Health checks và graceful shutdown trong NestJS production?

import { TerminusModule, TypeOrmHealthIndicator, HealthCheckService, MicroserviceHealthIndicator } from '@nestjs/terminus';
import { Transport, RedisOptions } from '@nestjs/microservices';
// Lưu ý: HealthController là controller do user tạo, không phải từ @nestjs/terminus.

@Module({ imports: [TerminusModule] })
export class HealthModule {}

// controller
@Get('health')
@HealthCheck()
check() {
  return this.health.check([
    () => this.db.pingCheck('database'),
    // Redis không nói HTTP — ping bằng MicroserviceHealthIndicator, không phải HttpHealthIndicator
    () => this.microservice.pingCheck<RedisOptions>('redis', {
      transport: Transport.REDIS,
      options: { host: 'redis', port: 6379 },
    }),
    () => this.memory.checkHeap('memory_heap', 300 * 1024 * 1024),
  ]);
}

// main.ts
app.enableShutdownHooks(); // Lắng nghe SIGTERM, SIGINT

// Service có thể implement OnApplicationShutdown
async onApplicationShutdown(signal?: string) {
  this.logger.log(`Shutting down on signal: ${signal}`);
  await this.closeConnections();
}