action.yml

name: 'Docker Golden Image: Build PR Image'
description: 'Builds and pushes a Docker image for a Pull Request and comments on the PR with tags.'

inputs:
  dockerfile_path:
    description: 'Path to Dockerfile'
    required: false
    default: './Dockerfile'
  docker_context:
    description: 'Docker build context path'
    required: false
    default: '.'
  registry:
    description: 'Container registry URL'
    required: false
    default: 'ghcr.io'
  image_name:
    description: 'Image name (defaults to repository name)'
    required: false
    default: ''
  build_args:
    description: 'Docker build arguments (comma-separated KEY=VALUE pairs)'
    required: false
    default: ''
  platforms:
    description: 'Target platforms for build'
    required: false
    default: 'linux/amd64'
  registry_username:
    description: 'Registry username'
    required: false
  registry_password:
    description: 'Registry password'
    required: true

runs:
  using: 'composite'
  steps:
    - name: Checkout code
      uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4

    - name: Set image name
      id: image
      shell: bash
      run: |
        if [ -z "${{ inputs.image_name }}" ]; then
          echo "name=${{ github.repository }}" >> $GITHUB_OUTPUT
        else
          echo "name=${{ inputs.image_name }}" >> $GITHUB_OUTPUT
        fi

    - name: Set up Docker Buildx
      uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3

    - name: Log in to Container Registry
      uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9 # v3
      with:
        registry: ${{ inputs.registry }}
        username: ${{ inputs.registry_username || github.actor }}
        password: ${{ inputs.registry_password }}

    - name: Parse build args
      id: build-args
      shell: bash
      run: |
        if [ -n "${{ inputs.build_args }}" ]; then
          echo "args<<EOF" >> $GITHUB_OUTPUT
          echo "${{ inputs.build_args }}" | tr ',' '\n' >> $GITHUB_OUTPUT
          echo "EOF" >> $GITHUB_OUTPUT
        else
          echo "args=" >> $GITHUB_OUTPUT
        fi

    - name: Extract metadata
      id: meta
      uses: docker/metadata-action@c299e40c65443455700f0fdfc63efafe5b349051 # v5
      with:
        images: ${{ inputs.registry }}/${{ steps.image.outputs.name }}
        tags: |
          type=ref,event=pr,prefix=pr-
          type=sha,prefix=pr-{{branch}}-

    - name: Build and push PR image
      uses: docker/build-push-action@ca052bb54ab0790a636c9b5f226502c73d547a25 # v5
      with:
        context: ${{ inputs.docker_context }}
        file: ${{ inputs.dockerfile_path }}
        platforms: ${{ inputs.platforms }}
        push: true
        tags: ${{ steps.meta.outputs.tags }}
        labels: ${{ steps.meta.outputs.labels }}
        build-args: ${{ steps.build-args.outputs.args }}
        cache-from: type=gha
        cache-to: type=gha,mode=max

    - name: Comment PR with image tags
      uses: actions/github-script@f28e40c7f34bde8b3046d885e986cb6290c5673b # v7
      with:
        script: |
          const tags = `${{ steps.meta.outputs.tags }}`.split('\n');
          const comment = `### 🐳 Docker Image Built Successfully\n\n` +
            `**Image Tags:**\n${tags.map(tag => `- \`${tag}\``).join('\n')}\n\n` +
            `**Pull command:**\n\`\`\`bash\ndocker pull ${tags[0]}\n\`\`\``;
          
          github.rest.issues.createComment({
            issue_number: context.issue.number,
            owner: context.repo.owner,
            repo: context.repo.repo,
            body: comment
          });