MassTransit Bus.Publish calls SendObserver - masstransit

Question

I have noticed that when i call Bus.Publish my SendObserver is beeing called along with my PublishObserver. In my original scenario i use the observers for some debug logging where i noticed that when i call Publish both the PublishObserver and the SendObserver is called with the same message. The example code below reproduces the scenario:
public class YourMessage { public string Text { get; set; } }
public class SendObserver : ISendObserver {
public Task PreSend<T>(SendContext<T> context) where T : class
{
return Task.CompletedTask;
}
public Task PostSend<T>(SendContext<T> context) where T : class
{
Console.Out.WriteLineAsync($"Message Sent, Id: {context.MessageId}");
return Task.CompletedTask;
}
public Task SendFault<T>(SendContext<T> context, Exception exception) where T : class
{
return Task.CompletedTask;
}
}
public class PublishObserver : IPublishObserver
{
public Task PrePublish<T>(PublishContext<T> context) where T : class
{
return Task.CompletedTask;
}
public Task PostPublish<T>(PublishContext<T> context) where T : class
{
Console.Out.WriteLineAsync($"Message Published, Id: {context.MessageId}");
return Task.CompletedTask;
}
public Task PublishFault<T>(PublishContext<T> context, Exception exception) where T : class
{
return Task.CompletedTask;
}
}
public class Program
{
public static void Main()
{
var bus = Bus.Factory.CreateUsingRabbitMq(sbc =>
{
var host = sbc.Host(new Uri("rabbitmq://rabbitmq/PublishSendTest"), h =>
{
h.Username("guest");
h.Password("guest");
});
sbc.ReceiveEndpoint(host, "test_queue", ep =>
{
ep.Handler<YourMessage>(context =>
{
return Console.Out.WriteLineAsync($"Received: {context.Message.Text}");
});
});
});
bus.ConnectSendObserver(new SendObserver());
bus.ConnectPublishObserver(new PublishObserver());
bus.Start();
bus.Publish(new YourMessage { Text = "Hi" });
Console.WriteLine("Press any key to exit");
Console.ReadKey();
bus.Stop();
}
}
Output:
Press any key to exit
Message Sent, Id: ac4f0000-3051-1065-bbe5-08d6335c9e05
Message Published, Id: ac4f0000-3051-1065-bbe5-08d6335c9e05
Received: Hi
Is this the expected behaviour? If so what can i do to determine if it acutally was a Publish call that created the message?
I used version 5.1.5

Answer 1

The inconsistent observer issue should be resolved in the develop builds, and a test has been created to verify the behavior on the supported transports. Once released, the send observer should only be called on an actual Send, and the publish observer should only be called on an actual Publish.
Thanks for bringing this up, I'm not sure how it got out of whack.