I've created https://issues.apache.org/activemq/browse/CAMEL-2693 for that.
On Thu, Apr 29, 2010 at 14:06, Bengt Rodehav <be...@rodehav.com> wrote:
> Hello Willem,
>
> Yeah, I guess it could potentially be a lot of service dependencies.
> Remember though that these dependencies are present regardless if we
> handle them or not. If I have routes referring to 10 components, then
> these components MUST be registered before I create my routes. Right?
>
> Today, there is no way of being informed when necessary registrations
> have been done in Camel. This means that one has to make sure, by
> other means, that every bundle that could potentially contain a
> required camel component must be resolved and started before trying to
> use those components. This is not an easy task in OSGI. Sure, I would
> like Karaf to be able to set startlevels per feature as a way to
> handle bundles that are not properly OSGI'ified. But I think that
> Camel is such a great integration platform that I want it to be
> properly OSGI'ified without having to rely on container specific
> features.
>
> In OSGI, it is common practice to be well aware of you service
> dependencies and handle them. Sometimes this is complex - yes - but it
> is still done.
>
> /Bengt
>
>
> 2010/4/29 Willem Jiang <willem.ji...@gmail.com>:
> > Bengt Rodehav wrote:
> >>
> >> This is exactly the way I was thinking:
> >>
> >> - Define a new interface representing a Camel component ( e g
> >> CamelComponentService)
> >> - Use a service property to identify the specific componente (e g
> >> "camel.component")
> >>
> >> This enables me to wait for a service with that specific service
> >> property to be available. E g in my case I'm using iPOJO to
> >> instantiate OSGI service and can use an annotation similar to the
> >> following:
> >>
> >> @Requires(filter={camel.component=file})
> >> private CamelComponentService fileComponent;
> >
> > Yeah, it's much clear for me.
> > But if your camel route have to deal with more than ten camel components,
> > does it necessary to list all the dependencies with the iPOJO annotation?
> >
> > Willem
> >
> >>
> >> I didn't check that I used the right syntax above. However, the result
> >> is that my service will not be started until a CamelComponentService
> >> with the service property "camel.component" with the value "file" has
> >> been started. I think this would be very useful. It gives Camel a way
> >> to publish the availability of components to the outside world - and
> >> also a way to do it the OSGI way.
> >>
> >> /Bengt
> >>
> >>
> >> 2010/4/29 Guillaume Nodet <gno...@gmail.com>:
> >>>
> >>> We don't have to add anything to the component jars I think. It should
> >>> be
> >>> possible to extend camel-osgi bundle in the following way:
> >>> * when a bundle containing a component is started, register a service
> in
> >>> the osgi registry for the component. I think it should be a new
> >>> interface
> >>> which will allow the creation of components (a component factory)
> >>> registered with an asssociated property to identify the type of
> component
> >>> (file, jms, etc...)
> >>> * modify the osgi component resolver or camel context go to the
> registry
> >>> and wait for some time until all the components are available
> >>> The last part might be a bit more tricky, as we need to find a good
> >>> strategy
> >>> for that. It could also be configurable on the osgi component context
> to
> >>> some degree.
> >>>
> >>> On Thu, Apr 29, 2010 at 04:30, Willem Jiang <willem.ji...@gmail.com>
> >>> wrote:
> >>>
> >>>> Bengt Rodehav wrote:
> >>>>
> >>>>> Thanks for your reply Willem,
> >>>>>
> >>>>> I will try to the bundle dependency of camel-core to my route bundle
> >>>>> as you suggested - sounds like good advice.
> >>>>>
> >>>>> I wasn't sure what you mean by your last paragraph:
> >>>>>
> >>>>> If you need to dependent on some specify component interface will
> >>>>>>
> >>>>>> introduce
> >>>>>> the OSGi related dependency to the camel components.
> >>>>>> We need to find another way to do it.
> >>>>>>
> >>>>> I assume that there was a problem with my suggestion but I didn't
> >>>>> quite understand what.
> >>>>>
> >>>> Oh, that is if you want to publish the camel components into a OSGi
> >>>> service, you can do it in the BundleActivator, or write some XML
> >>>> configuration to leverage Spring DM or Blue Print to do it.
