A Service-Oriented Architecture (SOA) Framework for Choreography Verification

Service composition is fundamental in the SOA paradigm. It is oriented to build complex applications from smaller components. The design of composing service-based applications is mainly carried out throughout two composition techniques namely choreography and orchestration. Although these two composition models are different in nature, they are complementary. Choreography presents an abstract description of protocols. It offers a top view of the management rules which govern the interactions between the services involved in a decentralized application. On the other hand, orchestration provides details of the executable process at single peers which are necessary for the implementation of choreography. In this context, one open research problem, is the correct transformation of choreography specifications to orchestration specifications since orchestration provides more details to choreography specification. The choreography transformation has been the subject of several research works. Nevertheless, the existing works have considered that the choreography, on which their transformations are based, is correct by default. So, they have not sought to verify whether it is free of any error or not. Actually, due to the message passing nature of web services interaction, many subtle errors can occur. So, it is crucial to implement a checking process oriented to identify eventual incompatibilities that may arise. For this purpose, we present a formal verification approach based on the SPIN model-checker. The approach automatically transforms WS-CDL choreography specifications to Promela code for verification purposes. We verify non-functional properties that are expressed with linear temporal logic.