Event Actors Based Approach for

Supporting Analysis and Verification of

Event-Driven Architectures

Huy Tran and Uwe ZdunSoftware Architecture Group

Faculty of Computer Science

University of Vienna, Austria.

http://cs.univie.ac.at/swa

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About UsSoftware Architecture Group @ University of Vienna, Austria

Founded in 2010

1 University Professor

1 Post-doctoral Researcher

7 Pre-doc Research Assistants

Research areas

software architecture, distributed systems, event-driven

architecture, model-driven software development, service-

oriented computing

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Content

Problem Verification supports for event-driven software

systems

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Proposed Solution Event actors, event-based interfaces, Petri Nets

SummaryAchievements, lessons learned, future directions

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ProblemContext: Event-driven architectures

Event Publishers Event Consumers

Event

Channel/Bus

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ProblemContext: Event-driven architectures

SmartFlow Project

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ProblemContext: Event-driven architectures

EBBITS Project

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ProblemSummary

Event-driven architectures

+ Loose coupling

+ Independent execution

+ Potential for flexibility, scalability and concurrency

- Inherently non-deterministic

- Challenging for understanding and analyzing (esp. large architecture designs)

- Limited supports for verifications (mostly low-level abstractions, i.e., pub/sub)

A

B

event

event

event

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Proposed Solution

Reducing non-determinism while preserving loose coupling, flexibility Well-defined event-based interfaces

Easy-to-understand abstractions Close to traditional constructs: sequence, branching, etc.

Textual vs. graphical

Supports for analysis by grounding on formal specifications Process algebras, Petri Nets, etc.

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Proposed SolutionReducing non-determinism

event(s) event(s)

Event-based interface

input output

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Proposed SolutionEasy-to-understand abstractions

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Proposed SolutionGrounding on formal specifications

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Dynamic Event-Driven Actors (DERA)Overview

Developerdevelops

Snapshot

analyzes &verifies

Execution Domain

Execution Domain

Execution Domain

eventbridge

DERA Engine

deploys

Petri nets description (e.g., PNML)

DeraLang

captures

translates

translates

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Dynamic Event-Driven Actors (DERA)Meta-model of DERA primitives

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Dynamic Event-Driven Actors (DERA)DERA Primitives: Computational Unit

Event Actor

• computational unit or data

processingeTruck

Arrived

eFreeDock

Requested

TruckMonitor

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Dynamic Event-Driven Actors (DERA)DERA Primitives: Branching Unit

Condition

• branching unit (i.e.,

if-then-else)

eStoring

Finished

isStoring

Finished

eUnit

Stored

eStoring

NotFinished

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Dynamic Event-Driven Actors (DERA)DERA Primitives: Synchronization Unit

Barrier

• synchronization uniteTruck

MovedeUnloading

Started

SynchronizereCamera

Received

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Dynamic Event-Driven Actors (DERA)DERA Primitives: Domain Bridging Unit

Event Bridge

• connect two domains

Yard Management DomainWarehouse Management Domain

YMS-to-WMS

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Grounding DERA constructs on Petri Nets

General Petri Nets representation of DERA constructs

General Petri Nets representation of a “connection”

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Grounding DERA constructs on Petri Nets

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Dynamic Event-Driven Actors (DERA)An example of mapping a DERA-based system to Petri Nets

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DERA-based system verificationsDead execution paths

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DERA-based system verificationsDeadlocks (jamming before reaching the end)

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DERA-based system verificationsLivelocks (trapping in endless cycles)

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SummaryAchievements, lessons learned, and future directions

Reducing non-determinism is important to enhance supports for understanding and analyzing event-based systems

Intuitive notational abstractions, which are close to traditional constructs: important for lessening

the learning-curve

grounded on formal specifications: enabling formal verifications

Potential future directions additional constructs

other aspects: data, fault handling, temporal, etc.

inter-domain specifications and verifications

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Many thanks for your attention!

Huy Tran

huy.tran@univie.ac.at

Research Group Software Architecture

Faculty of Computer Science

University of Vienna, Austria.

http://cs.univie.ac.at/swa