On Dec 5, 2013, at 7:31 AM, Guillaume Nodet <gno...@apache.org> wrote:
> I think that can be argued : it's a big internal change, but not really a > user-facing one. If the work is done in a compatible way (which I think is > doable and should be the goal), it can be done in a minor release, as it > would be almost transparent for the user: i.e. a user should still be able > to deploy his own application without any changes. So I don't think it > requires a major version change. Well, there COULD be an impact…. Right now, some of the features.xml files out there just assume blueprint is available. For example, CXF’s just assumes blueprint is there. They don’t depend on any “blueprint” feature. Thus, an application (or CXF) that would deploy fine on the minimal container out of the box right now would not with 3.1 (or whatever) where blueprint isn’t there. We COULD adjust for this by adding a “blueprint” feature right now (before 3.0 ships) that is relatively redundant with the “framework” feature (or have framework depend on the new blueprint) that the other features.xml could start depending on. That could also be added for a 2.3.x patch as well. Dan > 2013/12/5 Jamie G. <jamie.goody...@gmail.com> > >> Just wanted to contribute my 2 cents -- I'd look at a SCR Karaf for 4.0 - >> removing Blueprint dependencies from the core is too major a change to try >> to introduce it to 2.3.x or 3.0 at this stage. >> >> --Jamie >> >> >> On Thu, Dec 5, 2013 at 8:10 AM, Jean-Baptiste Onofré <j...@nanthrax.net >>> wrote: >> >>> I think we have to distinguish different things: >>> - the learn curve and usage "outside" of Karaf for developers. CDI is >> like >>> EJB, and other framework. >>> - the usage of CDI "inside" an OSGi application or Karaf itself (or for >>> "native" OSGi applications). >>> >>> The fact that Karaf now supports CDI (via pax-cdi) is as good as >>> supporting OpenEJB (in KarafEE), or Spring (in Karaf "natively"). >>> >>> I would not use OpenEJB in Karaf "itself", nor Spring, nor CDI. >>> >>> If a developer wants to create a "generic" application (that can work in >>> both OSGi or non-OSGi containers), CDI is good. >>> If a developer want to create a native OSGi application, I would use >>> natively OSGi "specific" framework (like blueprint). >>> >>> My 0.02€ >>> >>> Regards >>> JB >>> >>> >>> On 12/05/2013 12:06 PM, Christian Schneider wrote: >>> >>>> Probably you are right. >>>> >>>> The reason why I came up with CDI is that it has the potential to be the >>>> core of user applications. >>>> It is fully featured regarding web and persistence if you include other >>>> JavaEE stuff and also defines a standardized extension mechanism. >>>> CDI is also well known to JavaEE developers. So my point is/was that CDI >>>> may be the only thing a developer needs to learn regarding dependency >>>> injection. >>>> >>>> On the other hand a programmer of user applications running on karaf is >>>> quite decoupled from the karaf services and commands. >>>> So it is probably not necessary that he uses and understands the karaf >>>> internals. So from this perspective minimum footprint counts more than >>>> having only one framework. So from this point of view DS really is >>>> better than CDI. >>>> >>>> Another argument supporting this is that while I see most potential in >>>> CDI to take over dependency injection in user space it is far from the >>>> only solution. So there will always be people who use something else. As >>>> karaf needs to support a wide range of frameworks this also speaks for >>>> minimum footprint for karaf's internals. >>>> >>>> Christian >>>> >>>> On 05.12.2013 11:49, Guillaume Nodet wrote: >>>> >>>>> 2013/12/5 Christian Schneider <ch...