多个RabbitMQ交换和队列的DI配置

Question

I'm trying to configure DI for EventBusRabbitMQ implementation. It works perfectly fine for a single exchange, queue..

 services.AddSingleton<IEventBus, EventBusRabbitMQ>(serviceProvider =>
 {
     ...

     return new EventBusRabbitMQ(connection, "exchange_EX1", "queue_Q1",..);
 });

and in the application configuration

var eventBus = app.ApplicationServices.GetRequiredService<IEventBus>();

eventBus.Subscribe<FooEvent, FooEventHandler>;

I want to register multiple implementations with different configurations of EventBusRabbitMQ so i can pick and choose which exchange and queue to target when i resolve for IEventBus.

What i don't want is to be explicit about the implementations since the only thing that differs is just the exchange and queue.

services.AddSingleton<IEventBus, EventBusRabbitMQ_EX1_Q1>
services.AddSingleton<IEventBus, EventBusRabbitMQ_EX2_Q2>

what alternates do i have?

Answer 1

I think the best solution given you have a finit set of implementation is to consider a solution like this:

public interface  IEventBusRabbitMQ_EX1_Q1:IEventBus
{
}
public interface  IEventBusRabbitMQ_EX2_Q2:IEventBus
{
}

and then change your code to inject the right instance

services.AddSingleton<IEventBusRabbitMQ_EX1_Q1, EventBusRabbitMQ_EX1_Q1>
services.AddSingleton< IEventBusRabbitMQ_EX2_Q2, EventBusRabbitMQ_EX2_Q2>

But there is another solution which is described here

basically is an enricher kind pattern like but I don't recommend it because it reduces the readability of the code.