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From Christian Schneider <ch...@die-schneider.net>
Subject Re: [DISCUSSION] Karaf Boot
Date Fri, 11 Sep 2015 07:26:54 GMT
Hi Achim,

very good overview of the problems users face and I also agree with your 
proposed solutions.
Just for pax cdi I think we are not yet there so I would go with 
blueprint generation from CDI annotations for now and switch to
proper pax cdi when it is fully working.

On top I would add that I have the feeling that springsource more or 
less hyped microservices because they know spring does not scale!

The bigger a spring application grows the more you see that it does not 
provide real modularization.
1. All of the dependencies have to be hammered into a flat classpath. 
This works or an astonishingly long time but at some point
in the growth of a project it gets harder and harder.
2. The single spring context. In the end the whole application runs on 
one merged spring contex. All the settings done in the small
contexts scattered around the project artifacts have to work together in 
the big context created at runtime.
3. No enforcement of visibility rules. You can define an API but you 
also have access to all the impls and developers tend to use them
when the time pressure comes.
4. Static setup. Spring has to boot up all beans in the correct order.
5. They tried with OSGi but I think they realized that making spring 
fully OSGi ready is too much work

All this leads to people thinking that an application needs to be split 
into microservices to make the above problems smaller.
Only later they find that implementing microservices is pretty hard. The 
biggest problem is that they may not share a database. So you have
to invent a lot of additonal logic to keep the different databases in 
the same state. Additionally there is security and monitoring which is
also pretty much unsolved in microservices.

If you compare this to a proper OSGi application then the need for the 
spring style microservices is almost not there. Instead you write small
modules with a clearly defined API and boundaries and OSGi services to 
communicate. If you need to cross server boundaries then OSGi remote 
services allow
to extend the OSGi services model to a larger environment.

So I would argue that the microservices hype will not live to its 
promises. People will realize that OSGi provides better solutions with 
less overhead than microservices.
This will take some time of course and we will need to make sure to not 
loose too many people to spring boot in the mean time.

So what we need is a nice way to create microservices in karaf like you 
described. Additionally we should also allow people to just deploy a 
normal OSGi
application in a simple way like you would for a microservice. So I 
think we need to make sure that karaf boot not only works for single 
projects but also
for whole applications in form of a set of bundles. This will allow 
people to transition away from pure microservices when they realize they 
are not as good as they think
while still keeping a lot of the benefits of the small and simple 
deployment unit.

Christian

Am 10.09.2015 um 23:58 schrieb Achim Nierbeck:
> Hi
>
> after reading this thread about two times, I finally understood the
> intention and the confusion in the thread.
> Let me try to summarize this to start some more confusion :-D
>
> Initial Problem:
> - learning OSGi has a steep learning curve
> - initial setup for a new OSGi project needs a lot of infrastructural
> "thingis"
> - doing the "microservice" dance is hard as it requires to much "extras" to
> have a simple REST service
> -- including infrastructure
> - Spring boot brings everything needed in one place in one "application"
> with just annotations
>
> These are the "problems" we know of and if I did get it right are the
> intention for the Karaf-Boot project.
> Now let me try to summarize the idea on how to solve that.
>
>  From a simple Class file with some annotation generate
> - a OSGi service, including OSGi wiring via Blueprint - via an extra maven
> plugin
> - get rid of all those infrastructural "add-ons" for the first OSGi bundle
> by having a easy to use Parent-POM
> - do the microservice - dance by wrapping everything together including CXF
> in a "one-size-fits-all" executable jar, which is a wonna-be-spring-boot
> jar but made of karaf
>
> Now some thoughts of mine ...
> I somehow fear you try to mix several problems and try to solve all of them
> with one go.
> Let's try to analyze those initial problems separately and we might find a
> valid approach.
>
> Learning curve of OSGi:
> right now we have different approaches to make it easier with OSGi.
> - Blueprint
> - DS
> - CDI
> - iPojo
> - Felix DependencyManager
>
> Blueprint just tastes to much like spring xml and actually isn't state of
> the art anymore. You'll get a lot of negative feedback regarding the
> "old-school" xml. It's biggest plus is the Enterprise "features" like JPA
> and JTA, which isn't covered by any other technique right now (unless you
> look at non Apache Hosted OSS projects like Amdatu).
