p_mail/.github/workflows/docker_build_pre.yml

name: Docker Image CI Pre

on:
  workflow_dispatch:
  release:
    types: [ prereleased ]

env:
  REGISTRY: ghcr.io

jobs:
  build-and-push-image:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
    steps:
      - name: Get version
        id: get_version
        run: |
          echo "VERSION=pre${GITHUB_REF/refs\/tags\//}" >> ${GITHUB_ENV}
          echo "${GITHUB_REF/refs\/tags\//}"
          echo "${GITHUB_REF#refs/*/}"
          echo "${GITHUB_REF}"
      - uses: actions/checkout@v3

      - name: set lower case repository name
        run: |
          echo "REPOSITORY_LC=${REPOSITORY,,}" >> ${GITHUB_ENV}
        env:
          REPOSITORY: '${{ github.repository }}'

      - name: Log in to the Container registry
        uses: docker/login-action@v2.1.0
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Build and push Docker images
        uses: docker/build-push-action@v4
        with:
          context: .
          push: true
          tags: |
            ${{ env.REGISTRY }}/${{ env.REPOSITORY_LC }}:${{ env.VERSION }}