Flexible and expressive aspect-based control over service compositions in the Cloud

Accountability properties (e.g., security and privacy proper- ties for trustworthy data stewardship) are becoming increas- ingly important for Cloud applications. Frequently, they have to be enforced on large-scale service-based legacy ap- plications. In this paper we argue that real-world service in- frastructures are best modeled in terms of three abstraction levels and that (partially invasive) adaptations involving all levels are needed to handle the corresponding evolution sce- narios. In this paper, we motivate these issues for the case of Apache CXF, a popular service infrastructure, and secure logging as a basic accountability property. We propose an initial version of a DSL for flexible and expressive control over the execution of service compositions on three levels: service, interceptor and implementation. We also present a corresponding prototype tool and infrastructure we have implemented over CXF. Finally, we show how our method can be applied to enable secure logging.