Auditing Messages

The distributed nature of parallel message-driven systems makes them more difficult to debug than their sequential, synchronous, and centralized counterparts. For these reasons, NServiceBus provides built-in message auditing for every endpoint. Just tell NServiceBus that you want auditing and it will capture a copy of every received message and forward it to a specified audit queue.

It is recommended that you specify a central auditing queue for all related endpoints (i.e. endpoints that belong to the same system). By doing so you can take advantage of central auditing within a distributed system. This is also required by the Particular Service Platform and especially ServiceControl, which consumes messages from these auditing queues. For more information, see ServicePulse documentation.

Handling Audit messages

What you choose to do with those messages is now up to you: save them in a database, do custom logging, etc. The important thing is that once you read the messages from the audit queue and process them, you have a centralized record of everything that is happening in your system while maintaining all the benefits of keep things distributed. It is important not to leave the messages in the audit queue however, as most queueing technologies have upper-bound limits on their queue sizes and depth. By not processing these messages you may find yourself reaching the limits of the underlying queue technology.

Audit configuration options

There two settings that control Auditing.

Queue Name

The queue name to forward audit messages to

OverrideTimeToBeReceived

You can force a TimeToBeReceived on audit messages by setting OverrideTimeToBeReceived using the configuration syntax below.

Note that while the phrasing is "forwarding a message" in the implementation it is actually "cloning and sending a new message". This is important when considering TimeToBeReceived since the time taken to receive and process the original message is not part of the TimeToBeReceived of the new audit message. So in effect the audit message receives the full time allotment of whatever TimeToBeReceived is used.

Default Value

If no OverrideTimeToBeReceived is defined then:

Version 5 and lower: TimeToBeReceived of the original message will be used.

Version 6 and higher: No TimeToBeReceived will be set.

Configuring auditing

Using Code

You can configure the target audit queue using the configuration API.

BusConfiguration busConfiguration = new BusConfiguration();
busConfiguration.AuditProcessedMessagesTo("targetAuditQueue");

Using app.config

<configuration>
  <configSections>
    <section name="UnicastBusConfig" 
             type="NServiceBus.Config.UnicastBusConfig, NServiceBus.Core"/>
  </configSections>
  <UnicastBusConfig 
    ForwardReceivedMessagesTo="auditqueue@adminmachine"/>
</configuration>
<configuration>
  <configSections>
    <section name="AuditConfig" 
             type="NServiceBus.Config.AuditConfig, NServiceBus.Core"/>
  </configSections>
  <AuditConfig QueueName="auditqueue@adminmachine"
               OverrideTimeToBeReceived="00:10:00"/>
</configuration>
<configuration>
  <configSections>
    <section name="AuditConfig" 
             type="NServiceBus.Config.AuditConfig, NServiceBus.Core"/>
  </configSections>
  <AuditConfig QueueName="auditqueue@adminmachine"
               OverrideTimeToBeReceived="00:10:00"/>
</configuration>
OverrideTimeToBeReceived needs to be a valid TimeSpan.

Using IProvideConfiguration

The audit settings can also be configured using code via a custom configuration provider

class ProvideConfiguration : IProvideConfiguration<AuditConfig>
{
    public AuditConfig GetConfiguration()
    {
        return new AuditConfig
        {
            QueueName = "auditqueue@adminmachine",
            OverrideTimeToBeReceived = TimeSpan.FromMinutes(10)
        };
    }
}
class ProvideConfiguration : IProvideConfiguration<AuditConfig>
{
    public AuditConfig GetConfiguration()
    {
        return new AuditConfig
        {
            QueueName = "auditqueue@adminmachine",
            OverrideTimeToBeReceived = TimeSpan.FromMinutes(10)
        };
    }
}

Machine level configuration

Version 4 and higher support setting the error queue and the audit queue at the machine level in the registry. Use the Set-NServiceBusLocalMachineSettings PowerShell commandlet to set these values at a machine level. When set at machine level, the setting is not required in the endpoint configuration file for messages to be forwarded to the audit queue.

Turning off auditing

If the auditing settings are in app.config, remove them or comment them out.

If the machine level auditing is turned on, clear the value for the string value AuditQueue under

HKEYLOCALMACHINE\\SOFTWARE\\ParticularSoftware\\ServiceBus

If running 64 bit, in addition to the above, also clear the value for AuditQueue under

HKEYLOCALMACHINE\\SOFTWARE\\Wow6432Node\\ParticularSoftware\\ServiceBus

Message headers

All headers, from the message being forwarded, will be included in the message sent to the audit queue. There are also some custom audit headers appended. See Message Headers for more information.

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Last modified 2016-01-11 14:00:26Z