A PPARC funded project

Common Execution Architecture

Paul HarrisonIVOA Interoperability MeetingCambridge MA23-28 May 2004

Apr 21, 2023 IVOA Interoperability Meeting: Common Execution Architecture 2

IntroductionCommon Execution Architecture (CEA)

An attempt to model how an application is run in the Virtual Observatory An application is any process that consumes

or produces data

Designed primarily to work in web services environment A set of schema and WSDL definitions

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MotivationTo create a model of an application VO infrastructure only has to deal with a single

application model Application writers know how to interface VO

Provide higher level description than WSDL Restrict to manageable subset Provide specific semantics for astronomical

Quantities Provide extra information - e.g. Defaults Data flow does not necessarily follow call tree

Asynchronous Operation

Apr 21, 2023 IVOA Interoperability Meeting: Common Execution Architecture 4

HistoryThe desire to be able to create a workflow Engine in AstroGridDerived from the Iteration 4 Command Line Application Controller experiences.

It is a work-in-progress Will definitely evolve in next few months

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Application Model

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ComponentsApplication Command line, web service

Common Execution Controller Controls the application, interacts with the

other components

Invoking process Workflow, web service, script

Monitoring Service Receives the status messages

Storage Service

Apr 21, 2023 IVOA Interoperability Meeting: Common Execution Architecture 7

Component InteractionsUML Sequence Diagram The monitoring service could be same as

invoking service The only guaranteed status message is the

final one The results of running the application are not

returned directly to the invoking process. The destination is implicit in the specification of the output parameters

Apr 21, 2023 IVOA Interoperability Meeting: Common Execution Architecture 8

How to use itAstroGrid Iteration 5 released at end of month Look at test environment!!

AstroGrid exposes all these components as web services Workflow is an xml document

Not limited to using AstroGrid portal Script Extend existing VO Tools (e.g. Aladin)

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Deployment ScenarioUML Diagram Command line applications that are wrapped

by specialized CommonExecutionControllers that make a compute farm

Web services proxy component that can act as an adapter between a generic web service and the CommonExecutionConnector interface

Web services proxy can be localised with a web service so that the results returned can be stored locally thus minimising network traffic

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How to integrate your Applications

Command Line Execution Controller already exists CEA web service wrapper for UNIX

command lines Interacts with workflow, MySpace Simply a case of configuring the application

in the registry If you want to wrap functionality easy to do by

extending the CommandLineApplication class.

Implement the CommonExecutionConnector Interface directly.

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SummaryCEA creates an environment to send messages to and from applications.

Implemented in AstroGrid Workflow with a CEC for Command Line applications Configuration only web service. Iteration 6 will produce general CEC proxy for

any web service.

See maven page http://www.astrogrid.org/maven/docs/

snapshot/applications/