A Practical Tool-Chain for the Development of Coordination Scenarios Graphical Modeler, DSL, Code Generators and Automaton-Based Simulator

摘要

Coordination scenarios have high demands on concurrency and interaction. However, these are typical sources for flaws in both design and implementation. A modeling approach enables reasoning about distributed algorithms and finding deficiencies right from the beginning. The Peer Model has been introduced as a modeling tool for distribution, concurrency and blackboard-based collaboration and coordination, relying on known foundations like tuple spaces, Petri Nets and Actor Model. A runtime system exists that serves Java developers for prototyping, but still a feasible tool-chain was missing, like for most academic systems. This paper presents a practical new tool-chain for the Peer Model consisting of a graphical modelling tool, building on a drawing program that exports XML. A translator parses the XML and translates it into a newly developed domain specific language that is the basis for code generation. One target is a new, formal automaton-based runtime written in the Go programming language. It allows systematic simulation runs of user models. The demo shows a peer competition scenario, where several players play a game, a global state holds the players' scores, and in addition each peer maintains a decentralized state. Before taking a move in the game, a peer asserts its current local state to be the same like the global one. If this is the case, it carries out its action and distributes the information about it to all other players for further verification. The scenario captures core coordination mechanisms found in blockchain systems.