Log Lenya with Chainsaw v2

Chainsaw is a powerful GUI-based Log viewer. It's a companion application to Log4j and seems to have replaced LogFactor5. Pros are:

mature application, opensource, clean GUI, easy to install (web start)
allows you to easily view the logs of a specific component of your webapp

See also CocoonLog4J and Chainsaw homepage

Getting Chainsaw v2

Web start

you can launch Chainsaw with Web Start here
at the startup popup, select "SocketReceiver" on "Port 4445"

Installing Chainsaw locally

(not tested yet)

Configuring Lenya (using SocketAppender)

Set this properties in WEB-INF/web.xml (it's already in there a couple of times, just make sure that it's at least uncommented in one place) :

<init-param>
  <param-name>logger-class</param-name>
<param-value>org.apache.avalon.excalibur.logger.Log4JLoggerManager</param-value>
</init-param>

<init-param>
  <param-name>log4j-config</param-name>
  <param-value>/WEB-INF/log4j.xconf</param-value>
</init-param>

In WEB-INF/log4j.xconf, comment out what's there and add:

<appender name="COCOON_DEFAULT"
class="org.apache.log4j.net.SocketAppender">
   <param name="RemoteHost" value="localhost" />
   <param name="Port" value="4445" />
</appender>

<root>
  <priority value ="debug" />
  <appender-ref ref="COCOON_DEFAULT" />
</root>

Using Chainsaw

at the bottom of the window, a tab called "localhost.localdomain" should appear. click on it.
on the left side, you can select for which component of lenya you want to see the logs (right-click).
when you want an overview of your webapp, focus on the "Root Logger" and refine the focus on "info" (debug is way too verbose)
when you analyse a specific component, focus on your component and refine the focus on "debug"

Other Ressources: