Migrate OpenMRS from proprietary module framework to OSGi framework

I am very interested with this story and would like to participate. The immediate benefits that I can think of are:
1. better dependency management. a library with multiple versions can coexist.
2. better life cycle management. deploying, upgrading, uninstalling a module is feasible without affecting other services

Hey Fred

Thanks for the comment on that ticket. We had a conversation about this
with one of the Eclipse OSGi (aka Equinox) architects about a year ago,
but I'm not sure what the current state of that conversation is. I'm
including Burke, Ben and Darius for their comments (I'm hoping this adds
them as a watcher on the ticket). Otherwise, they can just head over to
ticket TRUNK-1596.

http://tickets.openmrs.org/browse/TRUNK-1596

Justin

We are still in the "how feasible is this" stage. Ideally we would be able to support modules in a backwards compatible way. See the Atlassian plugin/module system for their conversion to an osgi wrapper framework from a custom one.

(I had to add Burke, Darius, and myself as watchers manually)

Hi All. This looks interesting and potentially quite difficult. I was wondering if there were any description of the current module engine (I did not seem to find one per se).

It seems to be quite highly regarded in the open source medical software world (my apologies I cannot find the link at which I was looking so I cannot include here).

Thank you
Misha

The only documentation is at http://wiki.openmrs.org/display/docs/Creating+Modules

Hi All:

I've been looking into this quite a bit.

As far as backwards compatibility Ben is referring, I believe, to:
http://confluence.atlassian.com/display/PLUGINFRAMEWORK/Going+from+Plugin+to+OSGi+Bundle

I have tried to find "shortcuts" and there seem to be a few options (especially if we limit to Spring dm Server, which
I know Ben prefers not to - and I agree) but nothing yet that I have found that I believe would solve the problem.

However, I had a more important question. Is this ticket really:
1) "Migrate OpenMRS from proprietary module framework to OSGi framework." To me this implies that what we want is to make
OpenMRS modules OSGi bundles. This is fine in principle but I'm not clear on what the advantage of this is over a proprietary
system that works, especially if we're trying to make it backwards-compatible to the current system? I looked at the Atlassian
system in brief and it seems like they just use their atlassian-plugin.xml to make a full OSGi bundle, which is all good but seems
to just add another layer of complexity.
OR
2) "Migrate OpenMRS to consist of bundles and run on top of an OSGi framework." Now this would definitely be interesting, as this would
make all parts of OpenMRS pluggable and might actually be a good idea in the long term. Of course, this would be much more difficult but
this seems like a worthwhile long-term task, in any case.

Thank you
Misha

Hi Misha,

I'm definitely more interested in seeing #2. In theory OpenMRS 2.0, which
would include a completely-rewritten-from-scratch user interface, could also
have its module infrastructure completely rewritten to use OSGI.

-Darius

On Sun, Oct 10, 2010 at 11:45 AM, Misha Koshelev (JIRA) <

Yes, its more the latter than the former.

On Sun, Oct 10, 2010 at 2:45 PM, Misha Koshelev (JIRA) <

Thanks. There seem to be some fairly straightforward ways to migrate, e.g.:
http://static.springsource.org/osgi/docs/1atest/reference/html/web.html#web:spring-mvc
http://raibledesigns.com/rd/entry/running_spring_mvc_web_applications

but none of it seems to work at the moment

at least with:
http://www.springsource.com/products/dmserver

Misha

If we were to switch from using the static Context with services to true DI
using spring this might be easier. I need to raise this as a request for
some sweeping 2.0 changes.

On Mon, Oct 11, 2010 at 6:30 PM, Misha Koshelev (JIRA) <

Eclipse Virgo would be an good choice for OSGI frameworks:
http://www.springsource.org/node/2861

Fyi, just wanted to note something with which I was confused (and perhaps others are too) with regards to converting Spring MVC applications to use OSGi, at least per:
http://static.springsource.org/osgi/docs/1atest/reference/html/web.html#web:spring-mvc

Notably, the breakthrough I finally had with these instructions is to understand that - currently we have:
1) a web container (Tomcat, Jetty, etc.)
2) we run OpenMRS within this container
3) we have modules
1-2-3

In these instructions we have the following layout:
1) an OSGi framework (Equinox, Felix, etc. - Spring DM server, e.g., has an underlying equinox, I think there is one more but I cannot recall its name off the top my head )
2a) a web container running within the OSGi framework
2b) OpenMRS
2c) OpenMRS modules (not 100% sure about placement of 2c below)

Something like:
2a
/
1-2c
\
2b

roughly, not:
1-2a-2b-2c

and there is no toplevel Web container.

So we would no longer, in this case, deploy OpenMRS in a Web container at all. If we stuck with Spring MVC and used the option described
http://static.springsource.org/osgi/docs/1atest/reference/html/web.html#web:spring-mvc
we would provide our own web container within the OSGi framework.

In other words, we wouldn't really need the user to install anything else except MySQL. No Tomcat, no Jetty, no Spring DM Server, etc.

Personally this approach is kind of neat to me, but just my 2 cents.

Interesting. Presumably you could support multiple possible web containers,
if some implementations really want to use tomcat/jetty/glassfish/jboss/etc?

-Darius

On Tue, Oct 12, 2010 at 9:38 AM, Misha Koshelev (JIRA) <

Yes Darius. I noticed Atlassian also has both a standalone version with Tomcat and a WAR version:
http://www.atlassian.com/software/confluence/ConfluenceDownloadCenter.jspa

Btw since you guys like their framework, here are a few more facts.

1) They use felix.

wget -c http://wpc.29c4.edgecastcdn.net/8029C4/downloads/software/confluence/downloads/confluence-3.4-std.tar.gz
tar xvzf confluence*
find confluence* -name *felix*.jar
confluence-3.4-std/confluence/WEB-INF/lib/org.apache.felix.framework-3.0.2.jar

2) More importantly - their framework is available for embedding through, e.g., maven:
http://confluence.atlassian.com/display/PLUGINFRAMEWORK/Quick+Start+Guide+to+Embedding
and it is, to my understanding, freely available for our use:
http://confluence.atlassian.com/display/PLUGINFRAMEWORK/License+and+Copyright+for+the+Atlassian+Plugin+Framework

I don't know if this license is compatible with ours, but some options would be:
a) their framework works. It is obviously well developed. Yes we would break compatibility with existing plug-ins but why not just adopt the framework?
or
b) take their framework and hack it to work with our module architecture. This may be best of both worlds if we're really trying to preserve backwards compatibility.

Just my 2 cents

Thank you
Misha

—

ADDENDUM:
Trying to do some work on making OpenMRS run in an OSGi environment:
http://stackoverflow.com/questions/3955222/unable-to-locate-spring-namespacehandler-springs-mvc-basic-in-equinox-using-ma

Some other alternatives for modular web applications with Spring MVC:

• Impala
  http://code.google.com/p/impala/
  not yet OSGi http://code.google.com/p/impala/wiki/OSGiConvergence
• Spring Slices
  http://blog.springsource.com/2009/06/22/modular-web-applications-with-springsource-slices/
  requires dm server

Ideas re OSGi-fication of Spring MVC web application (high level):
http://stackoverflow.com/questions/126073/modular-web-apps

Misha, are you working on this? (If so, assign it to yourself.)

Hi Darius:

I actually even bought a Spring DM book too... but no promises.

I can't assign it because it says "Needs Design" at the top and there is no assignment button.

