Incremental correct-by-construction of distributed systems

Abstract

Abstract Although today’s software systems are distributed by necessity, their design verification and validation is still an open issue due to their ever-increasing complexity. This paper proposes a stepwise development method allowing a designer to build correct-by-construction distributed systems. System correctness is handled w.r.t.a realizability property. We assume a top-down approach where systems are specified with a global behavioral model referred to as conversation protocol (CP). This specification defines all allowed sequences of messages exchanged between distributed peers implied in that conversation. Given a CP, realizability is defined whether there exists a set of peers such that their interaction with each other leads to the same sequences as specified by the original CP. Our proposal ensures that the built CP is realizable-by-construction. We define a set of sufficient conditions preserving realizability at CP level. We then propose an algebra of operators for incremental CP building w.r.t.to the defined conditions. We also prove that our proposal is correct and we show how this is supported with mechanized proofs. Lastly, we implemented our approach using Rodin platform and validated it on several case studies.