Assist_Design/LOGGING_USAGE.md

# Simple Centralized Logging

## ✅ **Single Pino Logger Everywhere**

We now use **one simple Pino logger** across the entire application:

- **Frontend (Portal)**: Uses the same Pino logger
- **Backend (BFF)**: Uses `nestjs-pino` with the same configuration
- **Shared**: Single logger configuration

## 🚀 **Usage Examples**

### **Frontend (Portal)**

```typescript
import { logger, log } from "@/lib/logger";

// Simple logging
log.info("User logged in", { userId: "123" });
log.error("API call failed", error);

// Direct Pino usage
logger.info({ userId: "123" }, "User logged in");
```

### **Backend (BFF) - Dependency Injection**

```typescript
import { Logger } from "nestjs-pino";

@Injectable()
export class UserService {
  constructor(@Inject(Logger) private readonly logger: Logger) {}

  async findUser(id: string) {
    this.logger.info({ userId: id }, "Finding user");
  }
}
```

### **Backend (BFF) - Direct Import**

```typescript
import { logger, log } from "@customer-portal/domain";

// Simple logging
log.info("Service started");
log.error("Database error", error);

// Direct Pino usage
logger.info({ userId: "123" }, "User action");
```

## 🔧 **Configuration**

All configuration is in one place: `packages/shared/src/logger.ts`

- **Development**: Pretty printed logs with colors
- **Production**: JSON logs for log aggregation
- **Browser**: Console-friendly output
- **Security**: Automatic redaction of sensitive fields

## 🎯 **Benefits**

- ✅ **One logger** instead of multiple complex systems
- ✅ **Same configuration** everywhere
- ✅ **No more fs/promises errors**
- ✅ **Simple imports** - just `import { log } from "@customer-portal/domain"`
- ✅ **Production ready** with automatic security redaction