>
> Declarative Services, especially the latest R6 looks rather promising,
> especially in conjunction with MetaType. But we have specialized
> annotations which again don't actually help with the learning curve.
> Another downside is the missing JPA and JTA Enterprise features.
>
> CDI, we have the Pax-CDI project which has been on the way of being the
> reference implementation of the OSGi-CDI spec. Well, we all know how that
> turned out. One of its biggest benefits is definitely the easy transition
> because of the CDI annotation which help a lot with wiring inside a bundle
> and also with extra annotations (@OsgiService) with OSGi-Services. CDI
> though still lacks runtime OSGi annotation support for JPA and JTA if we
> are somehow capable to compensate that, we'll have the required EE stack at
> hand.
>
> iPojo ... sorry never used
>
> Dependency Manager is a bit more low-level compared to DS but seems to have
> a nice DSL for easy wiring of Services.
>
> So do we really need another Build-Time-Annotation which generates another
> "wiring" plan which is used during runtime (exactly what DS already does)?
> Right now I'm not convinced of this. Instead of another generation I would
> prefer to use CDI as it is known to work in classic Spring/EE world and
> OSGi. Instead we should focus on bringing the full support of Enterprise
> style annotations to the OSGi world.
>
>
> Initial Setup for a new OSGi Bundle Project
>
> Instead of a parent POM I think it would be much more beneficial to work
> with a BOM (Bill of Material) for easier development, especially when
> working with std. CDI annotations plus some extra PAX-CDI ones. Maven
> Archetype are actually good enough to create an initial structure for a
> maven project.
> The big benefit of the spring-boot approach is to actually have a bunch of
> different BOMs that can be used to add certain functionalities to the
> project, aka spring-boot-*-starter.
> To start a karaf-boot I think we should first try to have a karaf:run
> available as maven plugin.
>
>
> The microservice dance
>
> actually it's just add a rest-service on top of a OSGi service, that's all
> that is needed in Karaf.
> Right now I'm not in favor of any certain framework. CXF seems a bit
> bloated but is known to work, but requires blueprint.
> Jersey, I've seen that to be working with "plain" OSGi. A bit of polishing
> and it should be quite easy to use, especially with CDI at hand.
>
> But it needs more to dance the microservice dance, you need "small"
> containers ... which is quite contrary to the way Karaf and OSGi in general
> is working with services.
> But this is the point I think the karaf profiles come in handy. You don't
> need a full blown Karaf, just a basic infrastructure with your own Bundle,
> might as well ignore the shell. In the end dump that into a docker
> container and if you need to do a bugfix do it the "docker" - way.
>
>
> spring-boot brings it all in one go
>
> karaf-boot should do the same, but actually I fear we do more then needed.
> For a new Project setup I'd rather would like to see different
> karaf-starter-* BOMs and a karaf:run maven plugin
> Some more docuementation for the profiles of Karaf could also be helpful :D
> to build minimalistic karaf instances runnable in docker containers.
> Regarding the karaf:run it might be interesting to "re-activate" the
> pax:run maven plugin to run nicely with a karaf instance, or use it as
> foundation for the karaf:run maven plugin.
>
>
>
> So in the end, do we really need all this?
> I'm not so sure, but we surely need an easier "to use" approach.
> Therefore we should first focus on having easier setup of bundle
> development.
> -> karaf-boot-starter-* BOMs should take care of that
> -> karaf:run should make it easier to have a running container
>
> Do we need new annotations? I can't see that yet.
> Instead we should/could focus on the following:
> a) make sure DS also is capable to work with JPA/JTA and some other
> enterprise annotations
> b) make sure CDI works with runtime JPA/JTA annotation smoothly
> c) provide more demos and archetypes with OSGi and CDI annotations
>
>
> regards, Achim
>
>
>
>
>
> 2015-09-10 20:41 GMT+02:00 Jean-Baptiste Onofré <jb@nanthrax.net>:
>
>> Thanks Milen,
>>
>> it's an open place to discussion. We just share standpoints and opinions:
>> that's the key part !!!
>>
>> My goal is to give more traction on Karaf by providing easier
>>
>> We all provide valid points, but I think we are not the most setted to
>> argue as we are deeply involved in OSGi and Karaf. The karaf-boot proto
>> came when discussing with new Karaf users, coming from "outside" of OSGi,
>> or people that decided to use spring-boot (even if they like a lot Karaf),
>> just because it's easier. It's hardly frustrating for us as we just need
>> some tooling to provide even more traction. On the container side, I think
>> Karaf is already great, and answers all needs. The part where we should
>> improve what we deliver is around developer tooling: easier, faster, key
>> turn.
