Custom Exception Handling

Component: NServiceBus
NuGet Package NServiceBus (8-pre)
This page targets a pre-release version. Pre-releases are subject to change and samples are not guaranteed to be fully functional.

This sample shows how, based on the exception type, a message can be either retried, sent to the error queue, or ignored. The portable Particular Service Platform will list the messages arriving in the error queue.

This sample includes a portable version of the Particular Service Platform tools. These tools are available only on Windows environments but are not necessary to run the sample.

In Versions 6 and above, the IManageMessageFailures is deprecated and there's no direct way to manage custom exceptions. The Recoverability API allows for much easier configuration of immediate and delayed retries. However finer-grain control can be achieved by writing a custom Behavior and having it executed as step in the message handling pipeline.

public override async Task Invoke(ITransportReceiveContext context, Func<Task> next)
        await next()
    catch (MyCustomException)
        // Ignore the exception, avoid doing this in a production code base
        Log.WarnFormat("MyCustomException was thrown. Ignoring the error for message Id {0}.", context.Message.MessageId);
    catch (MessageDeserializationException deserializationException)
        // Custom processing that needs to occur when a serialization failure occurs.
        Log.Error("Message deserialization failed", deserializationException);
    catch (Exception ex)
        //Throwing will eventually send the message to the error queue
        Log.Error("Message failed.", ex);

To register the new exception handler:

var pipeline = endpointConfiguration.Pipeline;
    behavior: new CustomErrorHandlingBehavior(),
    description: "Manages thrown exceptions instead of delayed retries.");

Beware of swallowing exceptions though, since it is almost never intended and the message will be removed from the queue, as if it has been processed successfully.

Related Articles

Last modified