Google OAuth Setup Guide

To enable user authentication via Google in the Identity Service, you need to create OAuth 2.0 Client IDs on the Google Cloud Platform.

Step 1: Create a Project on Google Cloud

1. Go to the Google Cloud Console.
2. Click the project dropdown in the top-left -> New Project.
3. Enter a Project Name (e.g., LangEval Auth) -> Click Create.

Step 2: Configure OAuth Consent Screen

1. In the left menu, select APIs & Services > OAuth consent screen.
2. Choose External (to allow anyone to log in) or Internal (if restricted to your organization).
3. Click Create.
4. Fill in the required information:
   • App name: LangEval
   • User support email: Your email address.
   • Developer contact information: Your email address.
5. Click Save and Continue through the Scopes and Test Users steps (defaults are usually fine).

Step 3: Create Credentials

1. Go to the APIs & Services > Credentials menu.
2. Click + CREATE CREDENTIALS > OAuth client ID.
3. Application type: Select Web application.
4. Name: LangEval Web Client.
5. Authorized JavaScript origins:
   • http://localhost:3000 (Development)
   • https://langeval.space (Production - Vercel)
6. Authorized redirect URIs:
   • http://localhost:3000/api/auth/callback/google
   • https://langeval.space/api/auth/callback/google (Production)
7. Click Create.

Step 4: Configure Environment Variables

4.1 For Identity Service (Backend)

Update your .env file or Docker configuration:

env
GOOGLE_CLIENT_ID=your-client-id.apps.googleusercontent.com
GOOGLE_CLIENT_SECRET=your-client-secret

4.2 For Langeval UI (Frontend - Vercel)

To make NextAuth work on Vercel, you MUST configure the following environment variables in Settings > Environment Variables: