Enhancing WS-BPEL Dynamic Invariant Generation Using XML Schema and XPath Information

摘要

The dynamic and asynchronous nature of OASIS WS-BPEL 2.0 standard language for web service composition presents a challenge for traditional white-box testing techniques. Takuan is a tool that can help with this problem. It analyzes execution logs of a WS-BPEL process in a real-world WS-BPEL engine to dynamically generate composition invariants. Nevertheless, it suffered some performance issues when handling a large number of variables with complex multidimensional content. We present two techniques implemented to automatically alleviate these issues: dynamic analysis of XPath expressions to avoid inferring nonsensical invariants, and discarding invariants enforced by the XML Schema. We present practical results supporting our work and comment the impact and applicability of these techniques beyond WS-BPEL itself.