>>
>> If karaf-boot will be a success, I don't know (who knows ? ;)). But
>> anyway, it brings points, questions, and identify some missings in the
>> current picture.
>>
>> My $0.01 ;)
>>
>> Regards
>> JB
>>
>>
>> On 09/10/2015 08:02 PM, Milen Dyankov wrote:
>>
>>> Well I was just referring to your example but I get your point. Which
>>> reminds me of EnRoute <http://enroute.osgi.org/> project which despite
>>> the
>>> big names and the most popular OSGI build tool behind it, doesn't seem to
>>> get as much traction as I expected!
>>>
>>> That said, I really admire your enthusiasm and wish KarafBoot can be more
>>> successful that that. I'm not trying to discourage you! Just it seams what
>>> you are after is something that other people have tried already with
>>> questionable success.
>>>
>>> Best,
>>> Milen
>>>
>>>
>>>
>>> On Thu, Sep 10, 2015 at 7:22 PM, Jean-Baptiste Onofré <jb@nanthrax.net>
>>> wrote:
>>>
>>> And how to you deal with jpa, jta, rest, etc with SCR annotations ?
>>>> Regards
>>>> JB
>>>>
>>>>
>>>> On 09/10/2015 07:16 PM, Milen Dyankov wrote:
>>>>
>>>> So correct me if I'm wrong but if I get the sample you provided in the
>>>>> first mail and replace:
>>>>>     - the parent pom with "maven-bundle-plugin"
>>>>>     - @Bean with @Component
>>>>>     - @Init with @Activate
>>>>>
>>>>> wouldn't that have the exact same end result? I mean it obviously differ
>>>>> in
>>>>> terms of what gets generated (Blueprint vs DS) but form end user
>>>>> perspective there is no difference, right?
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Thu, Sep 10, 2015 at 6:55 PM, Jean-Baptiste Onofré <jb@nanthrax.net>
>>>>> wrote:
>>>>>
>>>>> Hey Milen,
>>>>>
>>>>>> Actually, there's too part:
>>>>>> 1/ karaf-boot-starter will do the ready to start artifact, embedding
>>>>>> karaf, but it's another point
>>>>>> 2/ the value of karaf-boot annotations and plugin is first to simplify
>>>>>> the
>>>>>> bundle/artifact ready to be deploy-able into Karaf (generate the
>>>>>> "plumbing"
>>>>>> easily for developers).
>>>>>>
>>>>>> Regards
>>>>>> JB
>>>>>>
>>>>>>
>>>>>> On 09/10/2015 06:50 PM, Milen Dyankov wrote:
>>>>>>
>>>>>> " ... that you deploy in Karaf ..."
>>>>>>
>>>>>>> OK may be I misunderstood the concept. I thought the result is
>>>>>>> standalone
>>>>>>> executable JAR, thus my comments above. If on the other hand I need to
>>>>>>> install Karaf and then deploy my services into it I really don't see
>>>>>>> how
>>>>>>> it
>>>>>>> differs form what people are doing now?
>>>>>>>
>>>>>>> I'm sorry if I'm not making much sense. I didn't have the time to
>>>>>>> experiment with your code and samples so may be I'm missing an
>>>>>>> important
>>>>>>> peace here.
>>>>>>>
>>>>>>> Best,
>>>>>>> Milen
>>>>>>>
>>>>>>>
>>>>>>> On Thu, Sep 10, 2015 at 6:27 PM, Jean-Baptiste Onofré <
>>>>>>> jb@nanthrax.net>
>>>>>>> wrote:
>>>>>>>
>>>>>>> Allow me to disagree: Karaf is a perfect container for microservices.
>>>>>>>
>>>>>>>
>>>>>>>> Image to create a microservice (using karaf-boot) that you deploy in
>>>>>>>> Karaf
>>>>>>>> and use such service in another microservice, all wired with OSGi
>>>>>>>> service
>>>>>>>> and Karaf: we leverage OSGi/Karaf as a microservices container.
>>>>>>>>
>>>>>>>> But even without talking of microservices, new developers to Karaf
>>>>>>>> (and
>>>>>>>> OSGi generally speaking) are frustrated by the effort on non business
>>>>>>>> code
>>>>>>>> to do (I have to write an Activator, or a descriptor, etc, etc).
