action.yml

name: 'Docker Skiko Publish'
description: 'Build and optionally publish a Docker image to ghcr.io for skiko'

inputs:
  image_name:
    description: 'Image name (e.g., linux-compat)'
    required: true
  platforms:
    description: 'Target platforms (e.g., linux/amd64 or linux/amd64,linux/arm64). If not specified, uses runner architecture.'
    required: false
  tag:
    description: 'Image tag (e.g., latest)'
    required: true
  load:
    description: 'Whether to load the image into the local Docker daemon'
    required: false
    default: 'false'
  should_publish:
    description: 'Whether to push the image to the registry'
    required: true
  github_token:
    description: 'GitHub token for authentication (required only if should_publish is true)'
    required: false

runs:
  using: 'composite'
  steps:
    - name: 'Set Variables'
      id: vars
      shell: bash
      run: |
        echo "image_namespace=${GITHUB_REPOSITORY,,}" >> $GITHUB_OUTPUT
        
        # Normalize tag: replace invalid docker tag characters
        TAG="${{ inputs.tag }}"
        TAG="${TAG//\//-}"
        echo "tag=${TAG}" >> $GITHUB_OUTPUT

    - name: 'Set up Docker Buildx'
      uses: docker/setup-buildx-action@v3

    - name: 'Log into registry'
      if: inputs.should_publish == 'true'
      uses: docker/login-action@v3
      with:
        registry: ghcr.io
        username: ${{ github.actor }}
        password: ${{ inputs.github_token }}

    - name: 'Extract metadata'
      id: meta
      uses: docker/metadata-action@v5
      with:
        images: ghcr.io/${{ steps.vars.outputs.image_namespace }}/${{ inputs.image_name }}
        tags: |
          type=raw,value=${{ steps.vars.outputs.tag }}

    - name: 'Build and push'
      uses: docker/build-push-action@v5
      with:
        context: ./skiko/docker/${{ inputs.image_name }}
        platforms: ${{ inputs.platforms }}
        push: ${{ inputs.should_publish == 'true' }}
        load: ${{ inputs.load == 'true' }}
        tags: ${{ steps.meta.outputs.tags }}
        labels: ${{ steps.meta.outputs.labels }}
        cache-from: type=gha
        cache-to: type=gha,mode=max