Misha

p.s. I can't make any promises as this is a significant feature/project as stated.

Hi Misha,

That's okay, you're not committing to implementing this whole feature, but
we really appreciate you investigating it.

-Darius

On Mon, Oct 18, 2010 at 5:40 PM, Misha Koshelev (JIRA) <

Hi Darius et al:

Thank you so much for your understanding that I probably can't necessairly implement the whole ticket.

On a more practical note, there is no button to press to assign to myself.

Misha

Ok, I hate to say it but I'm stuck... and not sure how to proceed

Basically, to test, first apply this patch.

Make the osgi specific files using:
mvn clean install -P osgi
which means we use the "osgi" profile.

This will generate osgi bundles (jars) in api/target/classes/osgi, web/target/classes/osgi, wrapped osgi libraries for which there are currently no osgi bundles in osgi/target/classes (jars), and an osgi WAR in webapp/target/classes/osgi.

Now, in osgi/, you will find a shell script called run.

You will need pax runner:
http://paxrunner.ops4j.org/display/paxrunner/Download

There are maven specific ways to do this:
http://www.ops4j.org/projects/pax/construct/help/provision.html

but currently this would be very complicated without changing all the dependencies to the osgi-specific versions from:
http://www.springsource.com/repository/app/
http://www.springsource.com/repository/app/faq#q8
(and makes no sense until this actually works at least in some implementation)

You will have to change /home/misha/workspace/trunk to point to your openmrs folder in the osgi/openmrs.bundles file (sorry - again there is no point in changing this until OpenMRS actually somehow works in an OSGi container).

Now simply run the shell script run. It will download dependencies from relevant maven repos, and start equinox with everything loaded.

The good:
1) we are able to load both the api and web bundles and they all resolve successfully either with actual OSGi bundles that are in openmrs.bundles or OSGi-fied bundles from the osgi module
2) the webapp loads "fine" in terms of OSGi bundle-space

The bad:
1) There are some serious resolution problems with the webapp. I don't know how to fix them and don't really understand very well the class loading going on with the spring web extender loading the Web app.
http://static.springsource.org/osgi/docs/current/reference/html/web.html
I have tried even simple DynamicImport-Package
http://blog-o-lok.blogspot.com/2008/01/osgi-and-dynamicimport-package.html
but from what I can tell the spring classloader expects the war to actually contain all dependencies? However, even if I do this it doesn't help as then we have conflicts between the jars that Spring DM references and those that OpenMRS does (I believe).

Additionally, since we have separate jars for api and web (as opposed to webapp), and the maven bundle plugin doesn't "officially" support wars
http://wiki.ops4j.org/display/ops4j/Getting+the+benefits+of+maven-bundle-plugin+in+other+project+types
automatic scanning of imports in our webapp package doesn't work

I tried bundlor
http://static.springsource.org/s2-bundlor/1.0.x/user-guide/htmlsingle/user-guide.html
but it doesn't seem to work any better

For reference, I am also attaching equinox log from the current version of patch as attached. Perhaps some OSGi guru might be able to help.

As for
http://stackoverflow.com/questions/3955222/unable-to-locate-spring-namespacehandler-springs-mvc-basic-in-equinox-using-ma
we don't seem to encounter this issue in OpenMRS, so its probably not worth investigating (or at least we don't yet...).

Looking forward to potential OSGi expert advice.

Yours
Misha

Matt et al: maybe there is some way to artifically (automatically) flatten a multi-module pom like OpenMRS into one pom that just makes the war? This would really help with testing I believe for OSGi-ification.

Thx
Misha

Turns out it was a problem with imported classes for wrapper JARs that are not available as OSGi bundles. Now it starts up without error - albeit doesn't work (i.e., no pages seem to open )

Baby steps!

On Thu, Oct 21, 2010 at 6:14 PM, Misha Koshelev (JIRA) <

Thanks for the encouragement. I have adapted to use Jetty (in a still non-functional state but all resolves) which is a bit simpler.

I am afraid I will be out of town tomorrow - late Sunday and so will be unable to make any further progress during that time.

Thank you
Misha

Slightly better results. Logging package from web-console Spring DM demo has been disabled, so logging is simply redirected to a file, but this helps see that there was an error when not making openmrs-api and openmrs-api as fragments of webapp. As fragments of webapp, we now get farther: we can complete GUI to create OpenMRS database, but database creation fails. To see why it fails, we will need to make a fragment of log4j, i.e.:
Fragment-Host: org.springframework.osgi.log4j.osgi
in the MANIFEST.MF. Currently web-console uses a log4j.properties file, not log4j.xml. Will test this behavior too.

1. all paths now relative
2. include log4j fragment (thus it is now totally self-sufficient, no need for web-console Spring DM demo)

Should work post-patch application with:
mvn clean install -P osgi
in trunk folder, followed by:
cd osgi
./run

Misha

(note svn:executable property will not be set by patch so this will need to be manually applied, i.e.,
cd osgi
svn propset svn:executable ON run
)

Next step: make liquibase sub-module of osgi module that exports all packages as otherwise we have problems in database creation.

Added liquibase changes (via fragment). Seems to be generating OpenMRS database (from within OSGi environment!!!!) as we speak

Good news: setup seems to work.
Bad news: after all this work, we arrive at the same error as we did with mvc-basic example OSGi-fication –

ERROR - Context.getServiceContext(255) |2010-10-26 15:30:34,775| serviceContext is null. Creating new ServiceContext()
ERROR - ContextLoader.initWebApplicationContext(220) |2010-10-26 16:02:04,174| Context initialization failed
org.springframework.beans.factory.parsing.BeanDefinitionParsingException: Configuration problem: Unable to locate Spring NamespaceHandler for XML schema namespace http://www.springframework.org/schema/util
Offending resource: class path resource [applicationContext-service.xml]

at org.springframework.beans.factory.parsing.FailFastProblemReporter.error(FailFastProblemReporter.java:68)
at org.springframework.beans.factory.parsing.ReaderContext.error(ReaderContext.java:85)
at org.springframework.beans.factory.parsing.ReaderContext.error(ReaderContext.java:80)
at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.error(BeanDefinitionParserDelegate.java:284)
at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.parseCustomElement(BeanDefinitionParserDelegate.java:1332)
at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.parseCustomElement(BeanDefinitionParserDelegate.java:1325)
at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.parseBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:136)
at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.registerBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:93)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.registerBeanDefinitions(XmlBeanDefinitionReader.java:493)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:390)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:334)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:302)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:143)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:178)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:149)
at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:124)
at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:93)
at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:130)
at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:465)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:395)
at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:276)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:197)
at org.openmrs.web.filter.initialization.InitializationFilter$InitializationCompletion$1.run(InitializationFilter.java:944)
at java.lang.Thread.run(Thread.java:662)

EDIT: Progress, got mvc-basic to work in OSGi at least
http://stackoverflow.com/questions/3955222/unable-to-locate-spring-namespacehandler-springs-mvc-basic-in-equinox-using-ma/4029589#4029589

Is this a problem with our application context? Can you try taking out some
stuff little by little and see what it takes to get things to start up?
Perhaps it doesn't work with spring 3? (or spring 2.5+ since thats when the
util schema was added)

On Tue, Oct 26, 2010 at 10:40 PM, Misha Koshelev (JIRA) <

Thanks for helpful suggestions Ben.

