Enterprise Applications With OSGi and SpringSource dm Server
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The document discusses the SpringSource DM Server, which leverages OSGi for modular application deployment in an enterprise context. It details the benefits of dynamic service handling, modularization, and various deployment options like OSGi bundles and PAR files. Additionally, it outlines the server's compatibility with existing Java EE applications and the roadmap for future enhancements.
![Export & Import Packages
Declare package-level visibility and
dependencies of your bundle.
Export-Package: com.xyz.bar
Export-Package: com.xyz.bar;version="1.0.5"
Import-Package: com.xyz.foo
Import-Package: >= 1.0.3; e.g.,
com.xyz.foo;version="1.0.3" 1.0.3, 1.0.3.GA,
Import-Package: 1.0.4, 2.0, etc.
com.xyz.foo;version="[1.0.3,1.0.3]"
Import-Package:
com.xyz.foo;version="[1.0.3,1.1.0)",
com.xyz.bar;version="[1.0.3,2.0.0)"
Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 13](https://image.slidesharecdn.com/enterpriseapplicationswithosgiandspringsourcedmserverjazoon2009ewolffsbrannen-124602735884-phpapp01/85/Enterprise-Applications-With-OSGi-and-SpringSource-dm-Server-13-320.jpg)
![Importing & Exporting Types
• Plain OSGi + …
• Import-Library and Import-Bundle
– Library imports bundle imports
– Bundle imports package imports
– OSGi runtime semantics remain the same
Import-Library:
org.springframework.spring;
version="[2.5.6,3.0)"
Import-Bundle:
com.springsource.org.hibernate;
version="[3.2.6.ga,3.2.6.ga]"
Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 28](https://image.slidesharecdn.com/enterpriseapplicationswithosgiandspringsourcedmserverjazoon2009ewolffsbrannen-124602735884-phpapp01/85/Enterprise-Applications-With-OSGi-and-SpringSource-dm-Server-28-320.jpg)
Enterprise Applications With OSGi and SpringSource dm Server
- 1. Enterprise Applications with OSGi and SpringSource dm Server Eberhard Wolff – SpringSource Sam Brannen – OpenCredo Jazoon – 24 June 2009 – Zürich, Switzerland Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited.
- 2. Eberhard.Wolff (@) SpringSource.com • Regional Director of German speaking countries and Principal Consultant • Author of several articles and books • First German book on Spring • Speaker at national and international conferences • Blog: http://jandiandme.blogspot.com/ Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 2
- 3. SpringSource • Employs most committers for Spring • Committers for Tomcat, ActiveMQ, Apache HTTP • New: tc Server / dm Server • Groovy / Grails • Hyperic • Training • Consulting • Subscription / Support Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 3
- 4. Sam.Brannen (@) OpenCredo.com • Software Consultant • Spring Framework Core Developer • Previous SpringSource dm Server developer: OSGi-enabled Web deployment models, Tomcat integration, Test Framework • Java developer with 10+ years' experience • Regular speaker at conferences on Spring, dm Server, Java, and testing • Co-author of Spring in a Nutshell; chief technical reviewer for Spring Recipes Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 4
- 5. Open Credo • Experts in Open Source application development • Consulting • Coaching • Management Training • Committers for numerous Spring projects – Spring Framework – Spring Integration – Spring .NET Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 5
- 6. Why another Application Server? Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited.
- 7. OSGi’s Promise of Modularity • Modularization is key to maintainable software • Application Server itself is modularized – No more "one size fits all" – Java EE 6 introduces profiles • On the client and in the embedded world OSGi has succeeded as a standard for modularization • OSGi enters the enterprise server market… Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 7
- 8. Building on OSGi • Almost all app server vendors base their systems on OSGi (JBoss, Sun, Oracle, IBM) • But none offers OSGi as a programming model for the customer • Why shouldn't the customer be as empowered as the app server vendor? • Enter SpringSource dm Server… Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 8
- 9. OSGi Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited.
