14 Logging Observer Errors and Debugging Information

The observer writes error and debugging information to the following log files:

NanoAgentStartupErrors.log – contains configuration-related errors. This file is recreated on each restart of the server. The file will be empty if no errors were encountered. It's maximum size is 5 MB.

NanoAgent.log – contains runtime error and debugging information (you can adjust this logger's settings using the Enable trace logging option in the Observer Communication policy.)

AWTrace.log – contains trace-level messages. This file is created only for aspect-based observer probes and is recreated on each restart of the server. (All probes are aspect-based except for the JAX-RPC probe) The maximum size of this log file is 10 MB.


You can also configure the observer to log observed messages. For information on this topic, refer to the online help for information about the Log Observed Messages to File field in the Observer Communication policy.

The default location of the log files is:


The default log location for WCF and ASP.NET is not a true default. It is simply the default setting of the AmberPoint:NanoLogBaseDir key. If you set this key to null, log files will not be created.

If you want the log files generated in a different directory, set the AP_NANO_LOG_BASEDIR Java property or AmberPoint:NanoLogBaseDir Windows key. For Java application servers, you can set the property to either an absolute path or a path that is relative to the default log directory. For WCF and ASP.NET, you must set the key to an absolute path. The following examples illustrate how to set this property or key:

   <add key="AmberPoint:NanoConfig" value="c:/temp/NanoAgentLogBaseDir/nanoagentDiscovery.CONFIGURATION"/>
   <add key="AmberPoint:NanoLogBaseDir" value="c:/Inetpub/wwwroot/my_log_dir"/>
   <add key="AmberPoint:NanoCreateLogBaseDir" value="false"/>

In order for the observer to generate the log files, ensure that the user under which the observer is running has permission to write to the log directory. For Java observers, the user is the user that is running the application server. For IIS observers (WCF and ASP.NET), the user is as follows:

By default, the directory specified by the AP_NANO_LOG_BASEDIR property is automatically created if it does not exist. If you do not want this directory to be automatically created, set the property AP_NANO_CREATE_LOG_BASEDIR to false. In this case, you must create the directory yourself. Set this property in the same way you set AP_NANO_LOG_BASEDIR.


For Java application servers – If the log directory does not exist and AP_NANO_CREATE_LOG_BASEDIR is set to false, runtime errors might occur and the observer might not initialize.

For IIS – If the NanoAgentLogBaseDir Windows key set to null, log files are not created.