Configure error handling

Configure the error queue address

When an endpoint fails to process a message successfully, NServiceBus automatically retries the message the configured number of times. If the message can not be processed successfully even after the retried attempts, NServiceBus forwards the message to a designated error queue.

When running with transport transactions disabled, NServiceBus will perform a best-effort error message forwarding, i.e. if moving to the error queue fails, the message will be lost.

When running with transport transactions disabled. Both immediate retries and delayed retries will be disabled automatically when transactions are turned off.

The default error queue name is error but some transports require it to be explicitly configured.

Using code

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endpointConfiguration.SendFailedMessagesTo("targetErrorQueue");

Configuring this feature via app.config, IConfigurationProvider, or IProvideConfiguration is deprecated in Version 7.

Error message header customizations

Before a message is moved to the error queue it is possible to inspect and modify its headers including error forwarding headers.

The following snippet shows how to configure header customizations and perform header value modification.

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var recoverability = endpointConfiguration.Recoverability();
recoverability.Failed(
    failed =>
    {
        failed.HeaderCustomization(headers =>
        {
            if (headers.ContainsKey("NServiceBus.ExceptionInfo.Message"))
            {
                headers["NServiceBus.ExceptionInfo.Message"] = "message override";
            }
        });
    });

Error queue monitoring

Administrators should monitor the error queue in order to detect when problems occur. The message in the error queue contains relevant information such as the endpoint that originally processed the message and exception details. With this information, an administrator can investigate the problem and solve it, for example, bringing up a database that went down.

Monitoring and handling of failed messages with ServicePulse provides access to full exception details including the stack-trace. ServiceInsight offers advanced debugging capability providing additional information like exception details as well as visualizing the flow of messages. Both ServiceInsight and ServicePulse provide retry functionality that sends a failed message from the error queue back to the originating endpoint for re-processing. For more details on how to retry a message using ServicePulse, see Introduction to Failed Messages Monitoring in ServicePulse. To retry a message using ServiceInsight, see Managing Errors and Retries in ServiceInsight.

If either ServicePulse or ServiceInsight are not available in the environment, the retry operation can be performed using the native management tools appropriate for the selected transport:

Configure the error queue address

Using code

Error message header customizations

Error queue monitoring

Samples

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