I think we should rather focus on the subsystem spec. Perhaps we could
already implement the spec like it is now and do what we think is best
where the spec is lacking. Then when the spec is finished we could
adjust our code to be fully spec compliant. So we would not have to
implement two things that do quite the same thing.
Christian
Am 13.11.2011 00:49, schrieb David Jencks:
There's been a lot of discussion about isolation in osgi, including "region" based
isolation in virgo, composite bundle support in some versions of equinox, and a lot of work on the
subsystems spec. Isolation in virgo and the aries subsystem RI appears to be going to be based on
a "region" jar in equinox that glyn wrote for virgo.
The subsystems spec looks like it's going to provide a very convenient way of
setting up some kinds of isolation, but the plain regions jar while harder to
configure allows a lot more flexibility. Also the subsystems spec won't be
ready for a while and the RI is certainly lagging behind the spec drafts. I
think it would be useful right now to have a direct region-based isolation
solution for karaf, and it might be useful to preserve the additional
flexibility even when subsystems are available.
I've implemented a basic regions integration for karaf (trunk). See
https://issues.apache.org/jira/browse/KARAF-1009
Some features:
- regions are configured in etc/regions-config.xml. This is installed on first
startup, changes are ignored unless you do a clean start
- admin commands including region:info that shows the regions, filters, and
which bundles are in which region. There are some more commands described in
the jira but they are basically useful only for playing around.
- features get a new "region" attribute making them install into the specified
region
- Aries RecursiveBundleTracker has been modified to work with R43 hook based
isolation (that's what the region jar uses under the covers) so the aries
blueprint extender (and other extenders using the RecursiveBundleTracker) will
work on bundles in isolated regions.
There's more description in the jira.
As an example, I've configured the jpa and jndi features to go in the
application region configured in regions-config.xml. The jpa feature has a
blueprint plan and if you have up to date aries bundles you should see that the
blueprint stuff is created properly.
These console commands might be interesting to try:
region:info
bundle:list -t 0
feature:install jpa
bundle:list -t 0
region:info
feature:install jndi
bundle:list -t 0
region:info
I'd really appreciate some feedback on this. I know the admin commands are
pretty rudimentary :-)
I also know it would be pretty nice to be able to change filters once created.
As far as I can tell so far the regions jar doesn't let you do this, and
although I think that ability will be needed for subsystems I don't propose to
implement it yet.
Is this something we want in karaf?
thanks
david jencks
--
Christian Schneider
http://www.liquid-reality.de
Open Source Architect
Talend Application Integration Division http://www.talend.com