As you can see per my solution for making mvc-basic OSGi friendly:
http://stackoverflow.com/questions/3955222/unable-to-locate-spring-namespacehandler-springs-mvc-basic-in-equinox-using-ma/4029589#4029589

we will have to use
OsgiBundleXmlWebApplicationContext

This gets us farther.

java.lang.NoClassDefFoundError: javax/transaction/TransactionManager

Will investigate.

Yours
Misha

More progress, new error:
java.lang.ClassCastException: org.springframework.osgi.web.context.support.OsgiBundleXmlWebApplicationContext cannot be cast to org.springframework.web.context.support.XmlWebApplicationContext
at org.openmrs.module.web.WebModuleUtil.refreshWAC(WebModuleUtil.java:786)

Matt, quick question - what is the difference between
org.openmrs.hibernate_3.2.5.ga-mod
and the ga version (unmodified)?

Thank you
Misha

The modified Hibernate jar has a tiny fix which allows us to use a custom
identifier generator strategy, which we only use for concepts.

If you need to switch back to the vanilla Hibernate JAR for test purposes
that's totally fine.

The only difference is that if you create a concept through the API, and
you manually specify the ID you want the newly-created concept to have, then
that won't work with the vanilla Hibernate JAR. (You definitely won't need
to do this during your testing.)

-Darius

On Wed, Oct 27, 2010 at 8:11 PM, Misha Koshelev (JIRA) <

Works under OSGI! (step 1 - finally)

To try it yourself (you don't need anything besides svn and mvn installed):
svn checkout http://svn.openmrs.org/openmrs/trunk && cd trunk && patch -p0 < ../1596-complains-but-works-in-osgi.patch && mvn clean install -P osgi && cd osgi && bash run

Yay!

Misha

TODO: Dynamically change web.xml's:
<servlet>
<servlet-name>openmrs_static_content</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!-- Don't use "load-on-startup" in case initial setup wizard is needed -->
</servlet>
to use OsgiBundleXmlWebApplicationContext

Mostly works. Simplified and proofread.

Next steps are probably, in no particular order:
1) Migrate from pax runner to a Maven based framework (maven-pax-pluging) so that we don't have hardcoded dependency versions (this is not straightforward as the OSGi dependencies in the SpringSource Enterprise Bundle repositories have different groupId and artifactId's than the non-OSGi versions)
2) Stop having API and Web as Fragment-Host's of webapp for "proper" dependency resolution (I'm not 100% convinced this is necessary, since webapp is almost a skeleton war that depends highly on API and Web)
3) Stop using Dynamic-ImportPackage in webapp, instead have "proper" OSGi Import-Package statements (this may make a performance hit, but is technically not "kosher")

Then we need to somehow start exporting services in an OSGi friendly way so that we can move modules out from within OpenMRS to OSGi bundles (this is a big one and I have not investigated this yet).

At some point, probably the issue of deployment has to be decided. We can deploy in a standard container in principle (i.e., we have a WAR that deploys within Tomcat/Jetty/etc that then has an embedded Equinox that then does what we're doing now but there are some major potential caveats:
a) I don't know if Spring DM web extender will work at all in such a setup. It does not seem like it from my research - at the very least, not without some major changes. But I am not sure.
b) This seems somewhat unnecessary since, at the very least, people can run Tomcat and Jetty within the Equinox bundle and both as supported by Spring DM.
)

We get the following error, but I cannot notice any change in behavior, so I'm not sure it's meaningful (if anyone has ideas pls let me know):
INFO - FrameworkServlet.initServletBean(301) |2010-10-29 14:07:28,967| FrameworkServlet 'openmrs': initialization started
INFO - FrameworkServlet.initServletBean(320) |2010-10-29 14:07:29,010| FrameworkServlet 'openmrs': initialization completed in 42 ms
ERROR - MutableResourceBundleMessageSource.findPropertiesFiles(323) |2010-10-29 14:07:33,404| Error generated
java.io.FileNotFoundException: OSGi resource[/WEB-INF/|bnd.id=76|bnd.sym=org.openmrs.web.openmrs-webapp] cannot be resolved to absolute file path
at org.springframework.osgi.io.OsgiBundleResource.getFile(OsgiBundleResource.java:345)
at org.openmrs.messagesource.impl.MutableResourceBundleMessageSource.findPropertiesFiles(MutableResourceBundleMessageSource.java:311)
at org.openmrs.messagesource.impl.MutableResourceBundleMessageSource.findLocales(MutableResourceBundleMessageSource.java:93)
at org.openmrs.messagesource.impl.MutableResourceBundleMessageSource.getLocales(MutableResourceBundleMessageSource.java:70)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:309)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
at $Proxy75.getLocales(Unknown Source)
at org.openmrs.messagesource.impl.MessageSourceServiceImpl.getLocales(MessageSourceServiceImpl.java:84)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:309)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.openmrs.aop.LoggingAdvice.invoke(LoggingAdvice.java:114)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:50)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:50)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
at $Proxy74.getLocales(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:309)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
at $Proxy116.getLocales(Unknown Source)
at org.openmrs.api.impl.AdministrationServiceImpl.getPresentationLocales(AdministrationServiceImpl.java:989)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:309)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
at $Proxy76.getPresentationLocales(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:309)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.openmrs.aop.LoggingAdvice.invoke(LoggingAdvice.java:114)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:50)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:50)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
at $Proxy95.getPresentationLocales(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:309)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
at $Proxy95.getPresentationLocales(Unknown Source)
at org.apache.jsp.WEB_002dINF.view.index_jsp._jspService(index_jsp.java:594)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:328)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:315)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1093)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:70)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:70)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:360)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:726)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
at org.mortbay.jetty.servlet.Dispatcher.forward(Dispatcher.java:285)
at org.mortbay.jetty.servlet.Dispatcher.forward(Dispatcher.java:126)
at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:250)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1060)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:798)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:716)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:549)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1093)
at org.openmrs.module.web.filter.ForcePasswordChangeFilter.doFilter(ForcePasswordChangeFilter.java:65)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.openmrs.web.filter.GZIPFilter.doFilterInternal(GZIPFilter.java:60)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.openmrs.module.web.filter.ModuleFilterChain.doFilter(ModuleFilterChain.java:76)
at org.openmrs.module.web.filter.ModuleFilter.doFilter(ModuleFilter.java:58)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.openmrs.web.filter.OpenmrsFilter.doFilterInternal(OpenmrsFilter.java:112)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.openmrs.web.filter.StartupFilter.doFilter(StartupFilter.java:83)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.openmrs.web.filter.StartupFilter.doFilter(StartupFilter.java:83)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.openmrs.web.filter.StartupFilter.doFilter(StartupFilter.java:83)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:360)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:726)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:206)
at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:324)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:828)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:514)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395)
at org.mortbay.thread.BoundedThreadPool$PoolThread.run(BoundedThreadPool.java:450)
Caused by: java.io.FileNotFoundException: OSGi resource[/WEB-INF/|bnd.id=76|bnd.sym=org.openmrs.web.openmrs-webapp] cannot be resolved to absolute file path because it does not reside in the file system: bundleentry://76.fwk380254118/WEB-INF/
at org.springframework.util.ResourceUtils.getFile(ResourceUtils.java:242)
at org.springframework.osgi.io.OsgiBundleResource.getFile(OsgiBundleResource.java:342)
... 153 more

I thought I read somewhere (or was told) that it should be possible to
either bundle our war with an equinox jar or something else so that people
wouldn't have to modify their tomcat installations. Is that not the case?

