On using bpel extensibility to implement ogsi and wsrf grid workflows
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On Using BPEL Extensibility to Implement OGSI and WSRF Grid Workflows. Aleksander Slomiski. Presented by Onyeka Ezenwoye CIS 6612 - Advanced Topics in Software Engineering. Outline. Agenda Background BPEL Overview BPEL/OGSI BPEL/WSRF Other Issues Conclusion. Agenda. Background.

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On Using BPEL Extensibility to Implement OGSI and WSRF Grid Workflows

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On using bpel extensibility to implement ogsi and wsrf grid workflows

On Using BPEL Extensibility to Implement OGSI and WSRF Grid Workflows

Aleksander Slomiski

Presented by

Onyeka Ezenwoye

CIS 6612 - Advanced Topics in Software Engineering


On using bpel extensibility to implement ogsi and wsrf grid workflows

Outline

Agenda

Background

BPEL Overview

BPEL/OGSI

BPEL/WSRF

Other Issues

Conclusion

Agenda

Background

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion


On using bpel extensibility to implement ogsi and wsrf grid workflows

Outline

Grid: A dynamicmulti-institutional network of computers that come together to share resources for the purpose of coordinatedproblem solving.

resource

Agenda

Background

application

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion

institutional boundary

  • Achieved through:

  • Open general-purpose protocols

  • Standard interfaces


On using bpel extensibility to implement ogsi and wsrf grid workflows

Outline

Web Services: A Web service is an application that is accessible over the internet.

Enterprise A

Enterprise C

App 1

App 1

App 1

App 1

App N

App N

App N

App N

.NET

etc.

CORBA

Java RMI

Internet

Firewall

Firewall

Firewall

Firewall

Enterprise B

Enterprise D

Agenda

Background

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion

  • Core Technologies:

    • XML (eXtensible Markup Language)

    • SOAP (Simple Object Access Protocol)

    • WSDL (Web Service Description Language)


On using bpel extensibility to implement ogsi and wsrf grid workflows

Outline

WSDL

<definition namespace = “http/… “>

<message>+ defines data elements of operations

<part>+ components of the message

</message>

<portType> defines the web service interface

<operation>+ operations that can be performed

<input>

<output>

<fault>*

</portType>

<binding> comms. protocols for operations </binding>

<service> a list of binding and ports to the bindings

</service>

</definition>

Service Broker

WSDL

Subscribe

Publish

Service Consumer

Service Provider

Bind

Client

Service

Reply

Legend

program boundary

request flow

module boundary

reply flow

Service Description

Agenda

Background

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion


On using bpel extensibility to implement ogsi and wsrf grid workflows

Outline

Open Grid Service Infrastructure (OGSI) - 2001

Grid service interface standard

Methods allow access to Grid service

As well as Grid service state (SDE)

Optional factory interface

Naming and referencing of Grid services

Extends WSDL 1.1 (GWSDL)

OGSI Registry

Grid Service Reference

(GSR)

Grid Service Handle (GSH)

Publish GSR

Service Consumer

Service Provider

Bind

Client

Grid Service

Reply

Legend

program boundary

request flow

module boundary

reply flow

Grid Service Reference

Agenda

Background

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion

  • OGSI Grid service locator:

    • Multiple GHSs + GSRs + interface description


On using bpel extensibility to implement ogsi and wsrf grid workflows

Outline

Web Service Resource Framework (WSRF) - 2004

Distinguish between service and stateful resource

Model stateful resource as a Web service

Modular (users decide which specification to use)

OGSI to WSRF*

Agenda

Background

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion

* www.globus.org/wsrf


On using bpel extensibility to implement ogsi and wsrf grid workflows

Outline

Workflow: A description of the sequence of interaction between a set of activities that are performed together to achieve a common goal.

Step 1

Step 3

Step 2

Step 4

Activity

Condition / interaction

Agenda

Background

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

  • Rapid composition

  • Automation

  • Management

Conclusion


On using bpel extensibility to implement ogsi and wsrf grid workflows

Outline

BPEL: An XML based workflow language for composing aggregate Web services.

