Reo + mCRL2 : A framework for model-checking dataflow in service compositions

Abstract

Abstract. The paradigm of service-oriented computing revolutionized the field of software engineering. According to this paradigm, new systems are composed of existing stand-alone services to support complex cross-organizational business processes. Correct communication of these services is not possible without a proper coordination mechanism. The Reo coordination language is a channel-based modeling language that introduces various types of channels and their composition rules. By composing Reo channels, one can specify Reo connectors that realize arbitrary complex behavioral protocols. Several formalisms have been introduced to give semantics to Reo. In their most basic form, they reflect service synchronization and dataflow constraints imposed by connectors. To ensure that the composed system behaves as intended, we need a wide range of automated verification tools to assist service composition designers. In this paper, we present our framework for the verification of Reo using the mCRL2 toolset. We unify our previous work on mapping various semantic models for Reo, namely, constraint automata, timed constraint automata, coloring semantics and the newly developed action constraint automata, to the process algebraic specification language of mCRL2, address the correctness of this mapping, discuss tool support, and present a detailed example that illustrates the use of Reo empowered with mCRL2 for the analysis of dataflow in service-based process models.

Combine and conquer: Relating BIP and Reo

“…Controlling and constraining multiparty synchronization is, however, more complex in ACP than it is in BIP and Reo (because additional operators, communication and block, need to be used beside parallel composition to specify admissible synchronizations). This is illustrated in work by Krause et al [30], who encoded Reo's semantics (i.e., Reo's composition operator and a number of primitives) in mCRL2 [31], a modern process specification language based on ACP.…”

Partially distributed coordination with Reo and constraint automata

“…This separation facilitates verbatim reuse, independent modification, and compositional construction of protocol implementations (i.e., Reo connectors) in a straightforward way. Moreover, Reo has a formal foundation, which enables formal analysis of connectors (e.g., model checking [41]). This makes statically verifying that a given protocol does not dead- Reo has been successfully used as a language for expressing orchestration protocols for composition of Web services [37,38].…”

“…It has a formal graphical syntax (analogous to electronic circuit diagrams), and a few formal semantics based, for instance, on compositional ca [4]. The formal basis of Reo guarantees possibilities for both model checking and verification [41].…”

A Procedure for Splitting Processes and its Application to Coordination

“…Below, we give the processes of the connectors in Figures 1a and 1c. See [16,13,14,15] for more examples. …”

“…However, while intuitively valid, a formal argument establishing the soundness of this optimization does not exist yet. In this paper, we present such a proof, based on the process algebraic semantics of Reo [16,13,14,15]. In this semantics, one associates every connector with a process term describing its behavior.…”