If you're looking to roll your own, you might want to look into the work done with X-Trace.
Also, my M.Sc. thesis is focusing on doing distributed event tracing for web applications. I'm not sure if I'll end up open-sourcing it or not, but some of the work has been published http://dl.acm.org/citation.cfm?id=1958783
Also, my M.Sc. thesis is focusing on doing distributed event tracing for web applications. I'm not sure if I'll end up open-sourcing it or not, but some of the work has been published http://dl.acm.org/citation.cfm?id=1958783