action.yml

name: 'Github Docker tag delete'
description: 'Action allows you to remove Docker tag from the package repository in Github'
inputs:
  tag_name:
    description: 'Name of Docker tag to delete'
    required: true
  github_token:
    description: 'GITHUB_TOKEN is required to login to Container registry and use Github API'
    required: true
  is_organization:
    description: 'Organization accounts have different API endpoints. Set this to true to use it within org'
    required: false
    type: boolean
    default: false
    
# The Action can be used from a private repository. If so, the following input must be used.
  private_repo_token:
    description: 'GITHUB_TOKEN with access to private repository'
    default: ''

runs:
  using: "composite"  
  steps: 
    - name: Checkout if private repository
      if: ${{ inputs.private_repo_token != '' }}
      uses: actions/checkout@v4
      with:
        repository: ${{ env.GH_ACTION_REPOSITORY }}
        token: ${{ inputs.private_repo_token }}
      env:
        GH_ACTION_REPOSITORY: ${{ github.action_repository }}   

    - name: Checkout repository
      if: ${{ inputs.private_repo_token == '' }}
      uses: actions/checkout@v4
      with:
        repository: ${{ env.GH_ACTION_REPOSITORY }}
      env:
        GH_ACTION_REPOSITORY: ${{ github.action_repository }}   

    - name: Log in to the Container registry
      uses: docker/login-action@v3.0.0
      with:
          registry: ghcr.io
          username: ${{ github.repository_owner }}
          password: ${{ inputs.github_token }}

# CURRENT_TIME is needed to create dummy Docker image. REPO_NAME is made using bash parameter expansion. GITHUB_ENV store vars within job.
    - name: Set ENV variables
      shell: bash
      run: | 
        echo "CURRENT_TIME=$(date +%Y-%m-%d_%H-%M-%S)" >> $GITHUB_ENV
        echo "REPO_NAME=${GITHUB_REPOSITORY#$GITHUB_REPOSITORY_OWNER/}" >> $GITHUB_ENV

# Check if is_organization is true, if so change GH_API_PREFIX env accordingly.
    - name: Check if user or organization
      shell: bash
      run: |
        if [ ${{ inputs.is_organization }} == "true" ]; then
          echo "The boolean input is set to true => orgs api endpoint"
          echo "GH_API_PREFIX=orgs" >> $GITHUB_ENV
        else
          echo "The boolean input is set to false => users api endpoint"
          echo "GH_API_PREFIX=users" >> $GITHUB_ENV
        fi

  # Lowercase repository name using Bash Shell Parameter Expansion
    - name: Lowercase repository
      shell: bash
      run: |
        echo "GITHUB_REPOSITORY_LOWERCASE=${GITHUB_REPOSITORY@L}" >> $GITHUB_ENV

# Dummy Docker image is created and pushed to Github package repository.
    - name: Build and push Docker image
      id: build-push-action
      uses: docker/build-push-action@v5
      with:
        context: .
        build-args: |
          TIME_STAMP=$CURRENT_TIME
        push: true
        tags: ghcr.io/${{ env.GITHUB_REPOSITORY_LOWERCASE }}:${{ inputs.tag_name }}

# Look for the package that was created in the previous step using its digest.
    - name: Get package id
      shell: bash
      run: |
          GH_package_id=$(gh api \
          -H "Accept: application/vnd.github+json" \
          -H "X-GitHub-Api-Version: 2022-11-28" \
          /${{env.GH_API_PREFIX}}/${{github.repository_owner}}/packages/container/${{env.REPO_NAME}}/versions | \
          jq -r '.[] | select(.name == "${{ steps.build-push-action.outputs.digest }}") | .id')
          echo "GH_package_id=$GH_package_id" >> $GITHUB_ENV
      env:
        GITHUB_TOKEN: ${{ inputs.github_token }}

# Delete the package using the ID found in the previous step.
    - name: Delete package by id
      shell: bash
      run: |
        gh api \
        --method DELETE \
        -H "Accept: application/vnd.github+json" \
        -H "X-GitHub-Api-Version: 2022-11-28" \
        /${{env.GH_API_PREFIX}}/${{github.repository_owner}}/packages/container/${{env.REPO_NAME}}/versions/${{env.GH_package_id}}
      env:
        GITHUB_TOKEN: ${{ inputs.github_token }}