Thursday, November 25, 2010

How to develop with the Virgo Kernel in Eclipse

A number of groups are discovering that the Virgo Kernel is a really useful OSGi runtime. For instance the Rich Ajax Platform project have documented how to run RAP on the kernel.

Others have steered clear of the kernel because the Eclipse-based Virgo tooling does not support the kernel directly (see bug 331101). However, it's really easy to get the tooling working with the kernel. Here's how...

First, set up the Virgo tooling in Eclipse as described in the Tooling chapter of the Virgo Programmer Guide.

However, when you create a new Virgo Web Server server runtime environment and point at a Virgo kernel installation, you'll see the following error:

.version file in lib directory is missing key 'virgo.server.version'. Make
sure to point to a Virgo Server installation.

Edit lib/.version in the kernel installation to contain the key 'virgo.server.version' instead of 'virgo.kernel.version'. Then the above error goes away and you can continue to set up the runtime environment and server as per the instructions in the Programmer Guide.

You can then use the Virgo tooling to do all the usual things: start and stop the kernel, create and deploy bundles, PARs and plans, examine bundles, and explore package and service wirings.

Thursday, November 11, 2010

OSGi Adoption Experience

The Mule team have blogged about their decision not to adopt OSGi. The decision seems reasonable: OSGi isn't a panacea and I guess the benefits didn't outweigh the costs in their case.

One of their number, Ross Mason, correctly identifies some of the costs of adopting OSGi. He would like OSGi to be almost completely invisible to the developer, leaving him or her free to define an application in terms of modules without dealing directly with manifests, bundles, and build systems. The somewhat messy details of developing and building modular applications with OSGi are partly what led SpringSource to donate the dm Server project to Eclipse as Virgo. The aim is to grow the user community and smooth out the wrinkles in the developer experience.

Adoption is going pretty well. Virgo recently shipped its first release. SAP are adopting Virgo in a strategic way. VMware products in development are using dm Server/Virgo to obtain the benefits of modular application code. Others are using dm Server/Virgo to host substantial applications in sectors including investment banking, networking, healthcare, online gaming, and academic research.

As we prepare to donate the Virgo tooling to Eclipse and collaborate in the OSGi Enterprise Tools project inside Eclipse with the likes of SAP, EclipseSource, and Eteration, I'm optimistic about improving the developer experience.

Dissenting voices such as those of the Mule team are a good reality check. Efforts, such as Mule, to try to find intermediate modularity solutions with some of the benefits of OSGi but with smaller costs should also help by providing data points for comparison with full blown OSGi adoption.

I'm looking forward to more experience reports from application development groups that have adopted OSGi or technologies like Mule so others can make a more informed decision about the technology to adopt. Certainly OSGi users are starting to publish their experience. Perhaps users of Mule will soon do the same.

Monday, November 01, 2010

Eclipse Virgo 2.1.0 Release

Jump to Hyperspace
Jump to Hyperspace, courtesy of Steve Jurvetson
Eclipse Virgo has shipped its first release after several months of work to contribute it to Eclipse.

The majority of the effort was to make the contribution acceptable from an Eclipse legal perspective. There were some close shaves, like when a file (mime.types) in the Spring Framework turned out to have a restrictive license. The file would have been virtually impossible to recreate from scratch. I am very grateful to the original author, Ian Graham, for solving this problem by making the content available under an Apache license. I would also like to thank Barb Cochrane and Sharon Corbett of the Eclipse legal team who cheerfully and efficiently handled over 200 "contribution questionnaires" covering the code donated to Virgo and its dependencies.

Apart from that, we have repackaged the code in the org.eclipse namespace, speeded up the startup considerably, upgraded several dependencies, fixed a few bugs, and made several enhancements.

The response from the community was particularly encouraging with thousands of downloads of the milestones and numerous forum posts and mailing list discussions. We are particularly grateful to the code contributors, listed in the release notes.

The main objective of contributing Virgo was to grow the community and thereby make the technology more easily consumed by application developers. The project seems to be meeting the community objective and we are now preparing to donate the Virgo tooling to Eclipse which will enable the community to help us make the developer experience smoother, especially for newcomers to modularity and OSGi.

Finally, I'd like to thank the other Virgo committers, Chris Frost and Steve Powell, for their persistence and thoroughness. I'm glad we can now move on to more interesting items for the next release. Thanks too to everyone else in SpringSource who supported the Virgo project in various ways. We couldn't have done it without you.

The future looks promising, starting with a Virgo face to face meeting at the end of this month. It's not too late to express your interest (on virgo-dev) if you would like to attend.


OSGi (130) Virgo (59) Eclipse (10) Equinox (9) dm Server (8) Felix (4) WebSphere (3) Aries (2) GlassFish (2) JBoss (1) Newton (1) WebLogic (1)