docker-publish.yml

name: Docker

on:
  push:

env:
  IMAGE_NAME: emdocker-test

jobs:
  # Push image to GitHub Packages.
  # See also https://docs.docker.com/docker-hub/builds/
  push:
    runs-on: ubuntu-latest
    container:
      image: ghcr.io/owner/image
      credentials:
        username: ${{ github.actor }}
        password: ${{ secrets.github_token }}
    steps:
      - uses: actions/checkout@v2

      - name: Build image
        run: echo "${{ secrets.GITHUB_TOKEN }}" | docker login docker.pkg.github.com -u ${{ github.actor }} --password-stdin && docker build . --file Dockerfile --tag $IMAGE_NAME

      - name: Log into registry
        run: echo "${{ secrets.GITHUB_TOKEN }}" | docker login docker.pkg.github.com -u ${{ github.actor }} --password-stdin

      - name: Push image
        run: |
          IMAGE_ID=docker.pkg.github.com/${{ github.repository }}/$IMAGE_NAME
          
          # Change all uppercase to lowercase
          IMAGE_ID=$(echo $IMAGE_ID | tr '[A-Z]' '[a-z]')

          # Strip git ref prefix from version
          VERSION=$(echo "${{ github.ref }}" | sed -e 's,.*/\(.*\),\1,')

          # Strip "v" prefix from tag name
          [[ "${{ github.ref }}" == "refs/tags/"* ]] && VERSION=$(echo $VERSION | sed -e 's/^v//')

          # Use Docker `latest` tag convention
          [ "$VERSION" == "master" ] && VERSION=latest

          echo IMAGE_ID=$IMAGE_ID
          echo VERSION=$VERSION

          docker tag $IMAGE_NAME $IMAGE_ID:$VERSION
          docker push $IMAGE_ID:$VERSION