Multiparty Session Actors

Actor coordination armoured with a suitable protocol description language hasbeen a pressing problem in the actors community. We study the applicability ofmultiparty session type (MPST) protocols for verification of actor programs. Weincorporate sessions to actors by introducing minimum additions to the modelsuch as the notion of actor roles and protocol mailboxes. The framework usesScribble, which is a protocol description language based on multiparty sessiontypes. Our programming model supports actor-like syntax and runtimeverification mechanism guaranteeing communication safety of the participatingentities. An actor can implement multiple roles in a similar way as an objectcan implement multiple interfaces. Multiple roles allow for cooperativeinter-concurrency in a single actor. We demonstrate our framework by designingand implementing a session actor library in Python and its runtime verificationmechanism. Benchmark results demonstrate that the runtime checks inducenegligible overhead. We evaluate the applicability of our verificationframework to specify actor interactions by implementing twelve examples from anactor benchmark suit