Why do I need to define queue name while creating microservice? - rabbitmq

Question

I want to have a hybrid NestJS app, HTTP + RabbitMQ. But don't get if I should create different microservices for each queue.
I have followed NestJS' RabbitMQ guide (https://docs.nestjs.com/microservices/rabbitmq) and GitHub example (https://github.com/nestjs/nest/tree/master/sample/03-microservices).
main.ts
app.connectMicroservice({
transport: Transport.RMQ,
options: {
urls: [`amqp://user:user#hostname:5672`],
queue: "cats_queue",
queueOptions: { durable: false },
prefetchCount: 1,
}
});
...
await app.startAllMicroservicesAsync();
app.module.ts (module import)
ClientsModule.register([{
name: "CATS_QUEUE", transport: Transport.RMQ, options: {
urls: [`amqp://user:user#hostname:5672`],
queue: "cats_queue",
queueOptions: { durable: false },
prefetchCount: 1
}
}])
app.controller.ts
constructor(
#Inject("CATS_QUEUE") private readonly client: ClientProxy
) {
}
#Get("mq")
mq(): Observable<number> {
const pattern = { cmd: "sum" };
const data = [1, 2, 3, 4, 5];
return this.client.send<number>(pattern, data);
}
#MessagePattern({ cmd: "sum" })
sum(data: number[]): number {
console.log("MESSAGE RECEIVED : " + data.toString());
return (data || []).reduce((a, b) => a + b);
}
As I understood, I need to define ClientsModule.register() for each queue in app.module.ts. But why I also need to define RabbitMQ queue name while creating microservice? Do I need to create different microservices for each queue?

Answer 1

I'm not a NestJS user, but it seems logical that when you use queues to send messages between your microservices, you will need a queue for each microservice (not the other way around).
Queues are used to send (TO) and receive(Process) messages between independent components asynchronously.
Does that make sense?