Monday, December 1, 2008

Extending Glassbox

Glassbox provides method-level diagnosis but the details are limited:
in the Glassbox UI, only the summarized listing of operations is shown.

However using JMX, break-up of each operation into it’s monitored nested operations and resource access if any, are displayed with average, max time and count, using Glassbox’s built-in monitors for important frameworks (includes servlets/jsp, struts, ejb calls with method name, jdbc calls with details of each prepared statement & more). So Glassbox by default would log your EJB calls, your database calls, your JSP calls, etc.

In spite of this, other details (like parameters for a request, method name in actual class used, etc) for the response to each monitored operation are recorded only if it fails some SLA. In addition, this does not anyway capture names of low-level classes or their methods.

But what if you wanted a customized Glassbox monitoring - what if you were not satisfied with just a high-level EJB call and wanted to see the actual classes and methods called?

There are 2 ways to do this:
1) Using a simple run-time configuration in an xml file, and with NO CODING
2) Much more powerful customization if you were willing to define custom Aspects and pointcuts.

This post will stick to the simple way using the xml file.
But I do want to highlight before you proceed that adding more detailed logging means more bloating of PermGen memory-usage (see here on how to increase PermGen). For example, even in Glassbox's built-in jsp monitor’s load-weaving, 1 loader is needed per Jsp, and each loader takes up 1MB.
Also, read this post about Glassbox setup first - see Steps to configure Glassbox for Sun App Server .

Ok let's see how to provide a detailed method level monitorining for all the classes in a package you specify.

First, create a file aop.xml with the following content:

<exclude within="org.springframework.jmx..*"/>
<!-- don't reweave -->
<exclude within="glassbox.inspector..*"/>
<concrete-aspect name="YourMonitor2"
<pointcut name="methodSignatureControllerExecTarget"

Next place this in a META-INF folder in any of the directories existing in your classpath.

That's it!
Next time you start up your server, Glassbox will monitor all the methods of all classes in the package,!

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