moving the guidewire platform to osgi - paul d'albora

© Guidewire Software, Inc. All rights reserved. Do not distribute without permission.

Moving the Guidewire platform to OSGi

A case study

Paul D’AlboraGuidewire Software

[email protected] 2012

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Agenda• Introduction to the Guidewire platform

• Motivation for moving to OSGi

• Challenges

• Where we are and where we’re going

• Q & (hopefully) A

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The Guidewire Platform – Basics• Supports core system software for the global

property/casualty insurance industry

• Core services: ORM layer, web UI framework, business rules, workflow, automated upgrade, I18N, customer plugins, messaging and web services integration

• High degree of configurability

• Supports multiple JEE containers

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The Guidewire Platform – Pressures• Constantly adding and improving features for

applications

• Must not break existing customers

• Large code base developed over ten years

• Large and growing development team

• All of which can lead to …

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Goals• Test components in isolation

• Reduce learning curve

• Contain maintenance costs

• Release components independently

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OSGi• Module system

• Versioning

• Manageability

• Mature, well-defined specifications

• Robust community

• Services!

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Givens• Application must be delivered as a JEE application

(EAR/WAR)

• Code divided into coarse-grained “modules” forming a DAG of compile-time dependencies

• Non-Eclipse IDE (no PDE)

• Custom build system

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Step 1

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Plan• Run Equinox embedded in JEE container using

servlet bridge

• Define a bundle for each existing code “module”

• Replace/Convert 3rd-party jars with OSGi equivalents

• Get automated tests running in framework

• DON’T try to modularize yet

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Roadblocks

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Problem: Split Packages• Same package exists in multiple modules

• Framework binds to one of them, causing the other “parts” of the package to effectively disappear

• Typical for platform and one or more applications to define classes in the same package

• This is pervasive in our code

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Solution: Fragments• Define an empty “root” bundle

• Every bundle is a fragment of root- Fragment-Host: com.guidewire.root

• Simulates one bundle

• More closely represents original, non-modular, global classpath environment

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Problem: 3rd-party libraries• Lots of them (~102)

• Signed jars

• Classpath assumptions

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Solution: Varied• Public OSGi bundle repositories– Eclipse Orbit– SpringSource

• BND– For signed jars, embed jar within jar and use Bundle-

ClassPath– Can combine related jars to deal with split packages

• TCCL to work around classpath assumptions

• Newer jars being packaged as OSGi bundles

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Problem: Servlets• No longer registered in web.xml (just the servlet

bridge)

• How to register platform and application servlets with HttpService

• Ordering requirements (<load-on-startup>)

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Solution: Components• Felix Http Whiteboard

• Declarative Services with Bnd- @Component(provide=Servlet.class, properties="alias=/path")

• For ordering-dependent servlets, register in order with HttpService- Component with @Reference to HttpService

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Practical Tips• Learn and use BND

• Learn the classloading flow chart (R4.2 Spec, Fig 3.19)– Turn off osgi.compatibility.bootdelegation, osgi.context.bootdelegation in Equinox

– No Require-Bundle

• Lean on automated tests

• Use the framework itself

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Current Status• Applications and integration tests running successfully

in development

• Initial performance testing reveals no significant difference in response times or memory usage

• Rolled out to application teams with minimal disruption

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Next Steps• Define candidate areas for modularization

• Use services to de-couple components

• Use services to replace ad hoc registries

• Educate developers about service-oriented programming

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Example: Static Service Registry• Map of interface Class to implementation instance

• Initialized by bootstrap class

• Accessed via static methods

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Static Service Registry – Code Sample 1

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Static Service Registry – Replacement

Questions?

Feedback welcome.

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moving the guidewire platform to osgi - paul d'albora

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