Towards cost-aware service recovery

We present a semi-automated approach and framework for cost-aware recovery from service inconsistency arising due to unreliable service actions. A range of costs such as time are parameterised and modelled generically using cost algebras. With respect to a user-provided business specification, we distinguish end-state consistency, which must be achieved at service completion, from strong consistency, which may be momentarily violated. Our approach ensures optimal end-state consistency for services where action failure may lead to temporary violations of strong consistency or end-state consistency. Enterprises could not otherwise optimally and dynamically handle strong consistency violation, especially with respect to a variety of costs. Our approach provides quantitative analysis by defining a service model as an high-level message sequence chart (hMSC), annotating service actions with costs, then interpreting the model as a weighted (Mazurkiewicz) trace language, catering for costs in the presence of true concurrency. We devise a framework and method which checks such a model and ensures service end-state consistency optimally by concatenating the traces of recovery strategies (expressed by MSCs) from an enterprise service repository. We evaluate our approach using a popular online shop case study.