Monday, September 06, 2010

RemoteOBR

Over the last months, I’ve been pondering over the use of OBR, the OSGi Bundle Repository. OBR describes resources (mostly OSGi bundles) in terms of capabilities and requirements. The OBR resolver is able to find the list of bundles needed to fulfill a given bundle requirements. This allows deploying a bundle and its required dependencies without caring too much about the exact dependencies being deployed. In addition, it takes into account the already locally installed bundles and thus reduces unneeded duplication of libraries in different versions.

When I started to use the Felix OBR repository earlier this year, I quickly ran into performance problems during both the parsing phase and the resolution phase. It was nearly unusable for repositories more than a few dozens of resources, which mean in real world scenarii. So I spent some time optimizing things a bit. I also enhanced the API to provide more meaningful informations and to allow more control over the resolution. That work has been released as part of the 1.6.x series of Felix BundleRepository.

One of the enhancement I made was the ability to have a more powerful query mechanism for resources. The goal was to be able to actually use OBR to help people find needed OSGi bundles. This is often one of the main problem people have when building OSGi applications in the integration space. The SpringSource guys have done a good job at providing their Enterprise Bundle Repository and Apache ServiceMix also regularly provide a bunch of OSGi bundles for third party libraries

The main problem with those repositories is that they tend to become huge (more than 7 Mb of xml), which means it takes a long time to download, parse and consumes a lot of memory once it has been parsed. If you use it on multiple JVMs, it becomes quickly a problem and a waste.

That’s when I started to think about the idea of a remote OBR repository. So here we are: I’ve created a small project named RemoteOBR at FuseSource Forge. This project decouples the client API from the real repository manager which is remotely queried using a REST protocol.

It’s not complete yet, but it is already usable, so I invite everyone to go the RemoteOBR website, download, try it and provide feedback.

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