> >>>>
> >>>> If you are using BundleActivator, you will introduce some kind of
> >>>> compile
> >>>> time dependency of OSGi jar. As we also want camel components work
> well
> >>>> as a
> >>>> stand alone Java application, we should avoid introduce this kind of
> >>>> dependency.
> >>>>
> >>>> Maybe the xml configuration is a choice for us.
> >>>>
> >>>> This solution need to your start the Spring-DM or BluePrint container
> >>>> before your camel route bundle to let the container lookup the bundle
> >>>> context for the xml configuration. It seems we are back to your
> original
> >>>> question. And if you start the camel components bundles before you
> start
> >>>> up
> >>>> your camel route bundle, you will not hit this kind of issue.
> >>>>
> >>>> Willem
> >>>>
> >>>>
> >>>>
> >>>>> /Bengt
> >>>>>
> >>>>>
> >>>>>
> >>>>> 2010/4/28 Willem Jiang <willem.ji...@gmail.com>:
> >>>>>
> >>>>>> Hi
> >>>>>>
> >>>>>> Please see my comments in the mail.
> >>>>>>
> >>>>>> Bengt Rodehav wrote:
> >>>>>>
> >>>>>>> I'm using Karaf to deploy my Camel routes. However, I run into
> >>>>>>> problems during startup due to dependency ordering. Some of these
> >>>>>>> ordering problems are OSGI/Karaf specific and have nothing to do
> with
> >>>>>>> Camel. I've discussed them on the Felix user mailing list and I
> have
> >>>>>>> workarounds for that. The Camel problems remain though.
> >>>>>>>
> >>>>>>> When trying to deploy both my routes and the camel bundles in
> Karaf,
> >>>>>>> my routes fail to iniitialize because the referenced camel
> component
> >>>>>>> ("file:" in this case) is not registered in Camel yet. I've tried
> to
> >>>>>>> solve this with workarounds in Karaf. It is possible but not very
> >>>>>>> elegant at all.
> >>>>>>>
> >>>>>> Can you add the bundle dependency of camel-core to your route
> bundle?
> >>>>>>
> >>>>>>> Guillaume Nodet (via us...@felix.apache.org) suggested to me that
> >>>>>>> this
> >>>>>>> is more of a Camel problem than a Karaf problem. In his opinion
> (and
> >>>>>>> mine), it would be much better if Camel published components using
> >>>>>>> OSGI services. That way my services could have a service dependency
> >>>>>>> on
> >>>>>>> the Camel services so that my service would start when the Camel
> >>>>>>> service was available. As I understand it, today Camel just scans
> >>>>>>> bundles as they are started and updates its component registry.
> This
> >>>>>>> makes it impossible for dependent bundles (like my routes) to know
> >>>>>>> whether all the required prerequisites are in place before starting
> >>>>>>> the route.
> >>>>>>>
> >>>>>> That could be a solution of your issue.
> >>>>>>
> >>>>>>> If components were published using a component specific interface,
> I
> >>>>>>> could add a service dependency to that service and wait until it
> >>>>>>> becomes available before trying to start my routes.
> >>>>>>>
> >>>>>>> If you need to dependent on some specify component interface will
> >>>>>>
> >>>>>> introduce
> >>>>>> the OSGi related dependency to the camel components.
> >>>>>> We need to find another way to do it.
> >>>>>>
> >>>>>> Has anyone else had similar issues?What is the recommended
> >>>>>> workaround?
> >>>>>>>
> >>>>>>> Are there any plans for improvement?
> >>>>>>>
> >>>>>>> /Bengt
> >>>>>>>
> >>>>>>>
> >>>>>> Willem
> >>>>>>
> >>>>>>
> >>>
> >>> --
> >>> Cheers,
> >>> Guillaume Nodet
> >>> ------------------------
> >>> Blog: http://gnodet.blogspot.com/
> >>> ------------------------
> >>> Open Source SOA
> >>> http://fusesource.com
> >>>
> >>
> >
> >
>
--
Cheers,
Guillaume Nodet
------------------------
Blog: http://gnodet.blogspot.com/
------------------------
Open Source SOA
http://fusesource.com
