# Token Storage Configuration

The application automatically detects and uses the appropriate token storage backend based on environment variables.

## In-Memory Storage (Default)

By default, tokens are stored in memory. This is suitable for:

- Development
- Single-instance deployments
- Testing

**No configuration needed** - this is the default behavior.

## Redis Storage (Production Recommended)

For production deployments with multiple instances, use Redis for shared token storage.

### Setup

1. **Install Redis dependency:**

   ```bash
   uv sync --extra redis
   # or
   pip install redis>=5.0.0
   ```

2. **Set environment variable:**

   ```bash
   export REDIS_URI=redis://localhost:6379/0
   ```

3. **Start the application:**
   The app will automatically detect Redis and use it for token storage.

### Docker Compose with Redis

Uncomment the Redis service in `docker-compose.yml`:

```yaml
services:
  app:
    environment:
      - REDIS_URI=redis://redis:6379/0

  redis:
    image: redis:7-alpine
    volumes:
      - redis-data:/data

volumes:
  redis-data:
```

Then run:

```bash
docker compose up
```

### Verification

On startup, the application will print:

- `✓ Connected to Redis at redis://...` - Using Redis
- `ℹ Using in-memory token storage` - Using in-memory

### Error Handling

**Important**: If `REDIS_URI` is set, the application **requires** a successful Redis connection. It will **not** fall back to in-memory storage.

If Redis connection fails, the application will exit with a clear error message:

```
RuntimeError: Failed to connect to Redis at redis://localhost:6379.
Ensure Redis is running and accessible.
```

This prevents silent failures in production environments where Redis is expected.

### Benefits of Redis

- ✅ **Shared storage** across multiple app instances
- ✅ **Automatic expiration** with TTL
- ✅ **Persistent** (with proper Redis configuration)
- ✅ **Scalable** for high-traffic applications
- ✅ **Drop-in replacement** - no code changes needed