>>>>>>>> So, a tooling to simplify this is still a valid addition IMHO.
>>>>>>>>
>>>>>>>> Regards
>>>>>>>> JB
>>>>>>>>
>>>>>>>>
>>>>>>>> On 09/10/2015 06:23 PM, Milen Dyankov wrote:
>>>>>>>>
>>>>>>>> I might be wrong but I think the whole success of SpringBoot (apart
>>>>>>>> from
>>>>>>>>
>>>>>>>> having the "Spring" in it) is the microservices hype!
>>>>>>>>> it's quick and easy but most usecases follow the "create one (or
>>>>>>>>> very
>>>>>>>>> few)
>>>>>>>>> service(s), pack them as single executable and access them via REST"
>>>>>>>>> pattern. We can obviously do the same with OSGi and Karaf in
>>>>>>>>> particular
>>>>>>>>> but
>>>>>>>>> personally I think this makes absolutely no sense. In such approach
>>>>>>>>> one
>>>>>>>>> in
>>>>>>>>> not benefiting form OSGi almost at all. Honestly speaking I would
>>>>>>>>> argue
>>>>>>>>> that if one does not understand how OSGi service layer works
>>>>>>>>> (regardless
>>>>>>>>> of
>>>>>>>>> the framework used to register/access services) it makes no sense to
>>>>>>>>> use
>>>>>>>>> OSGi at all.
>>>>>>>>>
>>>>>>>>> Just my 2 cents!
>>>>>>>>>
>>>>>>>>> Regards,
>>>>>>>>> Milen
>>>>>>>>>
>>>>>>>>> On Thu, Sep 10, 2015 at 6:08 PM, Christian Schneider <
>>>>>>>>> chris@die-schneider.net> wrote:
>>>>>>>>>
>>>>>>>>> I already created such a maven plugin in aries. The user can use
>>>>>>>>> standard
>>>>>>>>>
>>>>>>>>> CDI and JEE annotations and the result is blueprint xml.
>>>>>>>>>
>>>>>>>>>> How is the new approach different / better?
>>>>>>>>>>
>>>>>>>>>> Why should it be good for the developer to move away from well
>>>>>>>>>> defined
>>>>>>>>>> standard annotations and use custom annotations that bind him to
>>>>>>>>>> karaf?
>>>>>>>>>> I mean if this is created by the spring guys I know they want to
>>>>>>>>>> catch
>>>>>>>>>> people by perceived simplicity and then make sure to make it
>>>>>>>>>> difficult
>>>>>>>>>> to
>>>>>>>>>> switch. As an open source comminity I do not know why we should do
>>>>>>>>>> something like this.
>>>>>>>>>> Abstracting away from frameworks just means you create another
>>>>>>>>>> layer
>>>>>>>>>> that
>>>>>>>>>> people then also have to learn. There were some cases in the past
>>>>>>>>>> where
>>>>>>>>>> this make sense because the underlying frameworks sucked (like JEE
>>>>>>>>>> 2).
>>>>>>>>>> This
>>>>>>>>>> is not the case today though I think.
>>>>>>>>>>
>>>>>>>>>> What kind of use case do you have in mind? Every project starts
>>>>>>>>>> small
>>>>>>>>>> but
>>>>>>>>>> it needs to be able to grow then. You can not start with custom
>>>>>>>>>> annoations
>>>>>>>>>> and then tell people to later switch to something else when the
>>>>>>>>>> project grows. I think it makes more sense to make it easier for
>>>>>>>>>> people
>>>>>>>>>> to
>>>>>>>>>> use the standard annoations and use the right dependencies.
>>>>>>>>>>
>>>>>>>>>> If we simply provide a tooling that makes it easy to start with SCR
>>>>>>>>>> or
>>>>>>>>>> blueprint we provide much more value for people as thery can then
>>>>>>>>>> grow
>>>>>>>>>> without any breaking changes.
>>>>>>>>>>
>>>>>>>>>> Christian
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Am 10.09.2015 um 17:46 schrieb Jean-Baptiste Onofré:
>>>>>>>>>>
>>>>>>>>>> Because all these annotations are runtime: here we talk about
>>>>>>>>>> tooling
>>>>>>>>>> at
>>>>>>>>>>
>>>>>>>>>> build time.
