Exception "No default routing key has been configured for this direct exchange" when use conventional routing

[DmitriiBobrovskii1983]

Hello.

I try to use Wolverine with RabbitMq.

Currently my config for Wolverine is:

            var messageBusConfiguration = builder.Configuration.GetSection(nameof(MessageBusConfiguration)).Get<MessageBusConfiguration>();

            builder.UseWolverine(opts =>
            {
                opts.ApplicationAssembly = typeof(Program).Assembly;

                opts.UseRabbitMq(messageBusConfiguration!.ConnectionString)
                    .AutoProvision()
                    .EnableWolverineControlQueues()
                    .DisableDeadLetterQueueing()
                    .UseSenderConnectionOnly()
                    .ConfigureChannelCreation(o =>
                    {
                        o.PublisherConfirmationsEnabled = true;
                        o.PublisherConfirmationTrackingEnabled = true;
                        o.ConsumerDispatchConcurrency = 5;
                    })
                    .UseConventionalRouting(config =>
                    {
                       config.ExchangeNameForSending(type => "LoggerExchange")
                             .ConfigureSending((cfg, ctx) => cfg.ExchangeType(ExchangeType.Direct).UseDurableOutbox())
                             .OnlyApplyToOutboundMessages();
                    })
                    .BindExchange("LoggerExchange", c => c.ExchangeType = ExchangeType.Direct);

                opts.UseSystemTextJsonForSerialization();

                opts.DefaultExecutionTimeout = TimeSpan.FromMinutes(5);
                opts.DefaultRemoteInvocationTimeout = TimeSpan.FromMinutes(5);

                opts.Services.AddResourceSetupOnStartup();
            });

LoggerExchange is the durable Exchange created by me earlier manually.
So, each time I try to publish a message, for example, of Order class, I caught an error with message: "No default routing key has been configured for this direct exchange". I tried to use all possible variants, used manuals/docs/samples/tutorials from site, google, chatgpt, grok, but still have this issue.

Could you explain me, is this a bug or missunderstanding of ConventionalRouting? Thank you.

[jeremydmiller]

That's an unusual usage, and completely defeats the entire purpose of conventional routing if you just want every single message going to that one direct exchange. And why a direct exchange? I assume you googled and found that's a Rabbit MQ issue, right?

And yes, it's a misunderstanding of conventional routing. I don't think there's anything actionable here, so I'm converting this to a Discussion.

[DmitriiBobrovskii1983]

I'm a newbie in MessageQueues, and I just used RabbitMQ tutorials for better understanding different types of exchanges.

https://www.rabbitmq.com/tutorials/tutorial-four-dotnet

So, here I see, that direct exchange is an exchange with strict routing / binding name conventions. And I really try to realize the same architecture with one exchange and some subscribers who generates for each message type own queue with bindings to an exchange ("Putting it all together" schema on the page above).

Now I try to realize the same with Topic Exchange, but still no great progress - have no errors, but no messages received.
Could you explain a little which route key is generated under UseConventionalRouting schema for senders? Thank you.

This is better description about the problem: https://stackoverflow.com/questions/79893054/wolverinefx-conventional-routing-message-transfer-problem

But with the code

opts.PublishMessage<Order>().ToRabbitRoutingKey("LoggerExchange", typeof(Order).FullNameInCode(), c => c.ExchangeType = ExchangeType.Topic);

works well. So, really, what's the routing key for the Order? Why it's not possible to set routing key for sending types via conventional naming?

Also I should notice, that the code for IMessageRoutingConvention isn't working properly: the code under the section "Rolling Your own Messaging Convention" (https://wolverinefx.net/guide/messaging/subscriptions.html) always drops down with error: "Endpoint rabbitmq://exchange/LoggerExchange/routing/stocksharp.businessentities.order does not have an active sending agent. Message type: StockSharp.BusinessEntities.Order (Parameter 'endpoint')".