An extensible architecture for run-time monitoring of conversational web services

Trust in Web services will be greatly enhanced if these are subject to run-time verification, even if they were previously tested, since their context of execution is subject to contin-uous change; and services may also be upgraded without notifying their consumers in advance. Conversational Web services introduce added complexity when it comes to run-time verification, since they follow a conversation protocol and they have a state bound to the session of each consumer accessing them. Furthermore, conversational Web services have different policies on how they maintain their state. Ac-cess to states can be private or shared; and states may be transient or persistent. These differences must be taken into account when building a scalable architecture for run-time verification through monitoring. This paper, building on a previously proposed theoretical framework for run-time ver-ification of conversational Web services, presents the design, implementation and validation of a novel run-time monitor-ing architecture for conversational services, which aims to provide a holistic monitoring framework enabling the inte-gration of different verification tools. The architecture is validated by running a sequence of test scenarios, based on a realistic example. The experimental results revealed that the monitoring activities have a tolerable overhead on the operation of a Web service