- 10. It's a module system • Partition a system into a number of modules – "bundles" • Dynamic: bundles can be installed, started, stopped, uninstalled and updated – ...at runtime • better operations • Strict visibility rules • Resolution process satisfies dependencies of a module • Understands versioning Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 10
- 11. It's even service-oriented • Bundles can publish services… dynamically! • Service Registry allows other bundles to consume services • Services come and go at runtime – … transparently when using Spring-DM Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 11
- 12. OSGi Bundle • The fundamental unit of deployment and modularity in OSGi • Just a JAR file – with additional entries in META-INF/MANIFEST.MF • Common manifest headers: – Bundle-SymbolicName – Bundle-Version – Bundle-Name – Bundle-ManifestVersion – Bundle-Vendor Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 12
- 13. Export & Import Packages Declare package-level visibility and dependencies of your bundle. Export-Package: com.xyz.bar Export-Package: com.xyz.bar;version="1.0.5" Import-Package: com.xyz.foo Import-Package: >= 1.0.3; e.g., com.xyz.foo;version="1.0.3" 1.0.3, 1.0.3.GA, Import-Package: 1.0.4, 2.0, etc. com.xyz.foo;version="[1.0.3,1.0.3]" Import-Package: com.xyz.foo;version="[1.0.3,1.1.0)", com.xyz.bar;version="[1.0.3,2.0.0)" Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 13
- 14. Publish a Service ServiceRegistration reg = bundleContext.registerService( Bar.class.getName(), myBarService); ... reg.unregister(); Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 14
- 15. Consume a Service ServiceReference ref = bundleContext.getServiceReference( Bar.class.getName()); Bar bar = (Bar) bundleContext.getService(ref); ... bundleContext.ungetService(ref); // bar should no longer be used here Complex… Potential resource leaks! Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 15
- 16. OSGi in the Enterprise Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited.
- 17. OSGi as a Server Platform Web Application Enterprise Server Bundles Web Transaction ... OSGi Container Management Application Features might be added on demand OSGi Service Platform Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 17
- 18. OSGi for Enterprise Applications • Dynamic services are hard to develop (boiler plate code) • Basic infrastructure for OSGi + Web has to be done by yourself • What do we do about WARs? • How do you keep a service or type from leaking out of an application? – The notion of an application does not exist in OSGi… • Many enterprise libraries are not suited for OSGi Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 18
- 19. Enterprise Libraries under OSGi • Class and resource loading problems – class visibility – context class loader is undefined in OSGi – resources in META-INF –… • Not directly supported: libraries with multiple bundles Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 19
- 20. Example: Class Visibility Data Layer Data Layer Bundle Bundle Import-Package Import-Package Domain Model Domain Model Hibernate Hibernate Bundle Bundle Bundle Bundle <Export-Pkg> <Export-Pkg> <Export-Pkg> <Export-Pkg> Domain types & SessionFactory mapping files Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 20
- 21. Good News for OSGi in the Enterprise • Spring 2.5 and many other Spring projects are OSGi-ready – modules shipped as bundles – all class loading behaves correctly under OSGi • Hundreds of other enterprise libraries are now also packaged for use under OSGi in the SpringSource Enterprise Bundle Repository Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 21
- 22. Spring Dynamic Modules & SpringSource dm Server Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited.
- 23. Spring-DM: ApplicationContext • Configuration files in /META-INF/spring • Automatically merged • ..and an ApplicationContext is created – one per Bundle • Spring-DM manages the ApplicationContext lifecycle • OSGi manages the Bundle lifecycle Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 23
- 24. Spring-DM: Service Registry (1/2) Contrast with <beans ...> programmatic API <osgi:service ref="customerDAO" interface="dao.ICustomerDAO" /> <osgi:reference id="dataSource" interface="javax.sql.DataSource" /> </beans> Also supports filters, listeners, collections (lists and sets), etc. Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 24
- 25. Spring-DM: Service Registry (2/2) • Dynamic services handled automatically – Instances and collections are proxied – Method calls are buffered – Configurable timeouts • Purely declarative Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 25
- 26. Out-of-scope for Spring-DM • Easy import of bundles and libraries • Using JPA or Hibernate in OSGi • Seamless Web support • Notion of an application • Enter SpringSource dm Server… Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 26
- 27. dm Server Platform • Built on Equinox • Modular architecture –Subsystems –Bundles • Small footprint • Modular profiles • Bundle repository • Library provisioning • Serviceability –FFDC –Logging –Tracing Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 27
