> 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/configuration.md).

# Configuration

`MessagingModule` can be configured using `MessagingModule.forRoot()`.

This configuration defines:

* **buses** – logical message buses used by your application
* **channels** – transports responsible for delivering messages
* **debug and logging behavior**
* **consumer execution rules**

Example configuration:

```ts
import { MessagingModule, InMemoryChannelConfig } from '@nestjstools/messaging';

MessagingModule.forRoot({
  buses: [
    {
      name: 'event.message-bus',
      channels: ['in-memory-channel'],
    },
  ],
  channels: [
    new InMemoryChannelConfig({
      name: 'in-memory-channel',
    }),
  ],
  debug: false,
  logging: true,
});
```

***

## MessagingModule.forRoot Options

| Property                   | Description                                                                                                               | Default      |
| -------------------------- | ------------------------------------------------------------------------------------------------------------------------- | ------------ |
| `buses`                    | Array of message buses defining routing and processing of messages.                                                       | `[]`         |
| `channels`                 | Array of channel configurations used by the message buses.                                                                | `[]`         |
| `debug`                    | Enables debug mode with additional logs useful during development.                                                        | `false`      |
| `logging`                  | Enables logging for bus activity (e.g., message dispatching).                                                             | `true`       |
| `customLogger`             | Custom logger instance implementing `MessagingLogger`.                                                                    | `NestLogger` |
| `forceDisableAllConsumers` | Disables all external consumers. Messages will only be processed using `InMemoryChannel`. Useful in testing environments. | `false`      |

***

## Buses

A **bus** defines how messages are routed through your system.

You can create multiple buses for different responsibilities, for example:

* command bus
* event bus
* query bus

#### Bus configuration

| Property   | Description                             | Default |
| ---------- | --------------------------------------- | ------- |
| `name`     | Unique name of the message bus.         | —       |
| `channels` | List of channel names used by this bus. | `[]`    |

Example:

```ts
buses: [
  {
    name: 'command.message-bus',
    channels: ['rabbitmq-channel'],
  },
  {
    name: 'event.message-bus',
    channels: ['rabbitmq-channel', 'in-memory-channel'],
  },
];
```

***

## Channels

Channels represent **transport layers** responsible for delivering and receiving messages.

Examples of transports:

* RabbitMQ
* Redis
* NATS
* Google Pub/Sub
* In-memory messaging

Each channel has its own configuration.

***

## InMemoryChannelConfig

The `InMemoryChannelConfig` is the simplest channel implementation and is useful for:

* development
* testing
* synchronous message execution

#### Properties

| Property                           | Description                                                           | Default            |
| ---------------------------------- | --------------------------------------------------------------------- | ------------------ |
| `name`                             | Name of the in-memory channel.                                        | —                  |
| `middlewares`                      | List of middlewares applied to messages passing through this channel. | `[]`               |
| `avoidErrorsForNotExistedHandlers` | Prevent errors when no handler exists for a message.                  | `false`            |
| `normalizer`                       | Custom message normalizer used before dispatching messages.           | Default normalizer |

Example:

```ts
channels: [
  new InMemoryChannelConfig({
    name: 'in-memory-channel',
    middlewares: [],
  }),
];
```


---

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