On Fri, Oct 29, 2010 at 7:37 PM, Misha Koshelev (JIRA) <

QUICK UPDATE 3: It turns out that we are not processing JSP pages at all favicon.ico, I suspect, comes somewhere from the Felix HTTP Service itself. We can tell this as follows. By retrieving a non-existent URL, e.g., /111, we still look for favicon.ico.
WARN - DispatcherServlet.noHandlerFound(962) |2010-11-07 13:53:23,218| No mapping found for HTTP request with URI [/111] in DispatcherServlet with name 'servlet_4'
WARN - DispatcherServlet.noHandlerFound(962) |2010-11-07 13:53:23,319| No mapping found for HTTP request with URI [/favicon.ico] in DispatcherServlet with name 'servlet_4'

I am looking at this Jsp solution (from Equinox):
http://www.eclipse.org/equinox/server/jsp_support.php

QUICK UPDATE 2 (IDEA): Another thing that we could try - not elegant at all - would be simply having a "dumb" HTTP proxy to the server running inside OSGi. Not sure how well this would work (if at all), but just a thought...

QUICK UPDATE: There does not seem to be a "proper" way to do this that I could find (e.g., to change deployment from / to /openmrs), but I can fix it by wrapping ServletContext as so:
http://gist.github.com/659219
which gets us farther.

See also my third reply here:
http://old.nabble.com/ServletContext.getContextPath()-returning-%22-%22-in-in-org.apache.felix.http.jetty-2.0.4-to30101270.html#a30110490
—

Hi Ben et al:

I am indeed looking into the possibility of deploying within a traditional WAR file.

— MY PROGRESS —

http://gist.github.com/658734

— MY IMPEDIMENT —

http://old.nabble.com/ServletContext.getContextPath()-returning-%22-%22-in-in-org.apache.felix.http.jetty-2.0.4-to30101270.html

— INTRODUCTION: OSGI PROXY —

What you are really talking about, I believe, is a "proxy" of sorts, i.e.:

Tomcat/Jetty/etc. -> WAR -> OSGi platform -> OpenMRS running within OSGi platform handling request of WAR

(see, e.g.,
http://tinyurl.com/2fp9n4n
http://heapdump.wordpress.com/2010/03/25/osgi-enabled-war/
)

Spring DM does not seem to support this using their Web Extender:
http://static.springsource.org/osgi/docs/current/reference/html/web.html#web:osgi-artifacts:containers
"Spring-DM web support expects the web containers to be installed as OSGi services." (i.e., within the OSGi platform above)
Also see:
http://forum.springsource.org/archive/index.php/t-53629.html
See bottom for comment from Costin Leau:
"On the other hand, the use of servlet bridge forces the bundles to be pre-parsed so that the dispatcher/proxy servlet is instructed to do the proper redirects (like http service) which is not the approach that Spring-DM takes. Ideally, you should expose Tomcat as a service inside the embedded OSGi but that requires some work."

Spring DM's implementation seems non-standard, and ideally it would be nice to use the standard OSGi HTTP service (see below).

— OSGI HTTP SERVICE AND IMPLEMENTATION COMPARISONS — (ANY THAT I AM MISSING???)

http://www.osgi.org/javadoc/r4v42/org/osgi/service/http/HttpService.html
Default OSGI 4.2 HTTP SERVICE allow only registering of Servlets and Resources (not Filters, ServletContextListener's, etc.)

1. (CURRENTLY PREFERRED) Apache Felix HTTP Service
http://felix.apache.org/site/apache-felix-http-service.html)

Benefits:

• built-in Filter support
  http://felix.apache.org/site/apache-felix-http-service.html#ApacheFelixHTTPService-UsingtheExtHttpService
• example of embedding within a WAR file, as Ben suggests
  http://svn.apache.org/viewvc/felix/releases/org.apache.felix.http-2.0.4/samples/bridge/
• proxying support seems to be present (untested by myself)
  http://felix.apache.org/site/apache-felix-http-service.html#ApacheFelixHTTPService-UsingtheServletBridge
  http://svn.apache.org/viewvc/felix/releases/org.apache.felix.http-2.0.4/proxy/src/main/java/org/apache/felix/http/proxy/ProxyServlet.java?view=markup

Drawbacks:

• no ServletContextListener support, can be hacked
  http://www.eclipsezone.com/eclipse/forums/t84313.html#92063353

2. Pax Web
http://wiki.ops4j.org/display/paxweb/Pax+Web

Benefits:

• offer ServletContextListener support

Drawbacks:

• I was not able to find proxying feature support at all

3. Eclipse Equinox

Benefits:

• proxying support:
  http://www.eclipse.org/equinox/server/http_in_equinox.php, at least per the existence of
  http://www.eclipse.org/equinox/server/downloads/equinoxhttp-anon-proxy.psf), but they seem to offer a vanilla OSGi HTTP service

Drawbacks:

• only vanilla HTTP service support, no filter, etc. registration; see bottom of post and below link:
  http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.equinox/compendium/bundles/org.eclipse.equinox.http/src/org/eclipse/equinox/http/HttpService.java?view=markup&root=RT_Project

— ADDITIONAL IMPEDIMENTS: MAVEN (MATT BLANCHETTE - COMMENTS???) —

http://lists.ops4j.org/pipermail/general/2010q4/004787.html

The BIG problem seems to be for maintainability that there doesn't seem to be a way to really link our Maven dependencies to what gets provisioned (installed) within the OSGi framework:
1) the artifactId is different for OSGi vs non-OSGi bundles - e.g., javax.servlet for non-OSGi vs com.springsource.javax.servlet for OSGi
2) even though there is a mechanism, at least on the SpringSource Enterprise repository to track OSGi bundle dependencies, e.g.:
http://ebr.springsource.com/repository/app/bundle/version/dependencies?name=com.springsource.org.hibernate&version=3.2.6.ga
there does not seem to be a way to automatically resolve those dependencies when provisioning, i.e.:
http://stackoverflow.com/questions/3947618/automated-osgi-dependency-resolution-for-bundles-that-are-maven-accessible
Current options are:

2a) PAX Runner (CURRENTLY USING):
http://paxrunner.ops4j.org/space/Provision+bundles+from+a+text+file
2b) Pax construct's (= maven-pax-plugin's pax:provision goal)
http://www.ops4j.org/projects/pax/construct/maven-pax-plugin/provision-mojo.html
however, we still do not get automatic dependency resolution:
http://lists.ops4j.org/pipermail/general/2010q4/004787.html
or per 1) we can't link to our Maven dependencies anyway, so it seems like we're just making more hurdle by making what really is a text file into a glorified pom.xml (sorry if I am being harsh here)
2c) Apache Karaf provisioning:
http://felix.apache.org/site/46-provisioning.html
but this is pretty much exactly the same as Pax Runner

— SUPPORT THAT EQUINOX HTTP ONLY SUPPORTS SERVLET REGISTRATION, NOT FILTERS OR LISTENERS —

Fyi, HttpListener:
http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.equinox/compendium/bundles/org.eclipse.equinox.http/src/org/eclipse/equinox/http/HttpListener.java?view=markup&revision=1.6&root=RT_Project
seems to be something else entirely, not a servlet listener.

cvs -d :pserver:anonymous@dev.eclipse.org:/cvsroot/rt checkout org.eclipse.equinox/compendium/bundles/org.eclipse.equinox.http
...
SEARCH FOR FILTER find org.eclipse.equinox/ -name *.java -exec grep filter {} \; -print
SEARCH FOR LISTENER find org.eclipse.equinox/ -name *.java -exec grep listener {} \; -print

