API Gateway untuk microservices architecture dengan rate limiting, authentication, request logging, dan load balancing.

API Gateway Service

A robust API Gateway implementation serving as the single entry point for microservices architecture.

Purpose

This gateway handles all incoming API requests, providing authentication, rate limiting, logging, and routing to appropriate microservices.

Key Capabilities

Security

Authentication Layer: JWT and API key validation
Authorization: Role-based access control (RBAC)
Rate Limiting: Token bucket algorithm implementation
IP Whitelisting: Restrict access by IP ranges
Request Validation: Schema-based input validation

Performance

Response Caching: Redis-based caching layer
Load Balancing: Round-robin and least-connections strategies
Circuit Breaker: Prevent cascading failures
Request Timeout: Configurable timeouts per route
Compression: Gzip compression for responses

Observability

Request Logging: Comprehensive request/response logging
Metrics Collection: Performance metrics with Prometheus
Health Checks: Monitor downstream services
Error Tracking: Centralized error reporting
Distributed Tracing: Track requests across services

Architecture

Gateway Structure

@Controller('api')
export class GatewayController {
  @UseGuards(JwtAuthGuard, RateLimitGuard)
  @Post('users')
  async createUser(@Body() dto: CreateUserDto) {
    // Validate request
    // Route to user microservice
    // Return response
  }
}

Rate Limiting Implementation

Using Redis for distributed rate limiting:

@Injectable()
export class RateLimitGuard implements CanActivate {
  async canActivate(context: ExecutionContext): Promise<boolean> {
    const req = context.switchToHttp().getRequest();
    const key = `rate_limit:${req.ip}`;
    
    const current = await this.redis.incr(key);
    if (current === 1) {
      await this.redis.expire(key, 60); // 1 minute window
    }
    
    return current <= 100; // 100 requests per minute
  }
}