Lifecycle Interfaces

Interfaces for application and module lifecycle hooks.

OnModuleInit

Called after module providers are resolved.

interface OnModuleInit {
  onModuleInit(): any;
}

@Injectable()
export class DatabaseService implements OnModuleInit {
  async onModuleInit() {
    await this.connect();
    console.log('Database connected');
  }
}

OnModuleDestroy

Called before module is destroyed.

interface OnModuleDestroy {
  onModuleDestroy(): any;
}

@Injectable()
export class DatabaseService implements OnModuleDestroy {
  async onModuleDestroy() {
    await this.disconnect();
    console.log('Database disconnected');
  }
}

OnApplicationBootstrap

Called after all modules are initialized.

interface OnApplicationBootstrap {
  onApplicationBootstrap(): any;
}

@Injectable()
export class CacheWarmupService implements OnApplicationBootstrap {
  async onApplicationBootstrap() {
    await this.warmupCache();
    console.log('Cache warmed up');
  }
}

OnApplicationShutdown

Called on application shutdown.

interface OnApplicationShutdown {
  onApplicationShutdown(signal?: string): any;
}

@Injectable()
export class CleanupService implements OnApplicationShutdown {
  async onApplicationShutdown(signal?: string) {
    console.log(`Shutting down on signal: ${signal}`);
    await this.cleanup();
  }
}

BeforeApplicationShutdown

Called before shutdown hooks.

interface BeforeApplicationShutdown {
  beforeApplicationShutdown(signal?: string): any;
}

@Injectable()
export class GracefulShutdownService implements BeforeApplicationShutdown {
  async beforeApplicationShutdown(signal?: string) {
    await this.stopAcceptingRequests();
    await this.waitForPendingRequests();
  }
}

Lifecycle Order

1. OnModuleInit (per module, depth-first)
2. OnApplicationBootstrap (all providers)
3. Application runs...
4. BeforeApplicationShutdown (all providers)
5. OnApplicationShutdown (all providers)
6. OnModuleDestroy (per module, reverse order)

Enabling Shutdown Hooks

const app = await BunFactory.create(AppModule);
app.enableShutdownHooks();
await app.listen(3000);