PR Explainer Bot

A NestJS backend service that analyzes GitHub pull requests and provides a summary and risk assessment using Google's Gemini model.

Features

• Fetches PR diffs from GitHub
• Generates concise summaries of changes using Google's Gemini model
• Provides a risk score from 1 (low) to 5 (high)
• RESTful API endpoint for easy integration

Prerequisites

• Node.js (v18 or later)
• npm or yarn
• GitHub account with a personal access token
• Google Gemini API key

Setup

1. Clone the repository

   git clone https://github.com/yourusername/pr-explainer-bot.git
   cd pr-explainer-bot

2. Install dependencies

   npm install
   # or
   yarn

3. Set up environment variables Copy .env.example to .env and fill in your credentials:

   cp .env.example .env

   Edit the .env file with your GitHub token and Gemini API key:

   GITHUB_TOKEN=your_github_token_here
   GEMINI_API_KEY=your_gemini_api_key_here
   

4. Start the development server

   pnpm start:dev

   The API will be available at http://localhost:3000

API Endpoint

Generate PR Summary

POST /pr-summary
Content-Type: application/json

{
  "repo": "owner/repo",
  "pr_number": 123
}

Response

{
  "summary": "This PR refactors the authentication module to use JWT tokens...",
  "risk_score": 3
}

Environment Variables

Variable	Description	Required
GITHUB_TOKEN	GitHub personal access token with repo scope	Yes
GEMINI_API_KEY	Google Gemini API key	Yes
PORT	Port to run the server on (default: 3000)	No
NODE_ENV	Node environment (development/production)	No

Example cURL

curl -X POST http://localhost:3000/pr-summary \
  -H "Content-Type: application/json" \
  -d '{"repo":"facebook/react","pr_number":12345}'

Error Handling

The API returns appropriate HTTP status codes and error messages:

• 400 Bad Request: Invalid input data
• 404 Not Found: PR not found
• 401 Unauthorized: Missing or invalid GitHub token
• 500 Internal Server Error: Server error (check logs for details)

Development

• Run in development mode: pnpm start:dev
• Build for production: pnpm build
• Run tests: pnpm test
• Format code: pnpm format
• Lint code: pnpm lint

License

MIT