• thread pool and the listeners and responds to configuration changes.
  Enumeration listeners = configuredListeners.elements();
  while (listeners.hasMoreElements()) {
  HttpListener listener = (HttpListener) listeners.nextElement();
  listener.close();
  HttpListener listener = (HttpListener) configuredListeners.get(pid);
  if (listener != null) {
  listener.setProperties(properties);
  listener = new HttpListener(http, HttpConfiguration.this, properties);
  configuredListeners.put(pid, listener);
  HttpListener listener = (HttpListener) configuredListeners.remove(pid);
  if (listener != null) {
  listener.close();
  org.eclipse.equinox/compendium/bundles/org.eclipse.equinox.http/src/org/eclipse/equinox/http/HttpConfiguration.java
  protected HttpListener listener;
  public ServletContextImpl(Http http, HttpListener listener, HttpContext httpContext) {
  this.listener = listener;
  Registration reg = listener.getRegistration(uripath);
  Registration reg = listener.getRegistration(urlpath);
  org.eclipse.equinox/compendium/bundles/org.eclipse.equinox.http/src/org/eclipse/equinox/http/servlet/ServletContextImpl.java
  private HttpListener listener;
  HttpService(HttpListener listener, Bundle bundle) {
  this.listener = listener;
  listener.destroyBundle(bundle);
  listener = null;
  HttpListener tempListener = this.listener;
  HttpListener tempListener = this.listener;
  HttpListener tempListener = this.listener;
  HttpListener tempListener = this.listener;
  org.eclipse.equinox/compendium/bundles/org.eclipse.equinox.http/src/org/eclipse/equinox/http/HttpService.java
  /** ServerSocket upon which this listener operates */
  org.eclipse.equinox/compendium/bundles/org.eclipse.equinox.http/src/org/eclipse/equinox/http/HttpListener.java
  private final HttpListener listener;
  public HttpConnection(Http http, HttpListener listenerParam, SocketInterface socketParam, int socketTimeout) {
  this.listener = listenerParam;
  listener.handleConnection(socket);
  org.eclipse.equinox/compendium/bundles/org.eclipse.equinox.http/src/org/eclipse/equinox/http/HttpConnection.java

SEARCH FOR REGISTER find org.eclipse.equinox/ -name *.java -exec grep register {} \; -print

• a resource registered by this registration.
  //registered directory (the file was not directly registered itself).
  // The file we re looking for is the registered resource (alias) + the rest of the
  // filename that is not part of the registered resource. For example, if we export
  org.eclipse.equinox/compendium/bundles/org.eclipse.equinox.http/src/org/eclipse/equinox/http/ResourceRegistration.java
  registerManagedService();
  registerManagedServiceFactory();
  protected void registerManagedService() {
  managedService = http.context.registerService(ManagedService.class.getName(), this, properties);
  protected void registerManagedServiceFactory() {
  managedServiceFactory = http.context.registerService(ManagedServiceFactory.class.getName(), this, properties);
  managedService.unregister();
  managedServiceFactory.unregister();
• <p>If the factory instance is registered with the Framework, then
• registered with the service registry, it should be unregistered.
  org.eclipse.equinox/compendium/bundles/org.eclipse.equinox.http/src/org/eclipse/equinox/http/HttpConfiguration.java
  public void registerResources(String alias, String name, HttpContext httpContext) throws NamespaceException {
  tempListener.registerResources(bundle, alias, name, httpContext);
  public void registerServlet(String alias, Servlet servlet, java.util.Dictionary initparams, HttpContext httpContext) throws ServletException, NamespaceException, IllegalArgumentException {
  tempListener.registerServlet(bundle, alias, servlet, initparams, httpContext);
  public void unregister(String alias) throws IllegalArgumentException {
  tempListener.unregister(bundle, alias);
  org.eclipse.equinox/compendium/bundles/org.eclipse.equinox.http/src/org/eclipse/equinox/http/HttpService.java
  service = http.context.registerService(httpsvcClass, this, properties);
  service.unregister();
  protected ResourceRegistration registerResources(Bundle bundle, String alias, String name, HttpContext httpContext) throws NamespaceException {
  { //so one can register at "/"
  protected ServletRegistration registerServlet(Bundle bundle, String alias, Servlet servlet, Dictionary initparams, HttpContext httpContext) throws ServletException, NamespaceException {
  protected void unregister(Bundle bundle, String alias) throws IllegalArgumentException {
  //this is to prevent other bundles from unregistering a bundle's resource/servlet
  org.eclipse.equinox/compendium/bundles/org.eclipse.equinox.http/src/org/eclipse/equinox/http/HttpListener.java

New version. Some inconsistencies between HTTP Service and Jetty in both Felix and Equinox

http://old.nabble.com/HttpServletRequest.getServletPath()-behavior-on-HTTP-Service-does-not-match-Jetty--td30137615.html
http://old.nabble.com/HttpServletRequest.getServletPath()-behavior-on-HTTP-Service-does-not-match-Jetty--td30138030.html

Thank you
Misha

EDIT: Questions asked at (appropriate hopefully) forums:
http://stackoverflow.com/questions/4111684/override-bundle-classloader-in-osgi
http://old.nabble.com/JspRuntimeContext---JspServlet---Using-SpringSource%27s-Jasper-5.5.23-implementation-in-Http-Service--td30146810.html

With changes as follows:
1. Patch from http://tickets.openmrs.org/browse/TRUNK-1851 applied.
2. Re-added jasper in openmrs.bundles (this is not yet relevant at all - i.e., does not make a difference but will...)
3. Used HttpService.registerResources to register /WEB-INF as a valid resource so /WEB-INF/view/index.jsp can map to something
we get farther.

Now opening http://localhost:8080/index.htm results in:

DEBUG - AbstractUrlHandlerMapping.lookupHandler(265) |2010-11-05 19:57:55,183| Matching patterns for request [/index.htm] are [/**/*.htm]
DEBUG - AbstractUrlHandlerMapping.lookupHandler(289) |2010-11-05 19:57:55,194| URI Template variables for request [/index.htm] are {}
DEBUG - AbstractUrlHandlerMapping.getHandlerInternal(220) |2010-11-05 19:57:55,195| Mapping [/index.htm] to handler 'org.springframework.web.servlet.mvc.UrlFilenameViewController@204d080d'
DEBUG - AbstractUrlViewController.handleRequestInternal(96) |2010-11-05 19:57:55,203| Returning view name 'index' for lookup path [/index.htm]
DEBUG - ContentNegotiatingViewResolver.getMediaTypes(271) |2010-11-05 19:57:55,208| Requested media type is 'text/html' (based on filename 'index.htm')
DEBUG - AbstractAutowireCapableBeanFactory.invokeInitMethods(1453) |2010-11-05 19:57:55,216| Invoking afterPropertiesSet() on bean with name 'index'
DEBUG - AbstractBeanFactory.doGetBean(242) |2010-11-05 19:57:55,226| Returning cached instance of singleton bean 'org.springframework.transaction.interceptor.TransactionAttributeSourceAdvisor#0'
DEBUG - ContentNegotiatingViewResolver.resolveViewName(386) |2010-11-05 19:57:55,227| Returning [org.springframework.web.servlet.view.JstlView: name 'index'; URL [/WEB-INF/view/index.jsp]] based on requested media type 'text/html'
DEBUG - InternalResourceView.renderMergedOutputModel(236) |2010-11-05 19:57:55,239| Forwarding to resource [/WEB-INF/view/index.jsp] in InternalResourceView 'index'
WARN - DispatcherServlet.noHandlerFound(962) |2010-11-05 19:57:55,277| No mapping found for HTTP request with URI [/favicon.ico] in DispatcherServlet with name 'servlet_4'

I am tracing this to the following line in:

<link rel="icon" type="image/ico" href="<openmrs:contextPath/><spring:theme code='favicon' />">
webapp/src/main/webapp/WEB-INF/template/headerFull.jsp

There are two features here that could be (and probably are, esp #1 I checked) awry:
1. The TLD for openmrs does not load. Proof:
Adding System.out.println to doStartTag in
./web/src/main/java/org/openmrs/web/taglib/ContextPathTag.java
shows it is not called in OSGi version with HTTP Service.
2. Themes that are found in WEB-INF/classes/themes may not be available on classpath.

