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From Sergi Vladykin <sergi.vlady...@gmail.com>
Subject Re: Ignite modularisation: client/server separation
Date Mon, 03 Aug 2015 13:23:11 GMT

As far as I understand your main concern is that Ignite is incompatible
with OSGi (other points seem to be more about your personal feelings about
"right engineering practices" than about real problems). I believe that we
can achieve this compatibility without such a big refactoring of
everything. But do we really need that if it is not a requirement for

BTW client/server API of Ignite is intentionally unified to make it easier
to use (simply switch one flag in config instead of rewriting your code to
completely different API). In this case unification works better than
separation of concerns.


2015-08-03 14:31 GMT+03:00 Raul Kripalani <raulk@apache.org>:

> Hello guys,
> Spoke to Dmitriy over the weekend about the modularisation of Ignite.
> At Apache Camel we strive to make all our components (including the future
> camel-ignite) OSGi compatible because have a significant user base
> deploying Camel apps on Apache Karaf.
> I see some groundwork before we can aspire to make OSGi components
> communicate with Ignite:
>    * There seems to be no concept of a client. Client-side and server-side
> coexist in ignite-core. There's no code separation, so a client wanting to
> communicate with an Ignite topology will end up importing the server-side
> implementation too.
>    * ... and the server-side implementation uses classloading constructs
> (e.g. Zero Deployment) which may prove hard to engineer for compatibility
> with OSGi. This re-enginering is a waste of time IMHO because there's no
> interest in running Ignite servers on top of OSGi - only clients.
>    * The ignite-core JAR (6.7mb) is too heavy for a component that's
> nothing but a client. Some average Java client API sizes for reference:
> hazelcast (400kb), activemq-client (1.2 mb), kafka (300kb).
>    * Possible dependency leak. Currently not a problem as we lack 3rd party
> deps in ignite-core. But if we introduce any, we'll impose our dep versions
> on the client creating possible classpath hell. Or seen from another
> perspective: I don't know the reason we have no 3rd party deps, and I'm
> sure we've had to reinvent the wheel at some point... Perhaps we avoided
> them because we knew we would be imposing them on the client? If that's the
> case, separating server and client will bring lots of flexibility.
>    * This architecture/design entails a lack of separation of concerns,
> IMO. While it's true that a client can start an embedded Ignite instance
> (and for that it'll need the server-side code), not all clients will do. In
> my opinion, ignite-java-client (hypothetical name) should discover
> ignite-core (just the server-side impl) in the classpath if starting an
> embedded Ignite is requested.
> What's your opinion? Obviously such a refactoring is a large undertaking
> and not for immediate action. If the community shares this vision, I would
> start thinking about this for 2.0.
> P.S.: With regards to Camel, a warning on the camel-ignite doc page for not
> being OSGi-compliant will suffice.
> Regards,
> *Raúl Kripalani*
> Apache Camel PMC Member & Committer | Enterprise Architect, Open Source
> Integration specialist
> http://about.me/raulkripalani | http://www.linkedin.com/in/raulkripalani
> http://blog.raulkr.net | twitter: @raulvk

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