ActorRegistry and OSGI
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Mariusz
Jun 9, 2010, 6:26:51 AM6/9/10
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Question to OSGI and Akka experts:
Is it safe to use ActorRegistry in OSGi environment? I am afraid that
in osgi environment there will be many instances of ActorRegistry
because of many class loaders used to access ActorRegistry in
different bundles - is it possible? I don't know how scala handles
singleton objects in OSGi environment.
What solution is better to obtain actor: use ActorRegistry or publish
every actor as osgi service?
Mariusz
Is it safe to use ActorRegistry in OSGi environment? I am afraid that
in osgi environment there will be many instances of ActorRegistry
because of many class loaders used to access ActorRegistry in
different bundles - is it possible? I don't know how scala handles
singleton objects in OSGi environment.
What solution is better to obtain actor: use ActorRegistry or publish
every actor as osgi service?
Mariusz
Heiko Seeberger
Jun 9, 2010, 9:45:33 AM6/9/10
to akka...@googlegroups.com
This is a good question, but I doubt we can answer it today, because the efforts to create OSGi support are not yet finished. First step is to provide bundles and second to investigate all the hidden pitfalls.
--
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Heiko
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Jonas Bonér
Jun 9, 2010, 9:58:53 AM6/9/10
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Right. All I can say now is that we have to and will solve it.
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On 9 Jun 2010 15:45, "Heiko Seeberger" <heiko.s...@googlemail.com> wrote:
This is a good question, but I doubt we can answer it today, because the efforts to create OSGi support are not yet finished. First step is to provide bundles and second to investigate all the hidden pitfalls.
Heiko
On 9 June 2010 12:26, Mariusz <mariu...@gmail.com> wrote:
>
> Question to OSGI and Akka experts:...
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Company: weiglewilczek.com
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Follow me: twitter.com/hseeberger
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Stambecco, highly scalable computing: stambecco.org
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Roman Roelofsen
Jun 10, 2010, 5:20:21 PM6/10/10
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There shouldn't be a problem wrt OSGi. As long as you dont include
Akka in each of your bundles there will be one classloader for Akka
and therefore only one ActorRegistry.
Akka in each of your bundles there will be one classloader for Akka
and therefore only one ActorRegistry.
However, how to apply the OSGi programming model (service registry,
...) is still open for discussion.
Cheers,
Roman
On 9 June 2010 12:26, Mariusz <mariu...@gmail.com> wrote:
> --
juyttenh
Jan 26, 2011, 9:13:42 AM1/26/11
to akka...@googlegroups.com
I've been thinking about this topic as well, as a novice akka user trying out akka in an OSGi environment.
Say I have a bundle containing 2 actors: actor A is intended to be used only internally by the bundle, and actor B would also be available to other bundles. If I understand this correct (and assuming that I don't include akka in each of my bundles) there would be just one ActorRegistry for the entire OSGi environment in which both actors are registered, and as such both would be available to other bundles as well.
I could instead publish only actor B as an OSGi service, and make all my bundles express dependencies using services. But still I can 't prevent any other bundle to directly lookup actor A from the registry, and this way get around my limited set of exported services. If I make actor B use strong-typed messages (case classes) or use a TypedActor and put these in non-exported packages, any other bundle would still be able to get the actor from the registry, but it would be rather useless as the messages it accepts are not available to this bundle. But still, being able to access an actor of another bundle would allow e.g. to stop this actor.
The ActorRegistry allows also to shutdown all actors. If I'd do this in the stop() method of a BundleActivator to shutdown a single bundle, all actors of all bundles would be shutdown. So that's a bit tricky, I guess I could instead accomplish this by using supervisors?
More in general, thinking in terms of modules and bundles it might be useful to have some sort of ActorRegistry for each bundle. Each bundle can decide to publish individual actors as services (or the registry as a whole if really needed).
Just my 2cts.
Anyone developed any opinions on this in the meantime?
Grtz,
Jan
Say I have a bundle containing 2 actors: actor A is intended to be used only internally by the bundle, and actor B would also be available to other bundles. If I understand this correct (and assuming that I don't include akka in each of my bundles) there would be just one ActorRegistry for the entire OSGi environment in which both actors are registered, and as such both would be available to other bundles as well.
I could instead publish only actor B as an OSGi service, and make all my bundles express dependencies using services. But still I can 't prevent any other bundle to directly lookup actor A from the registry, and this way get around my limited set of exported services. If I make actor B use strong-typed messages (case classes) or use a TypedActor and put these in non-exported packages, any other bundle would still be able to get the actor from the registry, but it would be rather useless as the messages it accepts are not available to this bundle. But still, being able to access an actor of another bundle would allow e.g. to stop this actor.
The ActorRegistry allows also to shutdown all actors. If I'd do this in the stop() method of a BundleActivator to shutdown a single bundle, all actors of all bundles would be shutdown. So that's a bit tricky, I guess I could instead accomplish this by using supervisors?
More in general, thinking in terms of modules and bundles it might be useful to have some sort of ActorRegistry for each bundle. Each bundle can decide to publish individual actors as services (or the registry as a whole if really needed).
Just my 2cts.
Anyone developed any opinions on this in the meantime?
Grtz,
Jan
√iktor Klang
Jan 26, 2011, 9:38:48 AM1/26/11
to akka...@googlegroups.com
How about classloader isolation for your different bundles and use remote actors to communicate between bundles?
