MobilityReadingGroup

We give a summary of our recent research developments on multiparty session types for verifying distributed, parallel and concurrent programs, and our collaborations with industry partners. We shall first outline the multiparty session types and then explain how we started collaborations with industry to develop a protocol description language called Scribble. We then talk about the recent developments in Scribble, the runtime session monitoring framework used in Ocean Observatories Initiative and network protocol verifications. We also demonstrate how our multiparty session synthesis theory is applied to Zero Deviation Life Cycle project with Cognizant; and static deadlock analysis for Google’s Go language.

I shall talk about a difficulty to extend session types to be compositional in several contexts: multiparty session types, communicating automata and Linear Logic. I also talk about several solutions – some of them are motivated by practical applications of the session types.

Graphical choreographies, or global graphs, are general multiparty session specifications featuring expressive constructs such as forking, merging, and joining for representing application-level protocols. Global graphs can be directly translated into modelling notations such as BPMN and UML. In the first part of the talk, I will first present an algorithm whereby a global graph can be constructed from asynchronous interactions represented by communicating finite-state machines (CFSMs); and a sound characterisation of a subset of safe CFSMs from which global graphs can be constructed. In the second part, I will outline a few recent applications of this work to communicating timed automata and the Go programming language.

BETTY final project meeting keynote

Nobuko Yoshida’s talk will present a summary of recent papers on multiparty session types for verifying distributed, parallel and concurrent programs, illustrating how theoretical work is grounded on collaborations with industry partners. This research led to the development of the protocol description language Scribble and other work such as static deadlock analysis in Go.

Graphical choreographies, or global graphs, are general multiparty session specifications featuring expressive constructs such as forking, merging, and joining for representing application-level protocols. Global graphs can be directly translated into modelling notations such as BPMN and UML. In the first part of the talk, I will first present an algorithm whereby a global graph can be constructed from asynchronous interactions represented by communicating finite-state machines (CFSMs); and a sound characterisation of a subset of safe CFSMs from which global graphs can be constructed. In the second part, I will outline a few recent applications of this work to communicating timed automata and the Go programming language.

Go’s concurrency features differ from mainstream programming languages in that they are based on the high-level and formal model of CSP (or process calculi) by Tony Hoare in 1978. Over the years, a large body of research work was developed for understanding concurrency based on process calculi, but rarely applied directly in programming languages. I will talk about a static analyser we developed for detecting deadlocks in Go, inspired by a research area which gives “types” to process calculi. In a nutshell, the tool infers “types” for communication between goroutines from Go source code, then construct a bird’s eye view of all communication (also called choreography or global graph) possible at runtime, through which deadlocks and communication problems are discovered.

This talk will focus on the work-in-progress aspects of the tool. No knowledge of CSP/process calculi are needed but some understanding of concurrency in Go and static analysis concepts are expected.

Multiparty session types are a type system that can ensure the safety and liveness of distributed peers via the global specification of their interactions. To construct a global specification from a set of distributed uncontrolled behaviours, this talk explores the problem of fully characterising multiparty session types in terms of communicating automata. We equip global and local session types with labelled transition systems (LTSs) that faithfully represent asynchronous communications through unbounded buffered channels. Using the equivalence between the two LTSs, we identify a class of communicating automata that exactly correspond to the projected local types. We exhibit an algorithm to synthesise a global type from a collection of communicating automata. The key property of our findings is the notion of multiparty compatibility which non-trivially extends the duality condition for binary session types.

At the end of the talk, I also show a couple of applications of the synthesis theory of multiparty session types.

Multiparty session types are a type system that can ensure the safety and liveness of distributed peers via the global specification of their interactions. To construct a global specification from a set of distributed uncontrolled behaviours, this talk explores the problem of fully characterising multiparty session types in terms of communicating automata. We equip global and local session types with labelled transition systems (LTSs) that faithfully represent asynchronous communications through unbounded buffered channels. Using the equivalence between the two LTSs, we identify a class of communicating automata that exactly correspond to the projected local types. We exhibit an algorithm to synthesise a global type from a collection of communicating automata. The key property of our findings is the notion of multiparty compatibility which non-trivially extends the duality condition for binary session types.

At the end of the talk, I also show a couple of applications of the synthesis theory of multiparty session types.

