Towards Dynamic Evolution of Service Choreographies

To stay on the cutting edge, Web services ought to adapt themselves to the evolving business requirements and the changing environments. For a long-running service choreography, its member services may need to evolve even at run-time. However, inconsistencies or spurious results (e.g., unspecified receptions and deadlocks) may occur if these services evolve dynamically in an uncoordinated manner. To cope with this problem, we propose an approach that supports the dynamic evolution of choreographies. In our approach, two mechanisms are proposed to make sure that the choreography evolution can be conducted in an orderly fashion. First, an evolution protocol is proposed to support dynamic co-evolution of the member services in a choreography. Second, the proposed approach restricts choreography changes to one single service only if the relevant partner services can evolve simultaneously. A typical purchase order application is used to motivate our proposal and illustrate the viability of our approach.