Le jeu. 25 mars 2021 à 07:13, Grzegorz Grzybek <gr.grzy...@gmail.com> a
écrit :
> Good morning!
>
> śr., 24 mar 2021 o 19:57 Romain Manni-Bucau <rmannibu...@gmail.com>
> napisał(a):
>
> > in terms of arch yes, the key feature is to have a tree classloader and
> not
> > a graph (drops all the build complexity of OSGi and enable scanning
> > pluggability, yeah).
> >
>
> Graph → Tree sounds like OSGi → JavaEE...
> This can prevent user feature to install a bundle that overrides system
> services.... I know that (without "134 Subsystem Service Specification" and
> without hooks) effectively OSGi runtime is "flat" - every bundle wire is
> equal and resolution rules apply. Also every OSGi service is equal and
> service rank is taken into account.
>
Yes and no, a service registration can still use @Priority or a SPI method
to be sorted, only thing it can prevent is to put conflicting deps in the
same bootstrap classloader (that said these days OSGi is rarely used for
that and since by design the bootstrap loader will be a single app - ie
without any conflict at build time - it is actually sane).
>
> I'm trying to imagine how "it’s powered by OSGi R8 (but you will see that
> it’s more an internal point)" works - is the "Level1: Karaf itself" a
> graph-based layer of bundle classloaders, while applications are given
> their own single classloader (kind of like WebSphere is (was?) based on
> OSGi and WARs/EARs hand single classloader or like Wildfly/EAP that's
> internally a graph of JBoss Modules, while WARs/EARs have single
> classloader)?
>
> java.util.ServiceLoader is dynamic in nature and is a final (IMO) and quite
> elegant discovery solution in tree-(ClassLoader)-based monoliths where you
> "deploy" applications. And it's reflection based.
>
Last point does not have to be true, see some graalvm integrations for
example, it is reflection less depends how you handle the build phase but
being reflection "full" by default enables to keep the tooling (testing)
working without breaking your IDE.
> How about graal/quarkus?
> Let me be clear here - quarkus/graal/native approach is cool and makes Java
> great again™, but I know that "enteprise" still likes the idea of
> "application servers", so I hope Karaf5 is NOT going to be
> "Kubernetes/OpenShift first" - long running processes with reflection and
> dynamic classloading are still relevant.
>
Can you precise it there? Quarkus has two modes: JVM (where it is
equivalent to most microprofile servers without the standard/spec support)
and native mode (where arthur does the same closer to graalvm).
First mode does not need much but last one does not concern karaf 5 AFAIK
since spring-boot has its own graal integration, microprofile servers too
(potentially EE ones too even if I didnt see one yet) and OSGi has its own
through winegroewer so overall Karaf 5 sounds like the aggregator platform
which would fallback on dropping it to be graal compliant (since you'll
drop classloaders which makes all the power of the solution.
>
>
> > In terms of service since the launcher is a monolith it has the key
> > advantage to be able to scan all then dispatch so I guess we can just
> have
> > a ServiceLoader kind of SPI for "module service" impls and order them as
> > needed. a ModuleService { setModuleServiceRegistry(Registry); } would
> then
> > do the trick probably, no need of fancy IoC for such low level framework
> > IMHO.
> >
>
> So clear distinguishing between "applications" and "server plugins" (with
> e.g., replaceable Jackson as JSON provider) - am I interpreting your
> statements correctly Romain?
>
For example yes even if I suspect the services should stick to very
technical layers and isolated from the profile+app loaders so means jackson
from the bootstrap loader shouldnt be usable in an app but you could
configure it to leak (in the profile - ie the parent classes to use).
Very generally services shouldnt leak but profiles will so a provider would
sit in a profile loader IMHO.
Services would be more about logging integration, http integration etc but
wouldnt leak as such but as a karaf 5 plugin instrumenting the profile/app
loader to do the needed replacement, potentially from its own service
loader (service dependent outside of karaf 5 structure).
Thinking out loud, it is very very close to tomee architecture which has
exactly that except the bootstrap loader(s) leaks a lot since it is assumed
not conflicting much and module services are not mainstream app oriented
but EE oriented. But the service and tree of loaders is there so overall if
Karaf5 would leverage the same architecture but power it by the Karaf core
feature inherited from OSGi which is to make any app running in the same
JVM.
A service example could be for example an instrumentation one (since
subclassloaders are karaf controlled) and do the javax -> jakarta migration
on the fly.
