Example docker github action

docker-publish.yml

# Adapted from https://github.com/users/jeliasson/packages/container/package/redwoodjs-app-api-main
name: 'Github Publish Docker'
on:
  workflow_dispatch:
    inputs:
      image_tag_prefix:
        description: 'Image Tag Prefix (dev or sandbox)'
        required: true
        default: 'dev'
env:
  REDWOOD_API_URL: 'http://0.0.0.0:8911'
  APP_DOMAIN: 'http://0.0.0.0:8910'
  BASIC_AUTH_PASSWORD: 'pauliemorphy'

  # Container Registry
  CONTAINER_REGISTRY_HOSTNAME: ghcr.io
  CONTAINER_REGISTRY_USERNAME: ${{ github.actor }}
  CONTAINER_REGISTRY_PASSWORD: ${{ secrets.GITHUB_TOKEN }}

jobs:
  setup:
    name: Setup
    runs-on: ubuntu-20.04
    continue-on-error: true
    outputs:
      RELEASE_HTML_URL: ${{ steps.get_release.outputs.html_url }}
      BRANCH: ${{ steps.get_variables.outputs.VERSION }}
      ENVIRONMENT: ${{ steps.get_variables.outputs.ENVIRONMENT }}
      VERSION: ${{ steps.get_version.outputs.VERSION }}
    steps:
      - name: Show context
        run: |
          echo github.event_name: ${{ github.event_name }}
          echo github.sha: ${{ github.sha }}
          echo github.repository: ${{ github.repository }}
          echo github.ref: ${{ github.ref }}
          echo github.head_ref: ${{ github.head_ref }}
          echo github.event.inputs.image_tag_prefix: ${{ github.event.inputs.image_tag_prefix }}
      - name: Get release
        id: get_release
        continue-on-error: true
        uses: bruceadams/get-release@v1.2.3
        env:
          GITHUB_TOKEN: ${{ github.token }}
      - name: Get variables
        id: get_variables
        run: |
          ENVIRONMENT=staging
          BRANCH=${{ steps.get_release.outputs.tag_name }}
          if [ ${{ github.event.inputs.image_tag_prefix }} ] ; then
             ENVIRONMENT=${{ github.event.inputs.image_tag_prefix }}
             BRANCH=${{ github.ref_name }}
          elif ! grep -q "staging" <<< "${{ steps.get_release.outputs.tag_name }}" ; then
             ENVIRONMENT=prod
          fi
          echo BRANCH: $BRANCH
          echo ENVIRONMENT: $ENVIRONMENT
          echo "::set-output name=BRANCH::$BRANCH"
          echo "::set-output name=ENVIRONMENT::$ENVIRONMENT"
      - name: Checkout branch
        uses: actions/checkout@v2
        with:
          token: ${{ secrets.PAT_GITHUB }}
          ref: ${{ steps.get_variables.outputs.BRANCH }}
      - name: Get version
        id: get_version
        env:
          GH_TOKEN: ${{ secrets.PAT_GITHUB }}
        run: |
          VERSION=${{ steps.get_variables.outputs.BRANCH }}
          if [ ${{ github.event.inputs.image_tag_prefix }} ] ;  then
            VERSION=${{ steps.get_variables.outputs.BRANCH }}-$(echo $GITHUB_SHA | cut -c 1-7)
          fi
          echo "::set-output name=VERSION::$VERSION"
      - name: Discord notify building
        env:
          DISCORD_WEBHOOK: ${{ secrets.DISCORD_WEBHOOK_RELEASE }}
        uses: Ilshidur/action-discord@0c4b27844ba47cb1c7bee539c8eead5284ce9fa9
        with:
          args: 🏭 Building... `${{ steps.get_version.outputs.VERSION }}` for GHCR
  build:
    name: Build
    runs-on: ubuntu-20.04
    needs: setup
    timeout-minutes: 35
    strategy:
      fail-fast: true
      matrix:
        platform: [api, web]
    steps:
      - name: Checkout branch
        uses: actions/checkout@v2
        with:
          ref: ${{ needs.setup.outputs.BRANCH }}
      - name: Setup Docker
        uses: docker/setup-buildx-action@v1
      - name: Docker login
        uses: docker/login-action@v1
        with:
          registry: ${{ env.CONTAINER_REGISTRY_HOSTNAME }}
          username: ${{ env.CONTAINER_REGISTRY_USERNAME }}
          password: ${{ env.CONTAINER_REGISTRY_PASSWORD }}
      - name: Docker build
        uses: docker/build-push-action@v2
        with:
          push: true
          context: .
          file: ./${{ matrix.platform }}/Dockerfile
          build-args: |
            ENVIRONMENT=${{ needs.setup.outputs.ENVIRONMENT }}
            REDWOOD_API_URL=${{ env.REDWOOD_API_URL }}
            APP_DOMAIN=${{ env.APP_DOMAIN }}
            VERSION=${{ needs.setup.outputs.VERSION }}
            SENTRY_DSN=${{ env.SENTRY_DSN }}
            SENTRY_ENVIRONMENT=${{ env.SENTRY_ENVIRONMENT }}
          tags: |
            ${{ env.CONTAINER_REGISTRY_HOSTNAME }}/${{ github.repository }}-${{ matrix.platform }}:latest
            ${{ env.CONTAINER_REGISTRY_HOSTNAME }}/${{ github.repository }}-${{ matrix.platform }}:${{ needs.setup.outputs.VERSION }}
  notify:
    name: Notify
    runs-on: ubuntu-20.04
    needs:
      - build
      - setup
    steps:
      - name: Discord notify complete
        env:
          DISCORD_WEBHOOK: ${{ secrets.DISCORD_WEBHOOK_RELEASE }}
        uses: Ilshidur/action-discord@0c4b27844ba47cb1c7bee539c8eead5284ce9fa9
        with:
          args: |
            🚢 Shipped! `${{ needs.setup.outputs.VERSION }}` ${{ needs.setup.outputs.RELEASE_HTML_URL }}