I've just uploaded to JIRA the first proper version of a tool I've
been working on for viewing and filtering zookeeper logs. Source is
available at: https://issues.apache.org/jira/browse/ZOOKEEPER-773.
Just patch over a current zookeeper source tree and cd to src/contrib/
zkgraph. ant jar to compile, and then bin/zkgraph.sh to run.
It's quite rough around the edges at the moment. There's a log view, a
server view, a session view and statistics view. The readme file has
information on applying filters.
Any suggestions on how to flesh it out are very welcome :)