A Formal Semantics for the WS-BPEL Recovery Framework: The pi-Calculus Way

Abstract

While current studies on Web services composition are mostly focused - from the technical viewpoint - on standards and protocols, this work investigates the adoption of formal methods for dependable composition. The Web Services Business Process Execution Language (WS-BPEL) - an OASIS standard widely adopted both in academic and industrial environments - is considered as a touchstone for concrete composition languages and an analysis of its ambiguous Recovery Framework specification is offered. In order to show the use of formal methods, a precise and unambiguous description of its (simplified) mechanisms is provided by means of a conservative extension of the pi-calculus. This has to be intended as a well known case study providing methodological arguments for the adoption of formal methods in software specification. The aspect of verification is not the main topic of the paper but some hints are given.