OSGi DevCon 2012 Guidewire Software builds advanced applications for the insurance industry. With over a hundred customers in a dozen countries, including global giants like AXA, Geico, and Tokyo Marine, our applications handle tens of billions of dollars worth of business every year. The Guidewire platform provides core services to its applications, and is oriented toward a high degree of customer extensibility. This talk is about the first phase of our project to migrate the Guidewire platform to OSGi. We describe our motivations for moving to OSGi, challenges we faced in "getting off the ground," and how we expect to take advantage of OSGi. Topics include: Using bnd to build OSGi metadata Using fragments to create an initial "mega bundle" Embedding an OSGi container inside a J2EE app server Bundling 3rd-party jars Using Declarative Services as our component model Integrating tools like bnd into a custom build and development environment We also discuss how we plan to leverage OSGi, including: Replacing a proprietary plugin architecture with OSGi services Reducing the cognitive burden within development through truly separate components Enabling testing in isolation, both at the class level and at the bundle level

1. © Guidewire Software, Inc. All rights reserved. Do not distribute without permission.
Moving the Guidewire platform to
OSGi
A case study
Paul D’Albora
Guidewire Software
pdalbora@guidewire.com
March 2012

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© Guidewire Software, Inc. All rights reserved. Do not distribute without permission.
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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© Guidewire Software, Inc. All rights reserved. Do not distribute without permission.
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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© Guidewire Software, Inc. All rights reserved. Do not distribute without permission.
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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© Guidewire Software, Inc. All rights reserved. Do not distribute without permission.
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 – Code Sample 2

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Static Service Registry – Code Sample 3

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Static Service Registry – Replacement

27. Questions?
Feedback welcome.

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