An Erlang Implementation of Multiparty Session Actors

TL;DR

This paper presents an Erlang framework that enforces communication protocols in actor-based systems using multiparty session types, improving reliability and fault detection in distributed applications.

Contribution

It adapts multiparty session types to Erlang's actor model, enabling protocol monitoring and violation detection in real-world applications.

Findings

Successfully implemented protocol monitoring in Erlang applications.

Detected communication violations and managed session termination.

Validated approach with DNS and chat server case studies.

Abstract

By requiring co-ordination to take place using explicit message passing instead of relying on shared memory, actor-based programming languages have been shown to be effective tools for building reliable and fault-tolerant distributed systems. Although naturally communication-centric, communication patterns in actor-based applications remain informally specified, meaning that errors in communication are detected late, if at all. Multiparty session types are a formalism to describe, at a global level, the interactions between multiple communicating entities. This article describes the implementation of a prototype framework for monitoring Erlang/OTP gen_server applications against multiparty session types, showing how previous work on multiparty session actors can be adapted to a purely actor-based language, and how monitor violations and termination of session participants can be reported in line with the Erlang mantra of "let it fail". Finally, the framework is used to implement two case studies: an adaptation of a freely-available DNS server, and a chat server.