WofBPEL: A Tool for Automated Analysis of BPEL Processes

The Business Process Execution Language for Web Service, known as BPEL4WS, more recently as WS-BPEL (or BPEL for short) [1], is a process definition language geared towards Service-Oriented Computing (SOC) and layered on top of the Web services technology stack. In BPEL, the logic of the interactions between a given service and its environment is described as a composition of communication actions. These communication actions are interrelated by control-flow dependencies expressed through constructs close to those found in workflow definition languages. In particular, BPEL incorporates two sophisticated branching and synchronisation constructs, namely “control links” and “join conditions”, which can be found in a class of workflow models known as synchronising workflows formalised in terms of Petri nets in [3]. In the field of workflow, it has been shown that Petri nets provide a suitable foundation for performing static verification. Workflow verification engines such as Woflan [7] are able to analyse Petri net-based workflow models for various purposes such as soundness verification. Therefore, by translating BPEL processes to Petri nets and applying existing Petri net analysis techniques, we can perform static analysis on BPEL processes. To provide tool support for the analysis of BPEL processes, we developed WofBPEL, and a companion tool BPEL2PNML. BPEL2PNML translates BPEL process definitions into Petri nets represented in the Petri Nets Markup Language (PNML). WofBPEL, which is built using Woflan, performs static analysis on the output produced by BPEL2PNML. Currently it supports three types of analysis: detection of unreachable actions, detection of conflicting message-consuming activities, and metadata generation for garbage collection of unconsumable messages, as detailed in Sect. 2.2. As part of the design of BPEL2PNML, we formally defined a mapping from BPEL to Petri nets. This mapping is described in [5] and compared with other