@die-schneider.net> >>>>> >>>>> Good idea to look into alternatives to blueprint. >>>>>> >>>>>> The big advantage I see for DS is that it is very light weight. I am >> not >>>>>> so sure about its long term future though. >>>>>> I personally think the future of OSGi dependency injection is CDI like >>>>>> pax-cdi + weld or openwebbeans. >>>>>> Of course this is not really near term and far from being a sure bet. >>>>>> Still I think if we switch the DI framework we should >>>>>> also at least experiment with CDI. I am currently working on a karaf >>>>>> tutorial for CDI. The service injections already work very well. >>>>>> I am now looking into jpa support. >>>>>> >>>>>> I disagree. CDI will have the same problems as blueprint, it's an >>>>> application level injection framework, not focused *primarily* on OSGi. >>>>> The lifecycle of CDI beans has to be static, so you have to use >> proxies. >>>>> Blueprint has the exact same problem where the beans lifecycle is >>>>> bound to >>>>> the lifecycle of the container. On the opposite, DS has a better >>>>> lifecycle mechanism for beans which can naturally handle the OSGi >>>>> dynamism. >>>>> >>>>> And CDI would be even more heavyweight than blueprint, so I'd rather >>>>> stick >>>>> with blueprint than switching to CDI, even if it were ready. >>>>> The real benefit of DS is that it has been designed to handle the OSGi >>>>> dynamism, so it does less, but it does it better. >>>>> >>>>> >>>>> In any case I think switching the DI framework should be considered >> for >>>>>> karaf 4. So in this case we have a bit of time to experiment. >>>>>> >>>>>> Christian >>>>>> >>>>>> >>>>>> On 04.12.2013 21:41, Ioannis Canellos wrote: >>>>>> >>>>>> For anyone curious on how Karaf without Blueprint would look like, >>>>>>> here is a karaf branch that is free of blueprint: >>>>>>> https://github.com/iocanel/karaf/tree/karaf-light (it's a fork of >> the >>>>>>> karat-2.3.x branch). >>>>>>> >>>>>>> It is actually a refactored karaf 2.3.x that removes blueprint from >>>>>>> all modules (yet still provides blueprint as feaures). Karaf specific >>>>>>> blueprint namespace handlers have moved to optional bundles so that >>>>>>> they can still be used if needed. >>>>>>> Blueprint has been replaced with Felix SCR (including the shell >>>>>>> commands). Moreover, misc refactorings on features and startup >> bundles >>>>>>> have been performed in order to reduce the size and the amount of >>>>>>> bundles in the minimal distro. >>>>>>> >>>>>>> The result is a minimal distribution that starts 12 bundles [1] (out >>>>>>> of 37 which were part of karaf 2.3.3 minimal distro). 10 of those >>>>>>> bundle were blueprint bundles and the rest are extra noise. >>>>>>> >>>>>>> My motivation behind this refactoring was: >>>>>>> i) I like declarative services more than blueprint. >>>>>>> ii) I've been working on projects that are packaged inside the karaf >>>>>>> minimal distro which would benefit from a smaller size (e.g. >>>>>>> jclouds-cli). >>>>>>> iii) I wanted to make a karaf distro as flexible as possible. >>>>>>> >>>>>>> Please note that my main focus was the minimal distribution and also >>>>>>> this is not 100% polished. >>>>>>> >>>>>>> Enjoy! >>>>>>> >>>>>>> >>>>>>> [1]: The bundle list of the minimal distro: >>>>>>> >>>>>>> ID State Level Name >>>>>>> [ 0] [Active ] [ 0] System Bundle (4.0.3) >>>>>>> [ 1] [Active ] [ 5] OPS4J Pax Url - mvn: (1.3.6) >>>>>>> [ 2] [Active ] [ 5] OPS4J Pax Url - wrap: (1.3.6) >>>>>>> [ 3] [Active ] [ 8] OPS4J Pax Logging - API (1.7.1) >>>>>>> [ 4] [Active ] [ 8] OPS4J Pax Logging - Service (1.7.1) >>>>>>> [ 5] [Active ] [ 10] Apache Felix Configuration Admin Service >>>>>>> (1.6.0) >>>>>>> [ 6] [Active ] [ 11] Apache Felix File Install (3.2.6) >>>>>>> [ 7] [Active ] [ 13] Apache Felix Declarative Services >> (1.6.2) >>>>>>> [ 8] [Active ] [ 25] Apache Karaf :: Shell :: Console >>>>>>> (2.3.4.SNAPSHOT) >>>>>>> [ 9] [Active ] [ 30] Apache Karaf :: Features :: Core >>>>>>> (2.3.4.SNAPSHOT) >>>>>>> [ 10] [Active ] [ 30] Apache Karaf :: Features :: Command >>>>>>> (2.3.4.SNAPSHOT) >>>>>>> [ 11] [Active ] [ 30] Apache Karaf :: Shell :: Log Commands >>>>>>> (2.3.4.SNAPSHOT) >>>>>>> [ 12] [Active ] [ 30] Apache Karaf :: Shell :: OSGi Commands >>>>>>> (2.3.4.SNAPSHOT) >>>>>>> >>>>>>> >>>>>>> -- >>>>>> Christian Schneider >>>>>> http://www.liquid-reality.de >>>>>> >>>>>> Open Source Architect >>>>>> http://www.talend.com >>>>>> >>>>>> >>>>>> >>>> >>>> >>> -- >>> Jean-Baptiste Onofré >>> jbono...@apache.org >>> http://blog.nanthrax.net >>> Talend - http://www.talend.com >>> >> -- Daniel Kulp dk...@apache.org - http://dankulp.com/blog Talend Community Coder - http://coders.talend.com
