Fault, compensation and termination in WS-BPEL 2.0 - A comparative analysis

Abstract

One of the most challenging aspects in Web Service composition is guaranteeing transactional integrity. This is usually achieved by providing mechanisms for fault, compensation and termination (FCT) handling. WS-BPEL 2.0, the de-facto standard language for Business Process Orchestration provides powerful scope-based FCT-handling mechanisms. However, the lack of a formal semantics makes it difficult to understand and implement these constructs, and renders rigid analysis impossible. The general concept of compensating long-running business transactions has been studied in different formal theories, such as cCSP and Sagas, but none of them is specific to WS-BPEL 2.0. Other approaches aim at providing formal semantics for FCT-handling in WSBPEL 2.0, but only concentrate on specific aspects. Therefore, they cannot be used for a comparative analysis of FCT-handling inWS-BPEL 2.0. In this paper we discuss the BPEL approach to FCT-handling in the light of recent research. We provide formal semantics for the WS-BPEL 2.0 FCT-handling mechanisms which aims at capturing the FCT-part of the WS-BPEL 2.0 specification in full detail. We then compare the WSBPEL 2.0 approach to FCT-handling to existing formal theories.