Haley: An End-to-End, Scalable Web Service

Composition Tool

Haibo Zhao, Prashant DoshiLSDIS Lab., The University of Georgia

17th International World Wide Web Conference (WWW08)Developers Track, April 23, 2008

Outline

• Introduction and Motivation (Why Haley?)

• Haley Features in Brief (What does Haley do?)

• Haley Architecture and Modules (How it works?)

• Scenario and Demo (How it can be used?)

• Discussions and Future work (How good/bad it is?)

Introduction: Web service composition

Individual Web services Value-added Web service composition into BPEL processes

Motivation

• Existing approaches– Manual approach (BPEL coding by hand)

• Very tedious and error-prone• Quickly becomes unmanageable

– Automated approaches (Astro, Synthy)• Scalability

– Major limitation of existing automated approaches due to the inherent complexity of planning algorithms

• Quality of the composition– Optimize QoS parameters

» Minimize invocation cost, response time, …» Maximize reliability, ...

What does Haley do?Haley aims to provide an end-to-end, scalable and automatedtool suite to compose Web services into BPEL processes*

• Automation– Haley takes functional descriptions (WSDL/SAWSDL) and non-

functional descriptions (WS-agreement) of component Web services to automatically compose BPEL processes

• Scalability– Haley utilizes a hierarchy modeler to model the hierarchy usually

found in business processes

• Easy-to-use– Intuitive UI (EMF, GMF) that hides the complexity of AI planning– Avoid tedious and error-prone BPEL coding

*Haley: A Hierarchical Framework for Logical Composition of Web Services, Haibo Zhao, Prashant Doshi, IEEE International Conference on Web Services, Research Track, ICWS07, Salt Lake City, Utah

Features of Haley• Use Web services described in WSDL and SAWSDL

• Browse functionality of Web service with SAWSDL Viewer

• Model process hierarchy

• Specify initial state and business goals of processes

• AI-planning based flow generation using Prolog

• Programmatically generate BPEL code using ActiveBpel API

• Graphically view BPEL code in Eclipse

Haley Architecture

Demonstration Scenario

Translation servicewebserviceX.net

ISBN lookupAmazon Associates

Web Service

Amazon Associates Web

ServiceCurrency servicewebserviceX.net

Address Standardization

Service

Rate Calculation Service

ZIP lookup service

Currency servicewebserviceX.net

Demo

• Importing candidate Web services

• specifying hierarchy

• specifying desired properties of the composition

• generating planning problem file

• generating plan

• generating BPEL file

DEMO

Discussion and Future Work• Significance of Haley

– An easy-to-use, end-to-end and practical tool– An automated WS composition tool hiding the

complexity of AI planning and BPEL from designers– Scalable

• Limitations– Current version focuses on control flow– No execution engine embedded

• Future work– Consider data mediation– Integrate service discovery– Continue to improve the usability and reliability

Thank you!

Questions?

Haibo Zhaozhao@cs.uga.edu

http://denali.cs.uga.com/projects