Using WLDF to trace the time taken by your methods

WLDF stands for WebLogic Diagnostic Framework.

It's shipped within WebLogic Server and allow three types of features to help you diagnose your application and/or server :

• => Collected Metrics
• => Watch & Notification
• => Instrumentation

We're going to focus on the AOP feature, commonly known as "Instrumentation".

I assume you're familiar with AOP concepts.

 

Sample Application : presentation

 

Our application is composed of three classes, calling each other the following way :

Component1 -> Component2 -> Component3

Each call will be delayed by a pause, in order to be able to observe some concrete data later.

 

 

For instance, here's the code for Component1 :

 

package fr.mbutton.blog.wldf;

/**
* @author mbutton
*
*/
public class Component1 implements CallerInterface {
    public void call () {
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        CallerInterface comp = new Component2();
        comp.call();
    }

}

 

Configuring WLDF

 

From the application point of view

 

The configuration is pretty easy. It is embodied in a file weblogic-diagnostics.xml, which resides in the META-INF directory.

(I have chosen application scope, but you may chose the server scope. This is discussed in the official documentation)

 

 

Here's the content of this file :

 

<wldf-resource xmlns="http://www.bea.com/ns/weblogic/90/diagnostics"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.bea.com/ns/weblogic/90/diagnostics.xsd">
    <name>Sample WLDF resource</name>
    <instrumentation>
        <enabled>true</enabled>
        <wldf-instrumentation-monitor>
            <name>sample</name>
            <enabled>true</enabled>
            <action>TraceElapsedTimeAction</action>
            <location-type>around</location-type>
            <pointcut>execution( * fr.mbutton.blog.wldf.* call*(...));</pointcut>
        </wldf-instrumentation-monitor>
    </instrumentation>
</wldf-resource>

 

Let's take a closer look to the tags :

• => enabled : has obviously to be set to true :) for both instrumentation & monitor
• => name : has to be unique
• => action : the action that has to be performed. Can be one of the following :

  DisplayArgumentsAction
  StackDumpAction
  ThreadDumpAction
  TraceAction
  TraceElapsedTimeAction

• => location-type : before / after / around
• => pointcut : the kind of execution on which the AOP behavior has to be performed

For more information, as usual, take a look at the official documentation.

 

From the server point of view

 

You have to configure a DyeInjectionMonitor.

To do so, activate the instrumentation by creating a module, and activating the instrumentation like shown below :

 

 

You may configure the DyeInjectionMonitor by adding some "Dye Flag".

 

 

 

For instance, here I added the dye flag "ADDR1". Make sure the flag you've chosen appears in the authorized constants.

 

Deploy your application to the server.

 

You may encounter the following error while deploying from Workshop.

 

 

It comes from the fact the console in development mode does not use (in theory) the configuration management,

aka the "Lock & Edit" feature.

To fix that, use WLST to release the lock, like :

 

 

I know it's not cool, but sometimes that's just the way it is.

And if you're not familiar with WLST, it will be the perfect occasion :)

Once deployed, launch the class Component1.

 

Displaying the data with the WLDF console extension

 

Installing the console extension

 

The console extension has to be installed into your domain. A console extension is a single JAR file.

For the WLDF extension, it's shipped within the standard WLS distribution.

You will find it here : BEA_HOME \ wlserver_10.3 \ server \ lib \ console-ext \ diagnostics-console-extension.jar

Then copy it in the directory : DOMAIN_HOME \ console-ext

Restart your server and you should see a new tab :

 

 

Viewing the collected data

 

Click this new tab, and then go in the "Request" tab.

Choose the server on which you have the EAR deployed (if many)

If no data is visible, click reload and then refresh.

You should get something like :

 

 

If you chose a particular method call, you may see a more detailed view like :

 

 

Let's zoom the contextual window :

 

 

There you go : you have a powerful tool, right here with no extra product ! :)

Hope it gave you a good example of the AOP use of WLDF.

If you want more info about WLDF, take a look at the page :

http://download-llnw.oracle.com/docs/cd/E13222_01/wls/docs90/wldf_configuring/index.html

 

Have fun !

 

 

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