>>>>>>>>>>
>>>>>>>>>>> More over, the purpose is to provide more high level annotations,
>>>>>>>>>>> which
>>>>>>>>>>> abstract actual annotations/frameworks that we can use under hood.
>>>>>>>>>>>
>>>>>>>>>>> The purpose of centralizing all in karaf-boot is to have a central
>>>>>>>>>>> project: the developer just use karaf-boot, it doesn't really know
>>>>>>>>>>> what
>>>>>>>>>>> technologies are involved behind the scene.
>>>>>>>>>>>
>>>>>>>>>>> For instance, in spring-boot, they use activemq, jersey, etc, but
>>>>>>>>>>> all
>>>>>>>>>>> from spring-boot. The developers don't know a rest service use
>>>>>>>>>>> jersey
>>>>>>>>>>> for
>>>>>>>>>>> instance, it's completely abstracted.
>>>>>>>>>>>
>>>>>>>>>>> Again the purpose is to simplify life for developers: splitting
>>>>>>>>>>> the
>>>>>>>>>>> annotations in different projects introduces complexity (at least
>>>>>>>>>>> to
>>>>>>>>>>> find
>>>>>>>>>>> the dependencies and core import packages).
>>>>>>>>>>>
>>>>>>>>>>> If an advanced developer wants to use CDI, SCR, etc, he can of
>>>>>>>>>>> course.
>>>>>>>>>>>
>>>>>>>>>>> Regards
>>>>>>>>>>> JB
>>>>>>>>>>>
>>>>>>>>>>> On 09/10/2015 05:40 PM, Christian Schneider wrote:
>>>>>>>>>>>
>>>>>>>>>>> I am not really enthusiastic about duplicating functionality of
>>>>>>>>>>> cxf
>>>>>>>>>>> or
>>>>>>>>>>>
>>>>>>>>>>> aries. Aries supports a very nice approach for injections, jpa and
>>>>>>>>>>>
>>>>>>>>>>>> jta.
>>>>>>>>>>>> Why should it make sense to recreate that?
>>>>>>>>>>>> Aries blueprint also has annoation support even in two flavors
>>>>>>>>>>>> (CDI,
>>>>>>>>>>>> custom). How does the new approach interact with this?
>>>>>>>>>>>>
>>>>>>>>>>>> Instead I propose we create support for such annotations in the
>>>>>>>>>>>> respective projects (where they are missing) and concentrate on
>>>>>>>>>>>> karaf
>>>>>>>>>>>> as
>>>>>>>>>>>> a container not an application development framework.
>>>>>>>>>>>> By leveraging the existing frameworks we profit from their own
>>>>>>>>>>>> development teams. Whatever we recreate will have to be developed
>>>>>>>>>>>> by
>>>>>>>>>>>> the
>>>>>>>>>>>> very few resources of the karaf team.
>>>>>>>>>>>>
>>>>>>>>>>>> Christian
>>>>>>>>>>>>
>>>>>>>>>>>> Am 10.09.2015 um 16:53 schrieb Jean-Baptiste Onofré:
>>>>>>>>>>>>
>>>>>>>>>>>> Hi Guillaume,
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> thanks for your feedback.
>>>>>>>>>>>>> I fully agree about providing more high level annotations (it's
>>>>>>>>>>>>> what I
>>>>>>>>>>>>> do with @jpa, @rest, @soap, @jta annotations).
>>>>>>>>>>>>>
>>>>>>>>>>>>> I agree that the current annotations are too low level, and
>>>>>>>>>>>>> blueprint
>>>>>>>>>>>>> "oriented". I just move forward a bit with the current codebase,
>>>>>>>>>>>>> just
>>>>>>>>>>>>> to illustrate karaf-boot usage in the samples.
>>>>>>>>>>>>>
>>>>>>>>>>>>> But again, you are right, and I will create a new annotations
>>>>>>>>>>>>> set.
>>>>>>>>>>>>>
>>>>>>>>>>>>> One of the purpose of karaf-boot annotations is to "abstract"
>>>>>>>>>>>>> the
>>>>>>>>>>>>> actual code/artifact that we generate. So, if now we generate
>>>>>>>>>>>>> blueprint, without changing the karaf-boot annotations, we will
>>>>>>>>>>>>> be
>>>>>>>>>>>>> able to generate something else (why not SCR, etc).
