# Starting the Python Service

## Quick Start

```bash
cd backend/python_service
uvicorn main:app --reload --port 8000
```

## Using Virtual Environment (Recommended)

If you want to use a virtual environment (recommended for isolation):

```bash
# Create virtual environment
cd backend/python_service
python -m venv venv

# Activate (Windows)
venv\Scripts\activate

# Activate (macOS/Linux)
source venv/bin/activate

# Install dependencies
pip install -r requirements.txt

# Start service
uvicorn main:app --reload --port 8000
```

## Verify Service is Running

Once started, you should see:
```
INFO:     Uvicorn running on http://127.0.0.1:8000
INFO:     Application startup complete.
```

Test the health endpoint:
```bash
curl http://localhost:8000/health
```

Expected response:
```json
{
  "status": "healthy",
  "service": "options-flow-processor"
}
```

## Troubleshooting

### ModuleNotFoundError
- Make sure you've run: `pip install -r requirements.txt`
- If using venv, make sure it's activated
- Check Python version: `python --version` (should be 3.11+)

### Port Already in Use
- Change port: `uvicorn main:app --reload --port 8001`
- Update `PYTHON_SERVICE_URL` in Node.js `.env` to match

### Database Connection Error
- Check `.env` file has correct database credentials
- Verify PostgreSQL is running
- Test connection: `psql -h localhost -U postgres -d institutional_trader`

## Next Steps

Once the Python service is running:
1. Start Node.js backend: `cd backend && npm run dev`
2. Node.js will automatically detect and use Python service
3. Check logs to confirm: `✅ Using Python service`