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Manipulating MANIFEST headers while deploying bundles through a PLAN file [message #642613]

Thu, 02 December 2010 01:01

Amit Kumar

Messages: 3
Registered: December 2010

Junior Member

Use Case :

Add a custom Tomcat Valve implementation in tomcat-server.xml. The valve can function as the user-principal initializer if there is a given request header set (OAM cookie) or can provide any other custom implementation.

I have a bundle library created for implementing the required feature. The implemented Valve depends on Tomcat APIs (Catalina libraries). I have copied my JAR under $SERVER_HOME/repository/ext.

Now, when I try to configure this valve in $SERVER_HOME/config/tomcat-server.xml, the DM server fails to start due to missing classes (My Valve in this case).

So, I needed to tell Spring DM extender to somehow load my classes when loading bundle com.springsource.osgi.webcontainer.tomcat, it should also load my bundle. In dependencies terms, it simply means, I have to modify the MANIFEST of bundle com.springsource.osgi.webcontainer.tomcat and add my JAR/Package to 'Import-Bundle' or 'Import-Package' header.

Fortunately, com.springsource.osgi.webcontainer.tomcat bundle is deployed using the PLAN file under repository/ext,
named com.springsource.server.web-2.0.0.RELEASE.plan, and I can manipulate the bundle manifest headers using following syntax in the PLAN -

<artifact type="bundle" name="com.springsource.osgi.webcontainer.tomcat" version="[1, 2)">
<property name="header:Import-Bundle" value="oam.plugins.tomcat;version=1.0.0"/>
</artifact>

Things work perfectly for me at this point without touching the com.springsource.osgi.webcontainer.tomcat bundle. However, this overwrites the existing Import-Bundle headers in com.springsource.osgi.webcontainer.tomcat if any during deploy.

Question:

Is there a way I can append my bundle to the 'Import-Bundle' header through similar configuration. I wish there was a feature to support this 'concatination' behavior for Manifest headers through the <property> attribute in the PLAN. I am not aware if there is already a feature currently supported for this.

I would appreciate any comments with respect to this.

[Updated on: Thu, 02 December 2010 01:40]

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Re: Manipulating MANIFEST headers while deploying bundles through a PLAN file [message #642928 is a reply to message #642613]

Fri, 03 December 2010 11:38

Glyn Normington

Messages: 1222
Registered: July 2009

Senior Member

There is no support for, or enhancement bugzilla to add, that kind of append mechanism. I'm not sure what it would take to implement - could be pretty expensive if it involved a core Spring change.

There are a couple of alternatives though. Firstly, the Tomcat bundles will never use Import-Bundle as we avoid making their manifests Virgo specific, so you may simply continue to add an Import-Bundle header. Secondly, if you don't like this, you could create a fragment to attach to the Tomcat bundle which would specify either Import-Bundle or Import-Package in the fragment's manifest.

Hope that helps.

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Re: Manipulating MANIFEST headers while deploying bundles through a PLAN file [message #643040 is a reply to message #642928]

Fri, 03 December 2010 17:52

Amit Kumar

Messages: 3
Registered: December 2010

Junior Member

Thank you for your response Glyn. I was not aware that a Fragment would let me manipulate any/all of the host bundle MANIFEST. Also, this approach requires more work and a little complex than the first one. So, for the time being I will continue with my first approach.

On the other hand, I was hoping that, it was not very difficult to support the 'concatinate' behavior for MANIFEST headers during bundle deployment.

Following is the code fragment I was targeting, which could be a possible place for implementing this feature -

Bundle : com.springsource.kernel.deployer-2.x.x.RELEASE.jar
Package : com.springsource.kernel.deployer.core.internal
Class : BundleDeploymentPropertiesTransformer.java
Method : doTransformBundleArtifact()
Code Fragment: manifest.setHeader(headerName, ...)

I may not be aware of the other complexities involved in supporting this feature, so might be off the track here.

[Updated on: Fri, 03 December 2010 17:54]

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Re: Manipulating MANIFEST headers while deploying bundles through a PLAN file [message #643292 is a reply to message #643040]

Mon, 06 December 2010 12:09

Glyn Normington

Messages: 1222
Registered: July 2009

Senior Member

Thanks for investigating. I was not familiar with that piece of code. Please would you raise an enhancement bugzilla as the implementation now seems tractable.

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