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Composite Applications: Can We Learn from Web Service Composition?

Ian Jones – Chair OASIS ebXML Messaging Services TC

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Outline Introduction History What we did? What are the issues? What are we doing next? What we learned? Questions

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Introduction

Chair OASIS ebXML Messaging Services TC

Day Job - Web Services, B2B & SOA International Standards Manager for BT

Almost 20 years in B2B EDI – EDIFACT & ANSI X.12 E-Commerce, Internet technology, EAI ebXML from the beginning Web services → SOA

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History ebXML Messaging Version 1

proprietary except SOAP 1.1 / SWA ebXML Messaging Version 2

Used XMLDSIG for security Not WS* compatible and no SOAP 1.2

Make V3 WS friendly, work with other WS-specs and support simple clients +++

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What We Did WS-Security 1.0 & 1.1 WS-Reliability WS-Reliable Messaging Not forgetting

SOAP 1.1 & SOAP 1.2 WSI –Attachments Profile & Basic

Security profile All the other underlying technology!

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Issues …

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Issues … Baggage The extra bits you get for free! Ignore some! Optional? Address some! Mandatory? Dependencies and sub specifications! Versioning – stability & upgrades Support – Specification and software

You have to Profile !

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Issues … Leftovers The bits you still need that did not fit! Custom build the bits? Ask your supplier to build? Where do they fit?

Extend an existing component Stand alone

Versioning & change

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Next!! Adding extra functionality

Custom extension – large payload handling

Bundling messages More transports

Extending functionality Reliable delivery via intermediaries

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What we learned Architecture & design

Pipeline (SOAP Processing model) Embedded Black box

Package / Component compatibility – what “flavour” do they implement

Unavailable header Data – someone else used it!

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The most important lesson

Compromise

And / OrChange

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What applies to Composite Applications? Due diligence – functionality,

interface and scope of component Cost – time, effort, money – building

the “glue” Error handling Test Fault fixing – non trivial if component

error

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Consider - 1 “just because something can be done

does not mean it should be done” You will probably be the first person

assembling this collections of components

Management – development / delivery /operational

Expect the unexpected

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The Spanish Inquisition

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Consider - 2 Sceptics and cynics are not always

wrong! Don’t believe everything you read or are

told – CHECK the documentation

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Final thoughts Moving data between applications

takes time Distributed components could move

Servers Continents What if it is outsourced?

SLA for the component Complexity are you reducing it?

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Questions / Comments / Discussion

Yes the last 10% takes 90% of the time!