MassTransit failing to consume - masstransit

Question

I'm switching some code which uses MassTransit (v7.2.2 on .NET 5) to use a more declarative format (and away from multiple calls to ReceiveEndpoint()) and ideally to using ConsumerDefinitions for the configuration (though not part of this example for simplicity), along with some Dependency Injection with Quartz.NET (yanked from this example, though it running 3.3.3), in doing so I find now that my Consumers are not consuming, despite messages being sent and examples referenced. Take the following standing up of the MassTransit service:
var hostBuilder = Host.CreateDefaultBuilder(args)
.ConfigureServices((hostContext, services) =>
{
services.AddMassTransit(mt =>
{
mt.AddBus(provider => Bus.Factory.CreateUsingInMemory(cfg =>
{
//cfg.AutoStart = true; //No change when on
cfg.UseInMemoryOutbox();
cfg.ConfigureEndpoints(provider);
}));
mt.AddConsumer<TheMessageConsumer>();
services.AddMediator(cfg =>
{
cfg.AddConsumer<TheMessageConsumer>();
});
});
services.AddMassTransitHostedService();
});
var host = hostBuilder.Build();
var busControl = host.Services.GetService<IBusControl>();
busControl.Start(); //Just in case
var message = new TheMessage() { Message = $"<Message-{DateTime.Now.ToLongTimeString()}>" };
Console.WriteLine($"Sending: {message.Message}");
await busControl.Publish(message);
host.Run();
For note, the breaking out of the message sending here is to simplify my repro, as in my full code base, it's being sent by a Quartz fired job.
For this example, the message & receiver are also quite simple:
public class TheMessage
{
public string Message { get; set; }
}
public class TheMessageConsumer : IConsumer<TheMessage>
{
public Task Consume(ConsumeContext<TheMessage> context)
{
Console.WriteLine($"Message received: {context.Message.Message}");
return Task.CompletedTask;
}
}
The bus is started, either in the case I explicitly start it, the AutoStart flag is set, or the MassTransitHostedService does it, yet the message doesn't get received. Ditto if I have the full example with Quartz firing off a job with messages much later.
Can someone suggest what I am missing?

Answer 1

The code you posted is seriously a hodgepodge of snippets, none of which make any sense when used together. For example, AddBus is deprecated, and mediator has no business being in that project at all.
I'd suggest using one of the MassTransit Templates to create a new project from scratch (you may need to up the NuGet versions to 7.2.2).
Watch this video which explains the templates and how to use them.
With your comment, and updated question, you really only need the following:
var hostBuilder = Host.CreateDefaultBuilder(args)
.ConfigureServices((hostContext, services) =>
{
services.AddMassTransit(mt =>
{
mt.AddConsumer<TheMessageConsumer>();
mt.UsingInMemory((context,cfg) =>
{
cfg.UseInMemoryOutbox();
cfg.ConfigureEndpoints(context);
}));
});
services.AddMassTransitHostedService();
});
var host = hostBuilder.Build();
await host.RunAsync();
If you want to test it, and send messages in the same process, simply add a BackgroundService (after AddMassTransitHostedService) to publish your messages.
You shouldn't publish until after the bus has been started.