When developing and/or debugging BPEL processes, the Oracle BPEL Console is your best friend. Every change to every variable, every activity that was executed, everything is right there for you to inspect, whether the instance is still in-flight or already completed. But although this sounds like the ultimate debugging tool, I’m sure you’ve noticed like me that when your processes get really big (which they tend to do rather quickly), there’s two reasons why debugging can be difficult. The first is plain and simple “information overload”. If your audit flow contains hundreds of activities and possibly thousands of variable data changes, finding an individual piece of information is not trivial. I find the second reason, however, to be of even more profound impact: the BPEL console will not show you the execution path through your process flow (which would indicate which parts of the code got executed, and which didn’t), but rather it displays a long, sequential list of  Activities that were executed. Especially if you have a lot of switch and/or pick statements, and if your code contains loops (in which case each iteration will add all executed Activities to the list), determining “what happened” during execution of your instance from this long, long audit trail might prove a challenge.

In a “mini-series” of Blog entries, I will share a number of techniques that I have used in situations like this, to extract logging/debug information from a BPEL process instance using BPEL Sensors. This first entry will focus on a simple, straightforward form of logging, using a “Variable Sensor” to provide a sort of “management summary” of the execution of a BPEL process instance. .... Read the rest of this entry »