>>>>>>>>>>>>>
>>>>>>>>>>>>> I agree with a BOM, but I think it's interesting to provide
>>>>>>>>>>>>> both:
>>>>>>>>>>>>> - providing a ready to use parent pom allows developers to
>>>>>>>>>>>>> create
>>>>>>>>>>>>> a
>>>>>>>>>>>>> very simple pom.xml where all plugins and dependencies are
>>>>>>>>>>>>> already
>>>>>>>>>>>>> defined
>>>>>>>>>>>>> - for more advanced devs, they can create their own pom.xml
>>>>>>>>>>>>> starting
>>>>>>>>>>>>> from the BOM or archetype.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Thanks again for your feedback !
>>>>>>>>>>>>>
>>>>>>>>>>>>> Regards
>>>>>>>>>>>>> JB
>>>>>>>>>>>>>
>>>>>>>>>>>>> On 09/10/2015 04:44 PM, Guillaume Nodet wrote:
>>>>>>>>>>>>>
>>>>>>>>>>>>> I like the idea.
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> For the annotations, we need to keep really high level.  The
>>>>>>>>>>>>>> annotations in
>>>>>>>>>>>>>> the code base right now are much too close to blueprint.
>>>>>>>>>>>>>> I think we need to grab a small enough subset so that the
>>>>>>>>>>>>>> annotations
>>>>>>>>>>>>>> are
>>>>>>>>>>>>>> easy to understand for beginners and without any ambiguities,
>>>>>>>>>>>>>> even
>>>>>>>>>>>>>> at
>>>>>>>>>>>>>> the
>>>>>>>>>>>>>> cost of features.
>>>>>>>>>>>>>> For example, I think we should restrict to constructor
>>>>>>>>>>>>>> injection,
>>>>>>>>>>>>>> so
>>>>>>>>>>>>>> that
>>>>>>>>>>>>>> we don't have any bind / rebind / init methods.  We simply need
>>>>>>>>>>>>>> an
>>>>>>>>>>>>>> optional
>>>>>>>>>>>>>> @Destroy.  In case the dependencies change at runtime, simply
>>>>>>>>>>>>>> destroy
>>>>>>>>>>>>>> the
>>>>>>>>>>>>>> bean / service and recreate it the dependencies are still met
>>>>>>>>>>>>>> after
>>>>>>>>>>>>>> the
>>>>>>>>>>>>>> change.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> If blueprint is to be hidden completely, we may find a better
>>>>>>>>>>>>>> alternative
>>>>>>>>>>>>>> in SCR or even Felix Dependency Manager, but it does not matter
>>>>>>>>>>>>>> too
>>>>>>>>>>>>>> much
>>>>>>>>>>>>>> for now.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I agree with the idea of using a BOM instead of a parent if
>>>>>>>>>>>>>> possible.  I'm
>>>>>>>>>>>>>> not very familiar, but this is less invasive.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> The real problems will come with the support of higher level
>>>>>>>>>>>>>> annotations
>>>>>>>>>>>>>> for JAXRS, JPA, etc...
>>>>>>>>>>>>>> Not really sure how to handle those yet...
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> 2015-09-09 16:32 GMT+02:00 Jean-Baptiste Onofré <
>>>>>>>>>>>>>> jb@nanthrax.net
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> :
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Hi all,
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I worked on a prototype about Karaf Boot.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Let me give you some backgrounds and discuss about that all
>>>>>>>>>>>>>>> together.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>        Why Karaf Boot ?
>>>>>>>>>>>>>>>        ----------------
>>>>>>>>>>>>>>> When you develop artifacts (bundles) to be deployed in Karaf,
>>>>>>>>>>>>>>> you
>>>>>>>>>>>>>>> can see
>>>>>>>>>>>>>>> that the actual time that you spend on your business code is
>>>>>>>>>>>>>>> finally
>>>>>>>>>>>>>>> largely less important that all the plumbing effort that you
>>>>>>>>>>>>>>> have
>>>>>>>>>>>>>>> to
>>>>>>>>>>>>>>> do
>>>>>>>>>>>>>>> (writing OSGi Activator, or blueprint/scr descriptor, etc).