>
> regards
> Grzegorz Grzybek
>
>
> >
> > Romain Manni-Bucau
> > @rmannibucau <https://twitter.com/rmannibucau> | Blog
> > <https://rmannibucau.metawerx.net/> | Old Blog
> > <http://rmannibucau.wordpress.com> | Github <
> > https://github.com/rmannibucau> |
> > LinkedIn <https://www.linkedin.com/in/rmannibucau> | Book
> > <
> >
> https://www.packtpub.com/application-development/java-ee-8-high-performance
> > >
> >
> >
> > Le mer. 24 mars 2021 à 19:13, Jean-Baptiste Onofre <j...@nanthrax.net> a
> > écrit :
> >
> > > Hi Romain,
> > >
> > > About OSGi, the way I did it (up to now), it’s as you describe:
> > >
> > > - Karaf "launcher"
> > > — Libraries service
> > > — Profiles service
> > > — SpringBootModuleService
> > > — OsgiModuleService
> > > — MicroprofileModuleService (not yet started)
> > >
> > > The framework is only started when the first OSGi module is deployed.
> > >
> > > If the user deploys only SpringBoot apps in Karaf, he won’t have any
> OSGi
> > > framework.
> > >
> > > Is it what you expected ?
> > >
> > > On Karaf "launcher", we have services available (for now just using
> > > karaf.getService("id")).
> > >
> > > I would love your feedback here. Thoughts ?
> > >
> > > Regards
> > > JB
> > >
> > > > Le 24 mars 2021 à 19:03, Romain Manni-Bucau <rmannibu...@gmail.com>
> a
> > > écrit :
> > > >
> > > > Le mer. 24 mars 2021 à 17:35, Jean-Baptiste Onofre <j...@nanthrax.net>
> a
> > > > écrit :
> > > >
> > > >> Actually, spec like as DocuentBuilder would be rather a library,
> > shared
> > > by
> > > >> all launchers.
> > > >>
> > > >
> > > > Ok but what about jackson? the same?
> > > >
> > > > Joke apart what if spring-boot-app1 uses one impl and
> spring-boot-app2
> > > uses
> > > > another one?
> > > >
> > > > Think at the end there is the JVM, the framework stack which is
> > isolated
> > > > from the app and the apps or it does not move the ball very far from
> > what
> > > > we have today.
> > > >
> > > > Until there is it is EE server - in terms of architecture not
> > scope/impl.
> > > > But the gold of this solution is the ability to configure the leakage
> > > > between layers/profiles to let an app override and potentially
> > > > aggregate/share parts. Obvious example is the http service which can
> > leak
> > > > in spring boot app to override the servlet layer enabling to
> admistrate
> > > it
> > > > globally. Another more advanced solution is to deploy app1 and app2
> > > called
> > > > each other through a kafka topic and replace kafka stack by a local
> > event
> > > > (event admin or not is an impl detail), imagine the perf boost and
> > admin
> > > > simplicity it will bring - all that meaning saving a lot of green
> piece
> > > of
> > > > paper for managers ;).
> > > >
> > > > My only "?" as of today is: why OSGi, this technology is not really
> > > needed
> > > > for such a project (for ex this module provides it wihout OSGi
> > > >
> > >
> >
> https://github.com/Talend/component-runtime/tree/master/container/container-core
> > > )
> > > > and can bring several drawbacks like the slowness to upgrade libs due
> > to
> > > > meta, the blockers to add libs due to the lack of OSGi support, the
> > > > enforcement of architecture teams to adopt OSGi to use that solution
> > etc.
> > > > Why not making OSGi a launcher as spring boot or microprofile, sounds
> > to
> > > be
> > > > at the same level to me.
> > > >
> > > >
> > > >>
> > > >> I would rather say that Karaf 5 is a runtime in the way of launcher.
> > If
> > > we
> > > >> consider an application server as launcher + some key turn features,
> > > then
> > > >> Karaf5 could be considered as an new light app server.
> > > >>
> > > >> You are right: for now, each spring boot app is in its own class
> > loader,
> > > >> embedding its own spring version.
> > > >> However, a spring boot module (karaf 5 terminology uses module more
> > than
> > > >> app) can use a profile. A profile basically brings a class loader
> > where
> > > you
> > > >> can override spring boot module dependencies.
> > > >>
> > > >> Great questions: Karaf 5 MVP is a first attempt, it will be refine
> for
> > > >> sure. I just want to have a first running version to share with you
> > all
> > > and
> > > >> chat about.
> > > >>
> > > >> Regards
> > > >> JB
> > > >>
> > > >>> Le 24 mars 2021 à 16:55, Grzegorz Grzybek <gr.grzy...@gmail.com> a
> > > >> écrit :
> > > >>>
> > > >>> Thanks for the insight ;)
> > > >>>
> > > >>> So first question that comes to my mind is - what will
> > > >>> `javax.xml.parsers.DocumentBuilderFactory#newInstance()` return? I
> > > guess
> > > >> it
> > > >>> depends on the layer.
