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https://issues.apache.org/jira/browse/WHIRR-512?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13206252#comment-13206252
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Ioannis Canellos commented on WHIRR-512:
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Inside an OSGi environment this is already possible. In fact this is already
tested inside the integration tests.
The WhirrServicesTest under platforms/karaf/itests does exactly this:
Inside a vanilla Karaf instance it registers the a descriptor which defines the
artifacts required for running whirr & its services (split in logical groups:
whirr, whirr-zookeeper, whirr-hadoop etc). Then it installs to the container
one by one and makes sure that whirr can discover and use any of the services.
This can be applied to any OSGi environment and not just Karaf.
Now, lets think outside OSGi. There are two things needed. The first is
dependency resolution and the second is dynamic registration.
Dependency resolution: Even with the use of a tool like Aether or Ivy (I am
only a bit familiar with the first) no one can guarantee that the resolution
will succeed as it will require that the maven metadata reflect 100% the
runtime requirements (its not always the case) and of course that can't prevent
conflicts (maybe isolation will help here).
Dynamic Registration: Yes dropping jars to the lib will work and its a fine
approach when you are dealing with the CLI. You can even add some commands for
adding new services by referencing a descriptor or something. If we are talking
about whirr as a library, which is going to be used inside a java application,
container etc, then it gets a bit more complicated. I think that the SPI
approach will have issues if the class is not in the class loader hierarchy and
that could be a problem if you are loading services isolated. Maybe commons
discovery & some TCCL can do the trick.
This is exactly why I love OSGi.
> Add Service Repository
> ----------------------
>
> Key: WHIRR-512
> URL: https://issues.apache.org/jira/browse/WHIRR-512
> Project: Whirr
> Issue Type: Improvement
> Reporter: Grant Ingersoll
> Priority: Minor
>
> Perhaps instead of constantly adding services to Whirr, we should simply have
> a mechanism that allows people to publish them to a repository (such as
> Maven's repo -- note, this doesn't require people to use maven, but it does
> provide a place to publish) and then in Whirr, you can just say "go get this
> service from this repository" instead of the project itself constantly adding
> services and maintaining more and more "one-off" services code.
> Not sure if this is a dupe, but a quick search didn't reveal it.
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