【ChatGPT】GitHubプルリクエスト作成時に差分内容を要約して自動コメントする仕組みを作ってみた

comment-pr-summary-by-chatgpt.yml

name: comment-pr-summary-by-chatgpt

on:
  pull_request_target:
    types: [ opened, reopened ]

jobs:
  comment-pr-summary-by-chatgpt:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      pull-requests: write
    steps:
      #####
      # セットアップ
      #####
      - name: Switch to pull request branch
        uses: actions/checkout@v3
        with:
          ref: ${{ github.event.pull_request.head.sha }}

      - name: Fetch base branch
        run: |
          git fetch origin \
            ${{ github.event.pull_request.base.sha }}:BASE

      - name: Setup Python
        uses: actions/setup-python@v3
        with:
          python-version: '3.9'
          architecture: 'x64'

      - name: Install OpenAI
        run: |
          pip install -U openai

      #####
      # 更新されたファイル名一覧を取得
      #####
      - name: Get diff files
        run: |
          # ※特定拡張子にフィルタしています
          git diff --diff-filter=M --name-only HEAD BASE \
            | grep -e "\.md" -e "\.tf$" -e "\.yaml$" -e "\.py$" > _diff_files.txt
          cat _diff_files.txt

      #####
      # Run ChatGPT
      #####
      - name: run ChatGPT
        shell: bash {0}
        env:
          OPENAI_API_KEY: ${{secrets.OPENAI_API_KEY}}
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          URL: ${{ github.event.pull_request.html_url }}
        run: |
          # 各ファイルに対して「差分取得 -> 要約 -> PRコメント」を行う
          cat _diff_files.txt \
          | while read file_path;do
            echo "## summarize updates: ${file_path}"
            # 修正前テキスト, 修正後テキストの取得
            git cat-file -p BASE:${file_path} > _before.txt
            git cat-file -p HEAD:${file_path} > _after.txt
            # 差分の取得
            diff _before.txt _after.txt > _diff.txt | true
            cat _diff.txt
            # ChatGPTによる要約の取得
            chatgpt_response=$(python3 summarize_diff.py "${file_path}" "_diff.txt")
            echo "${chatgpt_response}"

            # GitHub PR へコメント
            echo "### :robot: ${file_path} の更新まとめ by ChatGPT

            ${chatgpt_response}" > _body.txt
            gh pr comment --body-file _body.txt "${URL}"
          done