Compositional Design, Implementation, and Verification of Swarms (Technical Report)
For developers of peer-to-peer systems, this work provides a compositional framework that facilitates modular design and verification, but it is an incremental extension of existing swarm protocol theory.
The paper addresses the lack of compositionality in swarm protocols, which hinders modular development and code reuse. It introduces novel theory and techniques for compositional specification, verification, and implementation, enabling correct reuse of pre-existing components.
Swarm protocols are a recently introduced formalism for specifying, implementing, and verifying peer-to-peer systems called swarms. A swarm consists of distributed agents called machines that communicate by asynchronous event propagation. Following a local-first model, each machine can progress without requiring continuous connectivity to other machines. Existing models of swarms are not compositional, making the modular development of large and complex swarm applications as well as the reuse of code difficult. We address these issues by presenting novel theory and techniques for the compositional specification, verification, and implementation of swarms. These results enable the correct compositional reuse of pre-existing swarm protocols and machine implementations. We implement these contributions in a companion software artifact which enables the automatic integration of independently designed and verified swarm components.