Current step is to hack Jasper support into our HTTP-Service using approach so we have bridged support.

This magic is done in some helper util (internal - i.e., not exposed to us) classes in Spring DM:
https://src.springframework.org/svn/spring-osgi/tags/spring-osgi-1.2.1/web/src/main/java/org/springframework/osgi/web/deployer/internal/util/
which basically seem to make a chained classloader for all the TLDs (after making these into fake JARs).

Current step is to figure out exactly how these classloaders link to us, and JspService. i.e., JspService is called when index.htm is retrieved from the version that uses Spring Web Extender (not able to "proxy" from an external server via a deployed WAR file):

DEBUG - ContentNegotiatingViewResolver.resolveViewName(386) |2010-11-05 18:06:37,132| Returning [org.springframework.web.servlet.view.JstlVi\
ew: name 'index'; URL [/WEB-INF/view/index.jsp]] based on requested media type 'text/html'
DEBUG - InternalResourceView.renderMergedOutputModel(236) |2010-11-05 18:06:37,136| Forwarding to resource [/WEB-INF/view/index.jsp] in Inte\
rnalResourceView 'index'
DEBUG - JspServlet.service(248) |2010-11-05 18:06:37,136| JspEngine --> /WEB-INF/view/index.jsp
DEBUG - JspServlet.service(249) |2010-11-05 18:06:37,136| ServletPath: /WEB-INF/view/index.jsp
DEBUG - JspServlet.service(250) |2010-11-05 18:06:37,137| PathInfo: null
DEBUG - JspServlet.service(251) |2010-11-05 18:06:37,137| RealPath: /tmp/jetty-openmrs3852173793073389964.osgi/WEB-INF/view/in\
dex.jsp
DEBUG - JspServlet.service(252) |2010-11-05 18:06:37,137| RequestURI: /openmrs/WEB-INF/view/index.jsp
DEBUG - JspServlet.service(253) |2010-11-05 18:06:37,138| QueryString: null
DEBUG - JspServlet.service(254) |2010-11-05 18:06:37,138| Request Params:

but not at all from our current implementation.

I am not 100% sure how classloaders are related to JspServlet (where does JspServlet enter the picture, if we are chaining bundle classloaders?). Still investigating, as always any helpful hints appreciated...

Yours
Misha

Some JSP progress:
https://bugs.eclipse.org/bugs/show_bug.cgi?id=329706

Working on whether or not we can also use Equinox's JSP support in Apache Felix HTTP Service (it only works in org.eclipse.equinox.http.jetty or org.eclipse.equinox.http.servletbridge, not in org.eclipse.equinox.http as we need Servlet 2.4 API support:
http://www.eclipse.org/equinox/server/jsp_support.php
"Additional Notes: ... The JSP Support requires an HTTP Service that provides support for the Servlet 2.4 API."
This link was also helpful:
http://dev.nepomuk.semanticdesktop.org/wiki/JspPagesInOsgi
Both, unfortunately, are somewhat outdated.

It seems that Equinox HTTP Service HEAD might even have filter support:
https://bugs.eclipse.org/bugs/show_bug.cgi?id=128068#c18
but Equinox is not very Maven-friendly for HEAD builds...

Misha

p.s. Fyi, I believe I made some edits previously because I realized that favicon.ico is actually being loaded by Felix HTTP Service and has nothing to do with JSPs (e.g., it looks for this file even on a fake URL that does not load any JSPs). Thus, I have taken a step back to see how we can use JSP support with HTTP Service.

Update: It looks like we could do something like this project
http://svn.apache.org/repos/asf/directory/studio/trunk/
with a repository module (that contains all the ncessary Equinox jars ) to use Equinox JARs that we might
need.

However, big caveat is we would have to include jar files in SVN repo like we did with ant.

BIG POINTS:

• If we want to use servlet bridge, we have to use Equinox HTTP Service
• If we use Equinox, we have at least one package which cannot be compiled via Maven at all (org.eclipse.equinox.http.helper) and is present, to my knowledge, only on the wso2.org Maven repository (???)
• The big caveat is that, to my knowledge the Equinox Servlet bridge cannot be compiled from within Maven...
  There is a resource here:
  http://mvnrepository.com/artifact/org.eclipse.equinox/servletbridge
  http://mirrors.ibiblio.org/pub/mirrors/maven2/org/eclipse/equinox/servletbridge/1.0.0-v20070523/servletbridge-1.0.0-v20070523.jar
  that seems to be (some form) of exploded WAR. If anyone can help me understand it, much appreciated... i.e., how do we make it work from within Maven? Thx

—

http://www.mail-archive.com/dev@felix.apache.org/msg19852.html

Ok guys, looks like Apache Felix HTTP Service is no go. If we want to use a servlet bridge we have to go with Equinox.

Advantages:

• it seems to be the reference implementation for OSGi specs and is well developed

Disadvantages:

• Felix HTTP Service has Filters; we have to hack with Equinox
• Felix is more Maven-friendly; Equinox is not

Testing:

Note:
To work around
http://www.mail-archive.com/dev@felix.apache.org/msg19851.html
I have made a very small change to the Equinox JSP example
http://prdownloads.sourceforge.net/sse-examples/org.eclipse.equinox.jsp.examples-proj.zip?download
In org.eclipse.equinox.jsp.examples.Activator I changed:
HttpContext commonContext = new BundleEntryHttpContext(context.getBundle(), "/web"); //$NON-NLS-1$
httpService.registerResources("/jsp-examples", "/", commonContext); //$NON-NLS-1$ //$NON-NLS-2$
to read:
HttpContext commonContext = new BundleEntryHttpContext(context.getBundle(), "/"); //$NON-NLS-1$
httpService.registerResources("/jsp-examples", "/web", commonContext); //$NON-NLS-1$ //$NON-NLS-2$
It still works in Equinox, but not in Felix.

