OnModuleDestroy

Kind: Interface

Source: packages/common/interfaces/hooks/on-destroy.interface.ts

Part of: Common

Interface defining method called just before Nest destroys the host module (app.close() method has been evaluated). Use to perform cleanup on resources (e.g., Database connections).

OnModuleDestroy is a Nest lifecycle interface for providers, controllers, and modules that need to release resources before their host module is destroyed. Nest invokes onModuleDestroy() after app.close() begins shutdown, making it suitable for closing database connections, stopping background workers, or clearing external clients.

Diagram

mermaid
graph LR
  A[Application calls app.close()] --> B[Nest starts module shutdown]
  B --> C[Provider implements OnModuleDestroy]
  C --> D[onModuleDestroy() is invoked]
  D --> E[Release resources<br/>close connections / stop workers]
  E --> F[Host module is destroyed]

Usage

ts
import { Injectable, OnModuleDestroy } from '@nestjs/common';

@Injectable()
export class DatabaseService implements OnModuleDestroy {
  private readonly connection = createDatabaseConnection();

  async onModuleDestroy(): Promise<void> {
    await this.connection.close();
  }
}

function createDatabaseConnection() {
  return {
    async close() {
      console.log('Database connection closed');
    },
  };
}

AI Coding Instructions

• Implement OnModuleDestroy on injectable providers that own resources requiring explicit cleanup.
• Define an onModuleDestroy() method; it may be synchronous or return a Promise.
• Close only resources owned by the current provider, such as database clients, message consumers, or timers.
• Make cleanup safe to run once and avoid throwing unnecessary errors during application shutdown.
• Ensure shutdown is initiated through app.close() so Nest can invoke lifecycle hooks.

Used by

4 references from 4 files. Each is a place in this repository where the symbol is actually used — go read one rather than trusting an example.

Imported by (4)

• KafkaController — integration/microservices/src/kafka/kafka.controller.ts:15
• KafkaConcurrentController — integration/microservices/src/kafka-concurrent/kafka-concurrent.controller.ts:24
• DatabaseConnection — integration/repl/src/database/database.connection.ts:3
• callModuleDestroyHook — packages/core/hooks/on-module-destroy.hook.ts:41