docs_preview_deploy.yaml

# Copyright 2026 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

name: "Deploy Docs Preview"

on:
  workflow_run:
    workflows: ["Build Docs Preview"]
    types:
      - completed
  workflow_dispatch:
    inputs:
      pr_number:
        description: 'PR Number to deploy (Manual override)'
        required: true
        type: string
      build_run_id:
        description: 'The Run ID from the successful "Build Docs Preview" workflow'
        required: true
        type: string

permissions:
  contents: write
  pull-requests: write

jobs:
  deploy-preview:
    if: >
      github.event_name == 'workflow_dispatch' || 
      (github.event.workflow_run.event == 'pull_request' && github.event.workflow_run.conclusion == 'success')
    runs-on: ubuntu-24.04
    concurrency:
      group: "deploy-${{ github.event.inputs.pr_number || github.event.workflow_run.pull_requests[0].number }}"
      cancel-in-progress: true
    steps:
      - name: Checkout base repository
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6 

      - name: Download Artifact
        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8
        with:
          name: docs-preview-data
          github-token: ${{ secrets.GITHUB_TOKEN }}
          run-id: ${{ github.event.inputs.build_run_id || github.event.workflow_run.id }}
          path: downloaded-artifact

      - name: Read PR Number
        id: get_pr
        run: |
          if [ -n "${{ github.event.inputs.pr_number }}" ]; then
            PR_NUMBER="${{ github.event.inputs.pr_number }}"
          else
            PR_NUMBER=$(cat downloaded-artifact/pr_number.txt)
          fi
          
          if ! [[ "$PR_NUMBER" =~ ^[0-9]+$ ]]; then
            echo "Error: PR number [$PR_NUMBER] is invalid."
            exit 1
          fi
          
          echo "pr_number=$PR_NUMBER" >> "$GITHUB_OUTPUT"

      - name: Deploy
        uses: peaceiris/actions-gh-pages@4f9cc6602d3f66b9c108549d475ec49e8ef4d45e # v4
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          publish_dir: downloaded-artifact/public
          publish_branch: versioned-gh-pages
          destination_dir: ./previews/PR-${{ steps.get_pr.outputs.pr_number }}
          commit_message: "stage: PR-${{ steps.get_pr.outputs.pr_number }} preview"

      - name: Comment
        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8
        with:
          script: |
            const prNumber = parseInt('${{ steps.get_pr.outputs.pr_number }}', 10);
            
            await github.rest.issues.createComment({
              issue_number: prNumber,
              owner: context.repo.owner,
              repo: context.repo.repo,
              body: `🔎 Preview at https://${{ github.repository_owner }}.github.io/${{ github.event.repository.name }}/previews/PR-${prNumber}/`
            });