– EQUINOX

cd /tmp
rm -rf equinox > /dev/null 2>&1
mkdir equinox
cd equinox
wget http://www.eclipse.org/equinox/server/downloads/bridge.war
jar xvf bridge.war
cd WEB-INF/eclipse/plugins
rm registry
wget http://repository.springsource.com/ivy/bundles/external/javax.el/com.springsource.javax.el/1.0.0/com.springsource.javax.el-1.0.0.jar
wget http://repository.springsource.com/ivy/bundles/external/javax.servlet/com.springsource.javax.servlet.jsp/2.1.0/com.springsource.javax.servlet.jsp-2.1.0.jar
wget http://repository.springsource.com/ivy/bundles/external/javax.servlet/com.springsource.javax.servlet.jsp.jstl/1.1.2/com.springsource.javax.servlet.jsp.jstl-1.1.2.jar
wget http://repository.springsource.com/ivy/bundles/external/org.apache.commons/com.springsource.org.apache.commons.el/1.0.0/com.springsource.org.apache.commons.el-1.0.0.jar
wget http://repository.springsource.com/ivy/bundles/external/org.apache.commons/com.springsource.org.apache.commons.logging/1.0.4/com.springsource.org.apache.commons.logging-1.0.4.jar
wget http://repository.springsource.com/ivy/bundles/external/org.apache.taglibs/com.springsource.org.apache.taglibs.standard/1.1.2/com.springsource.org.apache.taglibs.standard-1.1.2.jar
wget http://mirrors.ibiblio.org/pub/mirrors/maven2/org/eclipse/equinox/jsp/jasper/1.0.0-v20070607/jasper-1.0.0-v20070607.jar -O org.eclipse.equinox.jsp.jasper_1.0.0.v20070607.jar
wget http://maven.springframework.org/osgi/org/springframework/osgi/jasper.osgi/5.5.23-SNAPSHOT/jasper.osgi-5.5.23-20080229.204604-1.jar -O org.springframework.osgi.jasper.osgi_5.5.23.SNAPSHOT.jar
wget http://dist.wso2.org/maven2/org/eclipse/equinox/org.eclipse.equinox.http.helper/1.0.0/org.eclipse.equinox.http.helper-1.0.0.jar
wget http://tickets.openmrs.org/secure/attachment/34885/org.eclipse.equinox.jsp.examples_1.0.0.jar.bz2 && bunzip2 *.bz2
cp /tmp/org.eclipse.equinox.jsp.examples_1.0.0.jar.bz2 . && bunzip2 *.bz2
cd ../../..
rm ../equinox-bridge.war > /dev/null 2>&1
jar cvMf ../equinox-bridge.war WEB-INF/*

You must deploy into a Web container where you will have console access like Jetty (sorry)

e.g., for Jetty 7 (in your main Jetty folder)
rm webapps/equinox-bridge.war > /dev/null 2>&1
cp /tmp/equinox-bridge.war webapps/
java -jar start.jar

Once you see

osgi>

Type the following commands

start org.eclipse.equinox.jsp.examples
start com.springsource.javax.el
start com.springsource.org.apache.taglibs.standard
start org.springframework.osgi.jasper.osgi
start com.springsource.javax.servlet.jsp.jstl
start com.springsource.org.apache.commons.el
start org.eclipse.osgi.services
start com.springsource.javax.servlet.jsp
start com.springsource.org.apache.commons.logging
start org.eclipse.equinox.http.helper

Now run

ss

and make sure all bundles are ACTIVE except org.eclipse.equinox.servletbridge.extensionbundle which is a fragment and cannot be started.

Finally, open a Web browser to:
http://localhost:8080/equinox-bridge/jsp-examples/index.html

and try the examples. They should all work.

– FELIX

cd /tmp
rm -rf felix > /dev/null 2>&1
mkdir felix
cd felix
svn checkout http://svn.apache.org/repos/asf/felix/releases/org.apache.felix.http-2.0.4 -q
cd org.apache.felix.http-2.0.4
mvn clean install -DskipTests
mkdir tmp
cp samples/bridge/target/org.apache.felix.http.samples.bridge-2.0.4.war tmp
cd tmp
jar xvf org.apache.felix.http.samples.bridge-2.0.4.war
sed -i "s/javax.servlet;javax.servlet.http;version=2.5/javax.servlet;javax.servlet.http;javax.servlet.resources;version=2.5/" WEB-INF/framework.properties
cd WEB-INF/bundles
wget http://repository.springsource.com/ivy/bundles/external/javax.el/com.springsource.javax.el/1.0.0/com.springsource.javax.el-1.0.0.jar
wget http://repository.springsource.com/ivy/bundles/external/javax.servlet/com.springsource.javax.servlet.jsp/2.1.0/com.springsource.javax.servlet.jsp-2.1.0.jar
wget http://repository.springsource.com/ivy/bundles/external/javax.servlet/com.springsource.javax.servlet.jsp.jstl/1.1.2/com.springsource.javax.servlet.jsp.jstl-1.1.2.jar
wget http://repository.springsource.com/ivy/bundles/external/org.apache.commons/com.springsource.org.apache.commons.el/1.0.0/com.springsource.org.apache.commons.el-1.0.0.jar
wget http://repository.springsource.com/ivy/bundles/external/org.apache.commons/com.springsource.org.apache.commons.logging/1.0.4/com.springsource.org.apache.commons.logging-1.0.4.jar
wget http://repository.springsource.com/ivy/bundles/external/org.apache.taglibs/com.springsource.org.apache.taglibs.standard/1.1.2/com.springsource.org.apache.taglibs.standard-1.1.2.jar
wget http://mirrors.ibiblio.org/pub/mirrors/maven2/org/eclipse/equinox/jsp/jasper/1.0.0-v20070607/jasper-1.0.0-v20070607.jar -O org.eclipse.equinox.jsp.jasper_1.0.0.v20070607.jar
wget http://maven.springframework.org/osgi/org/springframework/osgi/jasper.osgi/5.5.23-SNAPSHOT/jasper.osgi-5.5.23-20080229.204604-1.jar -O org.springframework.osgi.jasper.osgi_5.5.23.SNAPSHOT.jar
wget http://dist.wso2.org/maven2/org/eclipse/equinox/org.eclipse.equinox.http.helper/1.0.0/org.eclipse.equinox.http.helper-1.0.0.jar
wget http://tickets.openmrs.org/secure/attachment/34885/org.eclipse.equinox.jsp.examples_1.0.0.jar.bz2 && bunzip2 *.bz2
cd ../..
rm ../../felix-bridge.war > /dev/null 2>&1
jar cvMf ../../felix-bridge.war *

Now deploy into Web container. Console is not necessary (or rather doesn't help ):

e.g., for Jetty 7 (in your main Jetty folder)
rm webapps/felix-bridge.war > /dev/null 2>&1
cp /tmp/felix/felix-bridge.war webapps/
java -jar start.jar

Finally, open a Web browser to:
http://localhost:8080/felix-bridge/jsp-examples/index.html

and try the examples. You will see that even on the very first one:
http://localhost:8080/felix-bridge/jsp-examples/jsp2/el/basic-arithmetic.jsp
the very first result:
${1}
does not get properly evaluated...

Misha

Next step:
ERROR - Listener.contextInitialized(154) |2010-11-09 21:10:03,051| Got exception while starting up:
java.lang.NullPointerException
at org.openmrs.osgi.ServletContextWrapper.getRealPath(ServletContextWrapper.java:441)

EDIT: This seems to be related to OpenmrsFilter. I've added but the doFilter method seems to not be called Need to figure out...

JSP support added, and seems to work correctly!

