Re: [osgi-dev] Blacklisting bundle versions

[Michael Lipp <mnl@xxxxxx>]

Considering the info about you on LinkedIn, there must be something non-obvious about this question.

Let me provide a beginner's answer to check if I got it right. There are actually two occasions during development when you might want to blacklist bundles: during build time and at run-time.

In both situations, the bundles available for building (or running) are primarily controlled by the configuration of the repository/repositories used (https://mnlipp.github.io/osgi-getting-started/Repositories.html). When using bnd to provide the "classpath" for building, the configuration of the "built-in" repository providers follows a "list of positives" approach, i.e. you explicitly specify the bundles that should be available in your repositories (no blacklisting required). The "Bnd POM Repository" (https://bnd.bndtools.org/plugins/pomrepo.html) deviates from this approach a bit, because it automatically provides additional bundles as specified by the dependencies from the Maven POM. AFAIK there is no possibility to blacklist individual dependencies with this plugin. (But on the other hand side, if you cannot rely on the defined maven dependencies, something's wrong anyway.)

My "Indexed Maven Repository plugin" (http://mnlipp.github.io/de.mnl.osgi/IndexedMavenRepository.html) takes the opposite approach by making everything from a maven group available unless explicitly disabled (effectively blacklisted). This approach should not be taken in an enterprise context (see below), but is very convenient for small projects that simply assume newer versions to be better.

At run-time, there may be two different scenarios. The easy one is that you resolve all dependencies at build time using a bndrun configuration. There you can explicitly blacklist specific versions to prevent them from being used when resolving your initial (explicitly required) bundles. I assume that you have seen this before, but here (https://github.com/mnlipp/jgrapes-osgi/blob/master/org.jgrapes.osgi.demo.console/democonsole.bndrun) is a non-trivial bndrun file. The list of runbundles is what results from the automatic resolution, considering whatever your repositories provide as candidate (unless blacklisted).

The more complicated run-time situation is when you have something like e.g. Eclipse that does its resolution on startup. Here you have to look at the mechanism used and find out how to configure it to blacklist something (if possible).

While all this may seem a bit complicated, the reasoning behind it is OSGi's approach of separating API and implementation (it's not unique to OSGi, but followed rather strictly in this context). So the repository used during building should only provide the API-bundles used by your bundle (or application) under development and every change of an API's version should be a controlled by an explicit process. The actual implementation of the API used at run-time is much more dynamic. Either because you want to try another provider (e.g. switching from Felix to Equinox) or because some version of an implementation bundle has proven to be buggy and you want to replace it with the fixed version (and optionally blacklist the buggy version to make sure that it isn't used under any circumstances).

 - Michael

Am 09.10.24 um 12:08 schrieb Dr. James J. Hunt via osgi-dev:

Dear Colleagues,

Does OSGi provide any mechanism for blacklisting particular versions of OSGi bundles?

Sincerely,

James

Dr. James J. Hunt
CEO & CTO


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