name: Publish DockerImage from Release Branch

on:
  workflow_dispatch:
    inputs:
      releaseBranch:
        description: 'Release Branch (releases/mXXX)'
        required: true

jobs:
  publish-image:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
      id-token: write
      attestations: write
    env:
      REGISTRY: ghcr.io
      IMAGE_NAME: ${{ github.repository_owner }}/actions-runner
    steps:
      - name: Checkout repository
        uses: actions/checkout@v6
        with:
          ref: ${{ github.event.inputs.releaseBranch }}

      - name: Compute image version
        id: image
        uses: actions/github-script@v8
        with:
          script: |
            const fs = require('fs');
            const runnerVersion = fs.readFileSync('${{ github.workspace }}/releaseVersion', 'utf8').replace(/\n$/g, '');
            console.log(`Using runner version ${runnerVersion}`);
            if (!/^\d+\.\d+\.\d+$/.test(runnerVersion)) {
              throw new Error(`Invalid runner version: ${runnerVersion}`);
            }
            core.setOutput('version', runnerVersion);

      - name: Setup Docker buildx
        uses: docker/setup-buildx-action@v3

      - name: Log into registry ${{ env.REGISTRY }}
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Build and push Docker image
        id: build-and-push
        uses: docker/build-push-action@v6
        with:
          context: ./images
          platforms: |
            linux/amd64
            linux/arm64
          tags: |
            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ steps.image.outputs.version }}
            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest
          build-args: |
            RUNNER_VERSION=${{ steps.image.outputs.version }}
          push: true
          labels: |
            org.opencontainers.image.source=${{github.server_url}}/${{github.repository}}
            org.opencontainers.image.licenses=MIT
          annotations: |
            org.opencontainers.image.description=https://github.com/actions/runner/releases/tag/v${{ steps.image.outputs.version }}

      - name: Generate attestation
        uses: actions/attest-build-provenance@v3
        with:
          subject-name: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          subject-digest: ${{ steps.build-and-push.outputs.digest }}
          push-to-registry: true