A correct-by-construction model for asynchronously communicating systems

The design and verification of distributed software systems is often hindered by their ever-increasing complexity and their asynchronous operational semantics. This article considers choreography specifications for distributed systems to reduce that complexity. We use labelled state-transitions systems as ground model for both choreographies and the corresponding distributed systems. Based on Event-B method, we propose a stepwise correct-by-construction model to build asynchronous distributed systems which a priori realise their choreographies. We rely on a sufficient and necessary realisability condition and we apply several refinement steps w.r.t. that condition to generate the distributed peers. The first refinement returns peer behaviours obtained by synchronous projection. The previously computed system is then refined into its asynchronous version using unbounded FIFO buffers. We prove, thanks to invariant preservation, that a sequence of exchanged messages is preserved at each refinement step. We provide a formalised proof of a realisability algorithm for deterministic choreographies. Besides that, our contribution is twofold: the approach is a priori and the problackposed solution scales up to any number of peers communicating with each other

Facilitating the Implementation of Distributed Systems with Heterogeneous Interactions

International audienceWe introduce HDBIP an extension of the Behavior Interaction Priority (BIP) framework. BIP is a component-based framework with a rigorous operational semantics and high-level and expressive interaction model. HDBIP extends BIP interaction model by allowing heterogeneous interactions targeting distributed systems. HDBIP allows both multiparty and direct send/receive interactions that can be directly mapped to an underlying communication library. Then, we present a correct and efficient code generation from HDBIP to C++ implementation using Message Passing Interface (MPI). We present a non-trivial case study showing the effectiveness of HDBIP