New problem after running:
./run
(mvn clean install -P osgi && cd osgi && ./run)
script to compile and then run OSGi OpenMRS, then waiting for

INFO - FrameworkServlet.initServletBean(320) |2010-11-10 20:59:37,339| FrameworkServlet 'org.openmrs.osgi.ServletAdapter': initialization completed in 53 ms

and finally going to, in a browser:

http://localhost:8080/index.htm

ERROR - HtmlIncludeTag.getInitialRequestUniqueId(164) |2010-11-10 21:00:08,662| Could not find value for _INIT_REQ_UNIQUE_ID_ in pageContext
ERROR - HtmlIncludeTag.getInitialRequestUniqueId(164) |2010-11-10 21:00:08,666| Could not find value for _INIT_REQ_UNIQUE_ID_ in pageContext
ERROR - HtmlIncludeTag.getInitialRequestUniqueId(164) |2010-11-10 21:00:08,667| Could not find value for _INIT_REQ_UNIQUE_ID_ in pageContext
ERROR - HtmlIncludeTag.getInitialRequestUniqueId(164) |2010-11-10 21:00:08,781| Could not find value for _INIT_REQ_UNIQUE_ID_ in pageContext
ERROR - HtmlIncludeTag.getInitialRequestUniqueId(164) |2010-11-10 21:00:08,782| Could not find value for _INIT_REQ_UNIQUE_ID_ in pageContext
ERROR - HtmlIncludeTag.getInitialRequestUniqueId(164) |2010-11-10 21:00:08,783| Could not find value for _INIT_REQ_UNIQUE_ID_ in pageContext
ERROR - HtmlIncludeTag.getInitialRequestUniqueId(164) |2010-11-10 21:00:08,791| Could not find value for _INIT_REQ_UNIQUE_ID_ in pageContext
ERROR - HtmlIncludeTag.getInitialRequestUniqueId(164) |2010-11-10 21:00:08,793| Could not find value for _INIT_REQ_UNIQUE_ID_ in pageContext
ERROR - HtmlIncludeTag.getInitialRequestUniqueId(164) |2010-11-10 21:00:08,794| Could not find value for _INIT_REQ_UNIQUE_ID_ in pageContext
t
ERROR - errorhandler_jsp._jspService(61) |2010-11-10 21:00:09,595| Error on page /WEB-INF/errorhandler.jsp
org.openmrs.api.APIException: A user context must first be passed to setUserContext()...use Context.openSession() (and closeSession() to prevent memory leaks!) before using the API
at org.openmrs.api.context.Context.getUserContext(Context.java:241)
at org.openmrs.api.context.Context.getAuthenticatedUser(Context.java:626)
at org.openmrs.web.taglib.AuthTag.doStartTag(AuthTag.java:29)
at org.apache.jsp.view.index_jsp._jspx_meth_openmrs_005fauthentication_005f0(index_jsp.java:2102)
at org.apache.jsp.view.index_jsp._jspService(index_jsp.java:464)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:328)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:315)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.eclipse.equinox.jsp.jasper.JspServlet.service(JspServlet.java:107)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.eclipse.equinox.http.helper.ContextPathServletAdaptor.service(ContextPathServletAdaptor.java:36)
at org.eclipse.equinox.http.servlet.internal.ServletRegistration.service(ServletRegistration.java:61)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.processAlias(ProxyServlet.java:126)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.service(ProxyServlet.java:68)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.eclipse.equinox.http.jetty.internal.HttpServerManager$InternalHttpServiceServlet.service(HttpServerManager.java:269)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:428)
at org.mortbay.jetty.servlet.ServletHandler.dispatch(ServletHandler.java:677)
at org.mortbay.jetty.servlet.Dispatcher.dispatch(Dispatcher.java:289)
at org.mortbay.jetty.servlet.Dispatcher.forward(Dispatcher.java:171)
at org.eclipse.equinox.http.servlet.internal.RequestDispatcherAdaptor.forward(RequestDispatcherAdaptor.java:30)
at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:250)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1060)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:798)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:716)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:549)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.openmrs.osgi.ServletAdapter.service(ServletAdapter.java:25)
at org.eclipse.equinox.http.servlet.internal.ServletRegistration.service(ServletRegistration.java:61)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.processAlias(ProxyServlet.java:126)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.service(ProxyServlet.java:76)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.eclipse.equinox.http.jetty.internal.HttpServerManager$InternalHttpServiceServlet.service(HttpServerManager.java:269)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:428)
at org.mortbay.jetty.servlet.ServletHandler.dispatch(ServletHandler.java:677)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:568)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1530)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1482)
at org.mortbay.http.HttpServer.service(HttpServer.java:909)
at org.mortbay.http.HttpConnection.service(HttpConnection.java:820)
at org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:986)
at org.mortbay.http.HttpConnection.handle(HttpConnection.java:837)
at org.mortbay.http.SocketListener.handleConnection(SocketListener.java:245)
at org.mortbay.util.ThreadedServer.handle(ThreadedServer.java:357)
at org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java:534)

UPDATE: Fixed. Now working on multiple alias support for same servlet. This does not exist on OSGi unfortunately

EDIT: It actually seems to just be relative URLs...

<c:import url="http://rss.slashdot.org/Slashdot/slashdot"/>

works great!

Update: I have been having a lot of difficulty making the JSTL (e.g., c:import tag) work using the Equinox JSP implementation with Spring Web Extender in the to-be-embedded-in-servlet version of OSGi'ed OpenMRS.

Just wanted to post a brief update.

Please find attached the relevant patch in
1596-latest-equinox-http-service-work-in-progress-trying-to-make-c-import-work.patch

The osgi-extra.tar.bz2 file contains the binary eclipse jars necessary for this in osgi/extra (they will be uncompressed there automatically by:
tar xvjf osgi-extra.tar.bz2)

To run, apply the patch, uncompress binary JARs using tar xvjf osgi-extra.tar.bz2, then use the ./run shell script added in the OpenMRS trunk directory.

Unfortunately, the c:import statement I have added to src/main/webapp/WEB-INF/view/index.jsp fails to load login.jsp. I believe this might be the underlying reasons the openmrs:portlet tag is not working either

Thus, no login page

For reference, eclipse-plugins-works.tar.bz2 works marvelously. This is using basic examples from:
http://www.eclipse.org/equinox/server/jsp_support.php

Misha

I will hack on this. I think it is more feasible to embed OSGi in a war and add support for new modules instead of migrating the whole app at once.

Rafał Korytkowski I've been looking into runtime plugin frameworks for OpenBoxes and just found the Atlassian plugin framework yesterday. Not sure it will do exactly what we want, but worth a look.
https://developer.atlassian.com/display/PLUGINFRAMEWORK/Embedding+the+Plugin+Framework

Justin, it's exactly what I was thinking about. I will speak to guys from Atlassian by the end of this month (they are based in Gdansk).

I am really interested in migration of OpenMRS to OSGi framework. I have been studying OSGi frameworks and have also work on basic tutorial and have knowledge of it how the bundles works and it advantages. I want to start working on this task of migration as this is a real implementation of OSGi for me till now I just have been working on tutorials. I have read some previous comments and seen patches submitted. I have started working on it as my project for Google Summer of Code 2013.

Filip Spiridonov are you still working on thia?

I do not think so.

After understanding how OSGi and OpenMRS works, I think there is no easy way to marry them

The problem is that in OpenMRS module can access and change almost anything in the system.

In OSGi, the module is isolated from others. Every module has it's own spring context and the only way modules communicate to each other is by publishing/importing services to/from the Service Registry. As a result, in order to make OpenMRS OSGi-friendly, every place that can be changed by a module should be rewritten using OSGi services (Service Registry). This would require significantly rewriting openmrs core, and will affect the rest of the modules. Moreover, you will need a deep understanding of the current openmrs architecture.

I would be glad to give any OSGi-related advice or to answer any questions.