result

phrase

Google Spell-checker WS

Amazon Store WS

Agenda

<portType name="GooglePortType">

<operation name="doSpellingSuggestion">

<input message="type:String"/>

<output message="type:String"/>

</operation>

</portType>

Background

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion

result

query

<portType name=“AmazonPortType">

<operation name="ItemSearch">

<input message="type:ComplexType"/>

<output message="type:Array"/>

</operation>

</portType>


On using bpel extensibility to implement ogsi and wsrf grid workflows

Outline

Google-Amazon BPEL process

BPEL Engine interprets XML-grammar

Exposed as a Web service

Described by WSDL (version 1.1)

phrase

Google Spell-checker WS

result

assignment activity

query

result

Amazon Store WS

Agenda

Background

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion

<portType name=“Google-AmazonPortType">

<operation name=“GoogleAmazonSearch">

<input message="type:String"/>

<output message="type:Array"/>

</operation>

</portType>


On using bpel extensibility to implement ogsi and wsrf grid workflows

Outline

Partners

<partnerLinks>

<partnerLink myRole="googleAmazon"

partnerLinkType="lns:googleAmazonLinkType"/>

<partnerLink partnerRole =“Google"

partnerLinkType="lns: GoogleLinkType "/>

<partnerLink name=“Amazon“

partnerLinkType="lns:AmazonLinkType"/>

</partnerLinks>

Google

Amazon

Partners

Agenda

receive

Background

BPEL

invoke

BPEL / OGSI

invoke

BPEL / WSRF

reply

Google-Amazon

Other Issues

Activities

<process>

<flow>

<receive name="receive" partnerLink=“googleAmazon" …>

</receive>

<invoke name="invokeGoogle" partnerLink =“google“ …>

</invoke>

<invoke name="invokeAmazon" partnerLink="amazon" …>

</invoke>

<reply name="reply" partnerLink=“googleAmazon" …>

</reply>

</flow>

</process>

Conclusion


On using bpel extensibility to implement ogsi and wsrf grid workflows

Outline

Google-Amazon BPEL process

Agenda

Background

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion

Screenshot from ActiveWebflowTM Professional


On using bpel extensibility to implement ogsi and wsrf grid workflows

Outline

Fault Handling

Two constructs for handling faults; <catch> and <catchAll>.

Event Handling

Timeout

n

5

3

1

process

5

1

BPEL Engine

Agenda

<message name=“requestMessage">

<part name="firstName" type="xsd:string"/>

<part name=“lastName" type="xsd:string"/>

<part name=“custID" type="xsd:int"/>

</message>

Background

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion

Message Correlation


Bpel and ogsi integration

Outline

BPEL And OGSI Integration*

  • Leveraging BPEL abstractions

    • BPEL Partner is known by interface (PortType)

    • Very powerful integration mechanism!

  • Understands natively GSH/Locator as service reference

    • Handle automatically GSH to GSR conversion

  • Supports Explicit and Implicit Lifecycle

    • GPEL workflow engine is also OGSI Factory

      * Aleksander Slomiski

Agenda

Background

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion


Issues in ogsi integration

Outline

Issues in OGSI Integration *

  • GSH/GSR and WS-Addressing

    • Endpoint Reference (EPR) is not GSH or GSR …

  • BPEL and OGSI Factory

    • BPEL Engine acts as factory

    • BPEL has already implicit creation model

  • BPEL Engine that is NOT OGSI Factory

    • Will not fit into common OGSI usage pattern

    • OGSI Factory is optional …

      * Aleksander Slomiski

Agenda

Background

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion


Wsrf support

Outline

WSRF Support *

  • WS-Addressing (WSA)

    • Workflow Instance identification

  • WSA is already used by BPEL …

    • No need to do conversions

  • WS-Resource properties

    • Similar to OGSI SDEs

  • WS-Notification

    • Monitoring workflow state

      * Aleksander Slomiski

Agenda

Background

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion


Integration with today grid

Outline

Integration with Today Grid *

  • GridFTP, GSI Security, Condor, …

  • Add set of pseudo partners (services)

    • No need to extend BPEL syntax!

    • They represent built-in functionality (handy!)

    • Can be implemented as real Web Services

  • Will make easy to write workflow that is:

    • Working on Grid (CoG services)

    • Manipulating components (XCAT)

    • Large data transfers (GridFTP, RFT service)

  • Similarly could have OGSI partners

    • Natively understands GSH/GSR/locator

    • Maintains soft state etc.

      * Aleksander Slomiski

Agenda

Background

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion


Additional issues

Outline

Additional Issues*

  • Workflow Monitoring

    • How much state exposed as XML is needed?

  • Fault Tolerance

    • Selection of alternative services

    • Dealing with “unexpected” exceptions

  • Supporting Large Data and Streaming

    • Suitable metaphor (in BPEL)?

      * Aleksander Slomiski

Agenda

Background

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion


On using bpel extensibility to implement ogsi and wsrf grid workflows

Outline

Questions?

Service Port Type

Factory Port Type

OGSI Grid Service

WSDL Port Type

BPEL Process

Agenda

Background

Smart Proxy

BPEL

BPEL / OGSI

BPEL / WSRF

Other Issues

Conclusion


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