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> It means that your "go to market" is longer, and we should
>>>>>>>>>>>>>>> provide
>>>>>>>>>>>>>>> something that allows you to focus on your code.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Even if SCR annotations is a very good step forward, some use
>>>>>>>>>>>>>>> cases
>>>>>>>>>>>>>>> are
>>>>>>>>>>>>>>> not so easy to do (JPA, JTA for instance).
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> And anyway, you have to prepare your pom.xml with different
>>>>>>>>>>>>>>> plugin
>>>>>>>>>>>>>>> and
>>>>>>>>>>>>>>> dependency.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Moreover, when you have your artifacts, you have to prepare
>>>>>>>>>>>>>>> Karaf
>>>>>>>>>>>>>>> container, and deploy those artifacts there. Even if it's
>>>>>>>>>>>>>>> "container"
>>>>>>>>>>>>>>> approach is the most important for me, we can give even more
>>>>>>>>>>>>>>> flexibility by
>>>>>>>>>>>>>>> providing a way to embed and prepare Karaf in a ready to
>>>>>>>>>>>>>>> execute
>>>>>>>>>>>>>>> jar/artifact.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>        What is Karaf Boot ?
>>>>>>>>>>>>>>>        --------------------
>>>>>>>>>>>>>>> Karaf Boot provides four components:
>>>>>>>>>>>>>>> * karaf-boot-parent is the Maven parent pom that your project
>>>>>>>>>>>>>>> just
>>>>>>>>>>>>>>> inherit: that's all ! All plugins, dependencies, etc are
>>>>>>>>>>>>>>> described
>>>>>>>>>>>>>>> in this
>>>>>>>>>>>>>>> parent, you even don't have to define packaging as bundle,
>>>>>>>>>>>>>>> standard
>>>>>>>>>>>>>>> jar is
>>>>>>>>>>>>>>> fine.
>>>>>>>>>>>>>>> * karaf-boot (coming with karaf-boot-parent) provides
>>>>>>>>>>>>>>> annotations
>>>>>>>>>>>>>>> that you
>>>>>>>>>>>>>>> use directly in your business code (like @Bean, @Service,
>>>>>>>>>>>>>>> @Reference,
>>>>>>>>>>>>>>> @Inject, etc): again, your focus on your code, karaf-boot
>>>>>>>>>>>>>>> deals
>>>>>>>>>>>>>>> with
>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>> plumbing.
>>>>>>>>>>>>>>> * karaf-boot-maven-plugin (coming with karaf-boot-parent) scan
>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>> classes
>>>>>>>>>>>>>>> and generate a blueprint XML. For now, I'm using blueprint
>>>>>>>>>>>>>>> generation
>>>>>>>>>>>>>>> (because we can cover lot of use cases, for instance, I plan
>>>>>>>>>>>>>>> to
>>>>>>>>>>>>>>> provide
>>>>>>>>>>>>>>> @rest annotation that will generate blueprint XML with cxf
>>>>>>>>>>>>>>> jaxrs
>>>>>>>>>>>>>>> server,
>>>>>>>>>>>>>>> etc).
>>>>>>>>>>>>>>> * karaf-boot-starter is the module providing a convenient way
>>>>>>>>>>>>>>> to
>>>>>>>>>>>>>>> embed,
>>>>>>>>>>>>>>> configure and bootstrap Karaf.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Just to illustrate this, let's take a look on the
>>>>>>>>>>>>>>> karaf-boot-sample-simple.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> The pom.xml is really simple:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> <?xml version="1.0" encoding="UTF-8"?>
>>>>>>>>>>>>>>> <project xmlns="http://maven.apache.org/POM/4.0.0"
>>>>>>>>>>>>>>> xmlns:xsi="
>>>>>>>>>>>>>>> http://www.w3.org/2001/XMLSchema-instance"
>>>>>>>>>>>>>>> xsi:schemaLocation="
>>>>>>>>>>>>>>> http://maven.apache.org/POM/4.0.0
>>>>>>>>>>>>>>> http://maven.apache.org/xsd/maven-4.0.0.xsd">
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>           <modelVersion>4.0.0</modelVersion>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>           <parent>
>>>>>>>>>>>>>>> <groupId>org.apache.karaf.boot</groupId>
>>>>>>>>>>>>>>> <artifactId>karaf-boot-parent</artifactId>
>>>>>>>>>>>>>>>               <version>1.0.0-SNAPSHOT</version>
>>>>>>>>>>>>>>>           </parent>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> <artifactId>karaf-boot-sample-simple</artifactId>
>>>>>>>>>>>>>>>           <version>1.0.0-SNAPSHOT</version>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> </project>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> You can see, the only thing that the developer has to do:
