME }}

      - name: Build and push Docker image
        # should this be pinned?
        # https://github.com/docker/build-push-action
        uses: docker/build-push-action@v6.7.0
        with:
          context: .
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.output.labels }}