NServiceBus.SRL

A plugin to NServiceBus that allows configuration of Second Level Retries based on the Exception Type.

Configuration Options

We can specify these options for any exception type that may be thrown by our handler. We are commonly referring to these options as RetryAttemptSettings

Number of retries - Defines the number of Second Level Retry attempts made for messages throwing this particular exception. This is defined with the As(int) method

Incrementing - Defines the TimeSpan by which we increment subsequent retries for this message This is defines with the IncrementingEachBy(TimeSpan) method

Registration with NServiceBus

The package is set up to be automatically pulled into NServiceBus and register itself.

How to Configure

Once we pull the package into our endpoint project, we can configure our SLR's within the endpoint configuration like so:

    public class EndpointConfig : IConfigureThisEndpoint, AsA_Server, IWantCustomInitialization
    {
        public void Init()
        {
            Define.Retries.For<DivideByZeroException>().As(5).IncrementingEachBy(TimeSpan.FromSeconds(5));	            

            // Other NServiceBus Configuration

        }
    }

This defines a SLR for a DivideByZeroException, defining 5 retries for this exception, incrementing each retry by 5 seconds.

Global SLR Configuration

The global configuration will apply to any exception which is not specifically defined. This acts as the default. We can change the default in a couple different ways:

By defining a rule for the System.Exception:

    public class EndpointConfig : IConfigureThisEndpoint, AsA_Server, IWantCustomInitialization
    {
        public void Init()
        {
            Define.Retries.For<Exception>().As(3).IncrementingEachBy(TimeSpan.FromSeconds(1));	            

            // Other NServiceBus Configuration

        }
    }

By using the Default:

    public class EndpointConfig : IConfigureThisEndpoint, AsA_Server, IWantCustomInitialization
    {
        public void Init()
        {
            Define.Retries.Default.As(3).IncrementingEachBy(TimeSpan.FromMinutes(1));	            

            // Other NServiceBus Configuration

        }
    }

Disabling SLR by exception:

You can also disable SLR for a particular exception. This is useful if you have a default set, but for some particular exception you do not want to retry. This is done like so:

    public class EndpointConfig : IConfigureThisEndpoint, AsA_Server, IWantCustomInitialization
    {
        public void Init()
        {
            Define.Retries.Default.As(3).IncrementingEachBy(TimeSpan.FromMinutes(1));	            
            Define.Retries.For<System.DivideByZeroException>().Disable();

            // Other NServiceBus Configuration

        }
    }

This will enable a default SLR configuration, yet disable SLR for a System.DivideByZeroException