> For the complete documentation index, see [llms.txt](https://docs.nestjstools.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.nestjstools.com/best-practice/bootstrap-http-worker-mode.md).

# Bootstrap (Http, Worker mode)

#### 📘 Introduction

> A simple wrapper to speed up messaging-based app setup in NestJS.

[`@nestjstools/messaging-bootstrap`](https://www.npmjs.com/package/@nestjstools/messaging-bootstrap) It is a lightweight utility that simplifies bootstrapping a messaging-enabled NestJS application.

Built on top of [`@nestjstools/messaging`](https://www.npmjs.com/package/@nestjstools/messaging), it offers two main modes:

* An **HTTP server** with integrated messaging publisher capabilities
* A **dedicated worker/microservice** that runs only messaging consumers

***

#### ⚙️ Installation

```bash
yarn add @nestjstools/messaging-bootstrap @nestjs/microservices
```

***

#### 🚀 Quick Start

Create a file `messaging-confg.ts`

```typescript
// messaging-confg.ts

import { MessagingRabbitmqExtensionModule } from '@nestjstools/messaging-rabbitmq-extension';
import { AmqpChannelConfig, ExchangeType } from '@nestjstools/messaging';
import { MessagingModuleConfig } from '@nestjstools/messaging-bootstrap';

export const Config: MessagingModuleConfig = {
  extensions: [
    MessagingRabbitmqExtensionModule
  ],
  buses: [
    { name: 'command.bus', channels: ['async-command'] }
  ],
  channels: [
    new AmqpChannelConfig({
      name: 'async-command',
      connectionUri: 'amqp://localhost',
      exchangeName: 'command.exchange',
      bindingKeys: ['command.#'],
      exchangeType: ExchangeType.TOPIC,
      queue: 'app.command',
      enableConsumer: false,
    }),
  ],
};

```

**✅ HTTP Server with Messaging Publisher**

```ts
// main.ts
import { AppModule } from './app.module';
import { ConsoleLogger } from '@nestjs/common';
import { MessagingBootstrap } from '@nestjstools/messaging-bootstrap';
import { Config } from './messaging-confg';

async function bootstrap() {
  const app = await MessagingBootstrap.createNestApplicationWithMessaging(AppModule, {
    messaging: Config,
    nestApplicationOptions: {
      logger: new ConsoleLogger({ json: true }),
    },
  });
  await app.listen(3000);
}
bootstrap();

```

**✅ Worker/Microservice with Consumers**

```ts
// worker.ts
import { AppModule } from './app.module';
import { ConsoleLogger } from '@nestjs/common';
import { MessagingBootstrap } from '@nestjstools/messaging-bootstrap';
import { Config } from './messaging-confg';

async function bootstrap() {
  const app = await MessagingBootstrap.createNestMicroserviceWithMessagingConsumer(AppModule, {
    messaging: Config,
    nestMicroserviceOptions: {
      logger: new ConsoleLogger({ json: true }),
    },
  });
  await app.listen();
}
bootstrap();
```

***

#### 🛠️ 4. Configuration

All options are passed into the bootstrap function:

**`messaging` options:**

* `extensions`: array of messaging extension modules (e.g. RabbitMQ) (optional)
* `buses`: define one or more message buses
* `channels`: define channel configs (e.g. AMQP)

**`nestApplicationOptions` /** `nestMicroserviceOptions`**:**

* Directly passed to `NestFactory.create` or `createMicroservice`

***

#### 📄 5. Examples

**Shared Configuration Pattern**

```ts
export const messagingConfig = {
  extensions: [MessagingRabbitmqExtensionModule],
  buses: [{ name: 'command.bus', channels: ['async-command'] }],
  channels: [
    new AmqpChannelConfig({
      name: 'async-command',
      connectionUri: 'amqp://localhost',
      exchangeName: 'command.exchange',
      queue: 'app.command',
      bindingKeys: ['command.#'],
      exchangeType: ExchangeType.TOPIC,
      deadLetterQueueFeature: true,
      autoCreate: true,
      enableConsumer: false, // worker will auto-enable it
    }),
  ],
};
```

Then reuse in both `main.ts` and `worker.ts`.

***

#### ⚠️ 7. Common Pitfalls

**❌ Do not use `MessagingModule.forRoot()` manually**

> The bootstrap library already handles it for you. Including it manually will lead to **duplicate initialization** and **unexpected bugs**.

Correct usage:

```ts
// DO NOT DO THIS!
@Module({
  imports: [
    MessagingModule.forRoot({...}) // ❌ DON'T DO THIS
  ]
})
export class AppModule {}
```

Instead, let the bootstrap function handle it automatically.


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