action.yml

name: Retag action
description: Add a tag to a docker image
inputs:
  image:
    description: Image name
    required: true
    type: string
  tag:
    description: Current tag
    required: true
    type: string
  new-tag:
    description: New tag
    required: true
    type: string
  token:
    description: "GitHub token for logging into the ghcr container registry"
    required: false
    type: string
    default: ${{ github.token }}

runs:
  using: composite
  steps:
    - name: Login to GitHub Container Registry
      uses: docker/login-action@v3
      with:
        registry: ghcr.io
        username: ${{ github.actor }}
        password: ${{ inputs.token }}

    - name: Add a tag to an image
      shell: bash
      run: |
        docker pull ghcr.io/${{ inputs.image }}:${{ inputs.tag }}
        docker tag ghcr.io/${{ inputs.image }}:${{ inputs.tag }} ghcr.io/${{ github.repository }}:${{ inputs.new-tag }}
        docker push ghcr.io/${{ inputs.image }}:${{ inputs.new-tag }}