We give a summary of our recent research developments on multiparty session types for verifying distributed, parallel and concurrent programs, and our collaborations with industry partners. We shall first outline the multiparty session types and then explain how we started collaborations with industry to develop a protocol description language called Scribble. We then talk about the recent developments in Scribble, the runtime session monitoring framework used in Ocean Observatories Initiative and network protocol verifications. We also demonstrate how our multiparty session synthesis theory is applied to Zero Deviation Life Cycle project with Cognizant; and static deadlock analysis for Google’s Go language.

We give a summary of our recent research developments on multiparty session types for verifying distributed, parallel and concurrent programs, and our collaborations with industry partners. We shall first introduce the multiparty session types and then explain how we started collaborations with industry to develop a protocol description language called Scribble. We then talk about the recent developments in Scribble, the runtime session monitoring framework used in Ocean Observatories Initiative and network protocol verifications. We also demonstrate how our multiparty session synthesis theory is applied to Zero Deviation Life Cycle project in Cognizant; and static deadlock analysis for Google’s Go language.

We give a summary of our recent research developments on multiparty session types for verifying distributed, parallel and concurrent programs, and our collaborations with industry partners. We shall first introduce the multiparty session types and then explain how we started collaborations with industry to develop a protocol description language called Scribble. We then talk about the recent developments in Scribble, the runtime session monitoring framework used in Ocean Observatories Initiative and network protocol verifications. We also demonstrate how our multiparty session synthesis theory is applied to Zero Deviation Life Cycle project in Cognizant; and static deadlock analysis for Google’s Go language.

We give a summary of our recent research developments on multiparty session types for verifying distributed and concurrent programs, including our collaborations with industry partners and NSF-funded project (Ocean Observatories Initiatives). The OOI provides an ultra large-scale cyberinfrustracture (OOI CI) for 25-30 years of sustained ocean measurements to study climate variability, ocean circulation and ecosystem dynamics. We shall first talk how Robin Milner, Kohei Honda and Yoshida started collaborations with industry to develop a web service protocol description language called Scribble and discovered the theory of multiparty session types through the collaborations with Red Hat. We then talk about applications of Scribble to the runtime session monitoring framework used in the OOI and Scala verification. We also summarise more recent results and applications using Multiparty Session Types.

Actor coordination armoured with a suitable protocol description language has been a pressing problem in the actors community. We study the applicability of multiparty session type protocols for verification of actor programs. We incorporate sessions to actors by introducing minimum additions to the model such as the notion of actor roles and protocol mailboxes. The framework uses Scribble, which is a protocol description language based on multiparty session types. Our programming model supports actor-like syntax and runtime verification mechanism guaranteeing communication safety of the participating entities. The usage of multiple roles allows safe cooperative interconcurrency in a single actor. We present the design of our session actor library in Python, which is evaluate by implementing twelve use cases from an actor benchmark suit. Benchmarks demonstrate that the runtime checks induce negligible overhead. We also present a recent work incorporating the session actors model into Erlang, where session types are used for faster error recovery on top of Erlang supervision trees.

We give a summary of our recent research developments on multiparty session types for verifying distributed, parallel and concurrent programs, and our collaborations with industry partners. We shall first talk how the session types were discovered from the theory of the pi-calculus, and how we started collaborations with industry to develop a protocol description language called Scribble. We then talk about the recent developments in Scribble, the runtime session monitoring framework used in Ocean Observatories Initiative and network protocol verifications with demos. We also talk how our synthesis theory is applied to Zero Deviation Life Cycle project with Cognizant. Finally we show how multiparty session types are used to generate safe MPI code.

We give a summary of our recent research developments on multiparty session types for verifying distributed and concurrent programs, and our collaborations with industry partners and a major, long-term, NSF-funded project (Ocean Observatories Initiatives) to provide an ultra large-scale cyberinfrustracture (OOI CI) for 25-30 years of sustained ocean measurements to study climate variability, ocean circulation and ecosystem dynamics. We shall first talk how Robin Milner, Kohei Honda and Yoshida started collaborations with industry to develop a web service protocol description language called Scribble and discovered the theory of multiparty session types through the collaborations. We then talk about the recent developments in Scribble and the runtime session monitoring framework used in the OOI CI. Finally we summarise our recent other results on Multiparty Session Types.

Graphical choreographies, or global graphs, are general multiparty session specifications featuring expressive constructs such as forking, merging, and joining for representing application-level protocols. Global graphs can be directly translated into modelling notations such as BPMN and UML . In this talk, I will present (i) an algorithm whereby a global graph can be constructed from asynchronous interactions represented by communicating finite-state machines (CFSMs); and (ii) a sound and complete characterisation of a subset of safe CFS Ms from which global graphs can be constructed.