>>>>>>>>>>>>>>> define
>>>>>>>>>>>>>>> karaf-boot-parent as parent pom. That's all.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Now, in the code, you have just one bean that we want to run:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> package org.apache.karaf.boot.sample.simple;
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> import org.apache.karaf.boot.Bean;
>>>>>>>>>>>>>>> import org.apache.karaf.boot.Init;
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> @Bean(id = "simple-bean")
>>>>>>>>>>>>>>> public class SimpleBean {
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>           @Init
>>>>>>>>>>>>>>>           public void simple() {
>>>>>>>>>>>>>>>               System.out.println("Hello world");
>>>>>>>>>>>>>>>           }
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> }
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> You can see the @Bean and @Init karaf-boot annotations. The
>>>>>>>>>>>>>>> karaf-boot-maven-plugin will generate the blueprint descriptor
>>>>>>>>>>>>>>> using
>>>>>>>>>>>>>>> this.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>        Current Status
>>>>>>>>>>>>>>>        --------------
>>>>>>>>>>>>>>> I pushed Karaf Boot structure there:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> https://github.com/jbonofre/karaf-boot
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> It's a mix of rewrapping of existing code (from aries,
>>>>>>>>>>>>>>> pax-exam,
>>>>>>>>>>>>>>> etc) and
>>>>>>>>>>>>>>> additions.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> I created the annotations, I'm now working on the
>>>>>>>>>>>>>>> karaf-boot-maven-plugin
>>>>>>>>>>>>>>> based on Christian's work in aries (I'm actually scanning the
>>>>>>>>>>>>>>> boot
>>>>>>>>>>>>>>> annotations now, and generating the XML).
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> I will push new changes later today and tomorrow.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>        Open Questions
>>>>>>>>>>>>>>>        ---------------
>>>>>>>>>>>>>>> * For now, I would prefer to be 'artifacts' and 'resources'
>>>>>>>>>>>>>>> generator: I
>>>>>>>>>>>>>>> think it's better than to depend to a feature running in
>>>>>>>>>>>>>>> Karaf,
>>>>>>>>>>>>>>> but
>>>>>>>>>>>>>>> it's
>>>>>>>>>>>>>>> open to discussion.
>>>>>>>>>>>>>>> * I'm now generating blueprint. Probably native OSGi or scr
>>>>>>>>>>>>>>> generation can
>>>>>>>>>>>>>>> make sense.
>>>>>>>>>>>>>>> * I'm generating bundles: thanks to the Karaf4 features
>>>>>>>>>>>>>>> resolver,
>>>>>>>>>>>>>>> as
>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>> bundles provide requirements/capabilities metadata, I think
>>>>>>>>>>>>>>> it's a
>>>>>>>>>>>>>>> good
>>>>>>>>>>>>>>> start. However, maybe it's worth to be able to create
>>>>>>>>>>>>>>> features,
>>>>>>>>>>>>>>> kar,
>>>>>>>>>>>>>>> profile.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Thoughts ?
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>>> Regards
>>>>>>>>>>>>>>> JB
>>>>>>>>>>>>>>> --
>>>>>>>>>>>>>>> Jean-Baptiste Onofré
>>>>>>>>>>>>>>> jbonofre@apache.org
>>>>>>>>>>>>>>> http://blog.nanthrax.net
>>>>>>>>>>>>>>> Talend - http://www.talend.com
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>> Jean-Baptiste Onofré
>>>>>>>> jbonofre@apache.org
>>>>>>>> http://blog.nanthrax.net
>>>>>>>> Talend - http://www.talend.com
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>> --
>>>>>>>
>>>>>> Jean-Baptiste Onofré
>>>>>> jbonofre@apache.org
>>>>>> http://blog.nanthrax.net
>>>>>> Talend - http://www.talend.com
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>> --
>>>> Jean-Baptiste Onofré
>>>> jbonofre@apache.org
>>>> http://blog.nanthrax.net
>>>> Talend - http://www.talend.com
>>>>
>>>>
>>>
>>>
>> --
>> Jean-Baptiste Onofré
>> jbonofre@apache.org
>> http://blog.nanthrax.net
>> Talend - http://www.talend.com
>>
>
>


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