Just my 2cts.
Anyone developed any opinions on this in the meantime?
Grtz,
Jan
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Robert Wills
Feb 3, 2011, 3:20:47 AM2/3/11
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Just came across this and thought of this thread. Would this be a
possible solution
(at least for Felix)?
http://felix.apache.org/site/apache-felix-framework-launching-and-embedding.html
possible solution
(at least for Felix)?
http://felix.apache.org/site/apache-felix-framework-launching-and-embedding.html
The activator could then make sure that all activated bundles use the
same actor
registry.
I'll have a quick play with trying to get this to work if I get the chance.
-Rob
Jonas Bonér
Feb 3, 2011, 4:12:45 AM2/3/11
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On 3 February 2011 09:20, Robert Wills <wrw...@gmail.com> wrote:
> Just came across this and thought of this thread. Would this be a
> possible solution
> (at least for Felix)?
> http://felix.apache.org/site/apache-felix-framework-launching-and-embedding.html
>
> The activator could then make sure that all activated bundles use the
> same actor
> registry.
>
> I'll have a quick play with trying to get this to work if I get the chance.
> Just came across this and thought of this thread. Would this be a
> possible solution
> (at least for Felix)?
> http://felix.apache.org/site/apache-felix-framework-launching-and-embedding.html
>
> The activator could then make sure that all activated bundles use the
> same actor
> registry.
>
> I'll have a quick play with trying to get this to work if I get the chance.
Great. Thanks. Please let us know what your conclusions are.
--
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Specialist at Large
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blog: http://jonasboner.com
twtr: @jboner
juyttenh
Feb 4, 2011, 4:39:05 AM2/4/11
to Akka User List
I'm not sure if I understand your post correctly, but IMHO it's not
really an issue that all activated bundles should use the same
registry. This is the case as long as you don't include Akka in each
of your bundles (as described earlier). It might become an issue if
you'd deploy two versions of Akka, e.g. when your bundles use
different versions of Akka.
I myself am looking for a way to actually have multiple registries,
one for each bundle. This way I could avoid bundles to access actors
they're not supposed to, as only the actors that are exported as OSGi
services are available to other bundles.
I'm still thinking about what Viktor suggested about classloader
isolation and remote actors. I guess this could indeed be a solution,
although I'm not sure it would be a desirable one. What would be the
impact (e.g. performance?) of using remote actors? This would required
a server (and port) for each bundle?
-Jan
--
Jan Uyttenhove / @xorto <twitter.com/xorto>
www.xume.com & blog.xume.com
On Feb 3, 9:20 am, Robert Wills <wrwi...@gmail.com> wrote:
> Just came across this and thought of this thread. Would this be a
> possible solution
> (at least for Felix)?http://felix.apache.org/site/apache-felix-framework-launching-and-emb...
really an issue that all activated bundles should use the same
registry. This is the case as long as you don't include Akka in each
of your bundles (as described earlier). It might become an issue if
you'd deploy two versions of Akka, e.g. when your bundles use
different versions of Akka.
I myself am looking for a way to actually have multiple registries,
one for each bundle. This way I could avoid bundles to access actors
they're not supposed to, as only the actors that are exported as OSGi
services are available to other bundles.
I'm still thinking about what Viktor suggested about classloader
isolation and remote actors. I guess this could indeed be a solution,
although I'm not sure it would be a desirable one. What would be the
impact (e.g. performance?) of using remote actors? This would required
a server (and port) for each bundle?
-Jan
--
Jan Uyttenhove / @xorto <twitter.com/xorto>
www.xume.com & blog.xume.com
On Feb 3, 9:20 am, Robert Wills <wrwi...@gmail.com> wrote:
> Just came across this and thought of this thread. Would this be a
> possible solution
>
> The activator could then make sure that all activated bundles use the
> same actor
> registry.
>
> I'll have a quick play with trying to get this to work if I get the chance.
>
> -Rob
>
>
>
>
>
>
>
> On Wed, Jan 26, 2011 at 2:38 PM, √iktor Klang <viktor.kl...@gmail.com> wrote:
> The activator could then make sure that all activated bundles use the
> same actor
> registry.
>
> I'll have a quick play with trying to get this to work if I get the chance.
>
> -Rob
>
>
>
>
>
>
>
Akka Team
Feb 4, 2011, 5:38:22 AM2/4/11
to akka...@googlegroups.com
On Fri, Feb 4, 2011 at 10:39 AM, juyttenh <juyt...@gmail.com> wrote:
I'm not sure if I understand your post correctly, but IMHO it's not
really an issue that all activated bundles should use the same
registry. This is the case as long as you don't include Akka in each
of your bundles (as described earlier). It might become an issue if
you'd deploy two versions of Akka, e.g. when your bundles use
different versions of Akka.
I myself am looking for a way to actually have multiple registries,
one for each bundle. This way I could avoid bundles to access actors
they're not supposed to, as only the actors that are exported as OSGi
services are available to other bundles.
I'm still thinking about what Viktor suggested about classloader
isolation and remote actors. I guess this could indeed be a solution,
although I'm not sure it would be a desirable one. What would be the
impact (e.g. performance?) of using remote actors? This would required
a server (and port) for each bundle?
Yes. I'd recommend running one VM per app, for fault-tolerance reasons.
If you want to have one ActorRegistry per app, you either use classloader-isolation or run it in separate VMs.
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