NestJS Messaging Module

This is an npm package for managing messaging in NestJS applications. It provides a way to configure messaging options and send messages from different services in your NestJS application.

Installation

You can install this package using npm or yarn:

npm install @aiondigital/messaging-queues
# or
yarn add @aiondigital/messaging-queues

Usage/Examples

To configure the module globally, you can use the MessagingModule.forRootAsync method. This allows you to set up the messaging options for your application.

import { MessagingModule } from '@aiondigital/messaging-queues';
import { ConfigurationService } from './configuration.service';

@Module({
  imports: [CommonModule],
  imports: [
    MessagingModule.forRootAsync({
      useFactory: (_config: ConfigurationService) => {
        return _config.MESSAGING_OPTIONS;
      },
      inject: [ConfigurationService],
    }),
  ],
})
export class YourModule {}

The MESSAGING_OPTIONS object should have the following fields:

• expirationSeconds (optional): A number specifying message expiration time.
• deadLetterExchange: The name of the dead-letter exchange.
• deadLetterQueue: The name of the dead-letter queue.
• brokerType: A value representing the broker type (e.g., "redis" or "rabbitmq").
• rabbitmq (optional): Additional configuration for RabbitMQ, if brokerType is set to "rabbitmq".
• redis (optional): Additional configuration for Redis, if brokerType is set to "redis".

Sending Messages

You can send messages from different services in your NestJS application using the MessagingService. First, you need to register a queue:

import { MessagingModule } from '@aiondigital/messaging-queues';

@Module({
  imports: [MessagingModule.registerQueue({
    name: ROUTING_KEYS.ADD_AUDIT_LOG,
    exchangeName: EXCHANGE.AUDIT,
  })],
})
export class YourModule {}

Then, in your service, you can use the MessagingService to send messages:

import { Injectable } from '@nestjs/common';
import { MessagingService } from '@aiondigital/messaging-queues';

@Injectable()
export class YourService {
  constructor(private readonly messagingService: MessagingService) {}

  sendLogs(input) {
    this.messagingService.sendMessage(ROUTING_KEYS.ADD_AUDIT_LOG, input);
  }
}

That's it! You've now set up global configuration for the messaging module and can use the MessagingService to send messages from your NestJS services.

Message Processing

Class-Level Decorator

At the class level, you can use the @Processor decorator to specify which routing key this class will be responsible for processing. Here's how you can use it:

import { Processor } from '@aiondigital/messaging-queues';

@Processor(ROUTING_KEYS.ADD_AUDIT_LOG)
export class YourMessageProcessor {
  // Your message processing methods go here
}

Function-Level Decorator

For individual message processing methods, you can use the @Process decorator to specify the details of the message processing. Here's how you can use it:

import { Process } from '@aiondigital/messaging-queues';
import { CreateAuditLogInput } from './create-audit-log.dto';

@Process({
  name: '', // Give it a unique name
  exchangeName: EXCHANGE.AUDIT,
  routingKey: ROUTING_KEYS.ADD_AUDIT_LOG,
})
async auditlog(data: CreateAuditLogInput, done: AckCallback) {
  // Your message processing logic here
  try {
    const audit = await this.auditService.create(data, ['id']);
    return audit;
  } catch (error) {
    this.#logger.error(`Failed to add audit log: [${JSON.stringify(data)}]`);
    this.#logger.error(error);
    done(error);
  }
}

You should place the @Process decorator on methods that will process messages with a specific routing key. You can have multiple methods with different routing keys within the same class.

Remember to replace the placeholders (ROUTING_KEYS.ADD_AUDIT_LOG, EXCHANGE.AUDIT, etc.)` with the actual values from your application.

Now, the YourMessageProcessor class will process messages with the routing key specified in the @Processor decorator, and the auditlog method will handle messages with the routing key specified in the @Process decorator.

License

This package is released under the MIT License