> > > >>> If this will be (via java.util.ServiceLoader#load()) be configured
> at
> > > low
> > > >>> layer, we can have the "application server aspect"...
> > > >>>
> > > >>> Is "application server" view of Karaf 5 emphasized (existing at
> all?)
> > > >>> somehow?
> > > >>> Is Karaf 5 going to be a "deployment platform to run different
> kinds
> > of
> > > >>> applications"?
> > > >>> For "Spring Boot applications classloaders" - will many "Spring
> Boot
> > > >>> Applications" be separated? If yes, then will each Spring Boot
> > > >> Application
> > > >>> "bring its own Spring"? Or will the Spring libraries be part of
> given
> > > >> Karaf
> > > >>> 5 release?
> > > >>>
> > > >>> sorry for chaotic questions ;) But these are quite natural,
> assuming
> > > >>> "single JVM process" by default (is it?)
> > > >>>
> > > >>> regards
> > > >>> Grzegorz Grzybek
> > > >>>
> > > >>> śr., 24 mar 2021 o 16:46 Jean-Baptiste Onofre <j...@nanthrax.net>
> > > >> napisał(a):
> > > >>>
> > > >>>> Hi,
> > > >>>>
> > > >>>> Actually, you will have three class loader levels:
> > > >>>>
> > > >>>> - Level1: Karaf itself/Karaf services/libraries class loaders
> > > >>>> - Level2: profiles class loader
> > > >>>> - Level3: OSGi module running in the internal framework
> (inheriting
> > > >> first
> > > >>>> level)
> > > >>>> - Level3: Spring Boot applications classloaders
> > > >>>> - Level3: other kind of applications (micro profile, …)
> > > >>>>
> > > >>>> So, basically, framework will be used for OSGi modules mostly.
> > > >>>>
> > > >>>> Today, launchers are "isolated", but I will implement bridges.
> > > >>>>
> > > >>>> Regards
> > > >>>> JB
> > > >>>>
> > > >>>>> Le 24 mars 2021 à 15:37, Grzegorz Grzybek <gr.grzy...@gmail.com>
> a
> > > >>>> écrit :
> > > >>>>>
> > > >>>>> Hello
> > > >>>>>
> > > >>>>> OSGi Core R8 still assumes req/cap model[1] and resolution:
> > > >>>>>
> > > >>>>> The Framework must resolve bundles.
> > > >>>>>>
> > > >>>>>
> > > >>>>> If OSGi (and thus resolution) is _internal_, what kind of
> > "classpath"
> > > >>>>> ("module path"?) will users see? Looking forward for 10000-feet
> > > >> overview
> > > >>>> of
> > > >>>>> Karaf 5 ;)
> > > >>>>>
> > > >>>>> Is Connect specification[2] the inherent part of Karaf5? Is
> > > "classpath"
> > > >>>>> generally flat, hierarchical or irrelevant (?) by default?
> > > >>>>>
> > > >>>>> Anyway - the future looks bright ;)
> > > >>>>>
> > > >>>>> regards
> > > >>>>> Grzegorz Grzybek
> > > >>>>> ===
> > > >>>>> [1]:
> > > >>>>>
> > > >>>>
> > > >>
> > >
> >
> https://docs.osgi.org/specification/osgi.core/8.0.0/framework.module.html#framework.module-resolving
> > > >>>>> [2]:
> > > >>>>>
> > > >>>>
> > > >>
> > >
> >
> https://docs.osgi.org/specification/osgi.core/8.0.0/framework.connect.html
> > > >>>>>
> > > >>>>> śr., 24 mar 2021 o 15:24 Jean-Baptiste Onofre <j...@nanthrax.net>
> > > >>>> napisał(a):
> > > >>>>>
> > > >>>>>> Hi guys,
> > > >>>>>>
> > > >>>>>> As you probably know, we are working on first Karaf 5 MVP, which
> > is
> > > a
> > > >>>>>> complete Karaf refactoring.
> > > >>>>>>
> > > >>>>>> We will share some details soon, but I can already inform you
> that
> > > >>>>>> internally, it’s powered by OSGi R8 (but you will see that it’s
> > more
> > > >> an
> > > >>>>>> internal point).
> > > >>>>>>
> > > >>>>>> Regards
> > > >>>>>> JB
> > > >>>>
> > > >>>>
> > > >>
> > > >>
> > >
> > >
> >
>
