Higher-order Behavioral Contracts for Distributed Components

Abstract

Inspired by the Design by Contract paradigm, we introduce CONSUL, a contract system for distributed components. CONSUL monitors distributed components at run time with higher-order behavioral contracts. Contract monitoring is local to a component, and the component is treated as a black box. Thus it does not disturb the highly decoupled nature of distributed components and allows heterogeneous implementation languages and platforms without modifications to a component’s code. We describe the design, semantics and properties of CONSUL (adapter transparency and correct blame), and show that its contracts can capture and enforce precise and useful properties of a variety of off-the-shelf components.