I have also looked into the Remote Services Spec. The problem is that
Remote Services work a bit differently.
At least in current implementations you get a local proxy for each
remote service that is detected. You also have to bind to one of those
services to send to the
respective remote service. So typically in Remote Services you have kind
of a point to point behaviour.
When doing Events you typically want rather publish / subscribe.
Basically many containers subscribe to all the topics they are
interested in and you send the event then only once.
I have no idea how I would create that behaviour with Remote Services.
Btw. the idea for the jms bridge for Events was based on a master thesis
about distributed OSGi. In the thesis a jms bridge for Events was used
to implement the Discovery port of the Remote Service Admin spec.
So in that case it was the other way round. They used remote events over
jms to implement Remote Services. I found the idea to transport Events
over jms very natural so I implemented a similar bridge.
In any case I am open to suggestions. Regarding remote services I just
did not yet understand how I would apply them.
Christian
On 10/12/2012 03:05 PM, Nick Wilson wrote:
Hi Christian,
Have you had a look at the Enterprise OSGi Remote Services specification? I
provides an easy way to publish services (including event handlers) to remote
containers by just adding a few properties to the service.
It sounds like your prototype is doing very similar work, and nothing wrong
with JMS as a transport. Might be worth considering the Remote Services spec.
if you want to expand it beyond just events.
Regards,
Nick
-----Original Message-----
From: Christian Schneider [mailto:[email protected]] On Behalf Of
Christian Schneider
Sent: 12 October 2012 10:00
To: Felix Dev
Subject: Re: EventAdmin jms bridge
Hi all,
I would be happy to get some feedback about my proposed EventAdmin jms bridge.
I am fully aware that is not yet ready for addition but I wanted to get
feedback early in the development.
So what do you think? Is it a good idea to send Events to remote containers? Is
jms the right transport?
.. and of course is felix the right place for such a project?
Best regards
Christian
Am 09.10.2012 15:23, schrieb Christian Schneider:
Hi all,
I have implemented a first prototype of a jms bridge for the
EventAdmin service.
The idea is to be able to transparently send Events between OSGi
containers using a jms provider.
The current status is that events can be published and received and
the jms ConnectionFactory is bound as an OSGi service.
The following is missing:
- Configuration which jms ConnectionFactory to use if there are more
than one
- Configuration of the topic prefix on the jms server
- Configuration of the EventAdmin topics to send / receive as
typically you will not want all to be sent
- Ignoring our own events to avoid loops
If there is interest in the felix community I would like to donate the
bridge.
I have already used the felix project structure and package names to
make it easy to integrate.
The current code can be found here:
https://github.com/cschneider/event-admin-jms
What do you think?
Christian