- 28. Importing & Exporting Types • Plain OSGi + … • Import-Library and Import-Bundle – Library imports bundle imports – Bundle imports package imports – OSGi runtime semantics remain the same Import-Library: org.springframework.spring; version="[2.5.6,3.0)" Import-Bundle: com.springsource.org.hibernate; version="[3.2.6.ga,3.2.6.ga]" Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 28
- 29. Example Application Bundles • Web Export Web • Service • API Import – Only interfaces and API domain classes – Implementation can be exchanged Service • Could add infrastructure: data source, transaction manager, etc. Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 29
- 30. Bundles & Types • Only dependencies on the API – Implementation can be exchanged, … even at runtime • No direct dependencies on any implementation • Not shown: dependencies on external bundles • … can be installed in dm Server • … modular middleware! Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 30
- 31. Bundles & Services Service Type: Web Registry Import consume Services: API Publish / Consume publish Service Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 31
- 32. Bundles & Services • Infrastructure can use the same principle as application services – DataSource and PlatformTransactionManager are just services Can I still run on plain Java EE? • Yes: instead of OSGi Service directly inject Spring Beans • No more dynamic services / modularization • No code change needed • Application can run on Java EE or OSGi Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 32
- 33. PAR • Packaging format for all modules in an app. • JAR with Application-* manifest headers • Single unit: deploy, refresh, undeploy • Application boundaries – Scoping of types / services – DataSource does not leak out of the application – Hibernate can change domain objects Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 33
- 34. Web Migration: From WAR to PAR Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited.
- 35. Web Application Deployment Options • Standard Java EE WAR – supported as is – converted into an OSGi bundle • Shared Libraries WAR – WAR + OSGi package imports – Eradicate library bloat of monolithic Java EE WARs • Shared Services WAR – Uses OSGi services with Spring's <osgi:reference> • Web Module Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 35
- 36. Web Module • Deployment & packaging option for OSGi- compliant web applications: stand-alone or within a PAR • OSGi bundle: structure similar to Shared Services WAR + MODULE-INF for resources • Reduced configuration for Spring MVC applications via Web manifest headers – Auto-configuration of Spring MVC's DispatcherServlet – Single WebApplicationContext and no Root WAC • Additional configuration via web.xml fragments Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 36
- 37. Web Manifest Headers Manifest-Version: 1.0 Bundle-ManifestVersion: 2 ... Module-Type: Web Web-ContextPath: /my-web-app Web-DispatcherServletUrlPatterns: *.do Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 37
- 38. DEMO Web Module Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 38
- 39. Roadmap Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited.
- 40. dm Server 2.0 Roadmap • SpringSource dm Server 2.0: 3rd quarter 2009 • Cloning bundles – Solves problems around static variables and more • Shared Repository – Share a single repository among several servers • Plan Files – Define an application as a collection of bundles – Does not contain the bundles, more flexible • Distributed and improved management – Operation on a group of servers – Like tc Server for Tomcat • Modular Web Applications Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 40
- 41. Support for Enterprise OSGi Standards • RFC 66: Web Container for OSGi (RI based on dm Server) • RFC 119: Distributed OSGi • RFC 124: Blueprint Service (RI based on Spring-DM) • RFC 139: JMX interface for OSGi • RFC 142: JNDI and OSGi integration Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 41
- 42. Summary Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited.
- 43. Summary: SpringSource dm Server • Based on proven, established modularization technology (OSGi) • Based on proven, established Web technology (Tomcat) • Spring and Spring-DM programming models: easy to use • Solves OSGi problems (e.g., context class loading) • Dynamic updates of running modules • Lightweight Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 43
- 44. Summary: Deployment Options • OSGi bundles • PAR = logical & physical application boundary • dm Server supports multiple Web deployment formats and therefore migration – Java EE WAR → Shared Libraries WAR → Shared Services WAR → Web Module Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 44
- 45. Resources • OSGi: http://osgi.org • Spring Framework: http://springframework.org • Spring-DM: http://springframework.org/osgi • SpringSource dm Server: http://springframework.org/dmserver • SpringSource Team Blog: http://blog.springsource.com • German Getting Started: http://www.dpunkt.de/buecher/3231.html • OpenCredo: http://opencredo.com Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited. 45
- 46. Questions? Eberhard Wolff Sam Brannen eberhard.wolff@springsource.com sam.brannen@opencredo.com http://SpringSource.com http://OpenCredo.com Copyright 2008-2009 SpringSource and Open Credo. Copying, publishing or distributing without express written permission is prohibited.