Flink's classloading is different from Hadoop's. In Hadoop, the entire JVM is started with all classes (including the user jar) in the classpath already. In Flink, jars are added dymanically, to running JVMs with custom class loaders. That way, running worker/master processes can accept new jars without restarts. Important for low-latency, shells, etc
Flink itself respects these classloaders whenever dynamically looking up a class. It may be that Closure is written such that it can only dynamically instantiate what is the original classpath. On Fri, Dec 11, 2015 at 1:31 AM, Nick Dimiduk <ndimi...@apache.org> wrote: > As far as the jvm is concerned, clojure is just another library. You should > be able to package it up like any other dependency and submit the job. > That's always how it worked in Hadoop/MR anyway... > > On Thu, Dec 10, 2015 at 3:22 PM, Matthias J. Sax <mj...@apache.org> wrote: > > > Thanks for this idea. > > > > I extended my pom to include clojure-1.5.1.jar in my program jar. > > However, the problem is still there... I did some research on the > > Internet, and it seems I need to mess around with Clojure's class > > loading strategy... > > > > -Matthias > > > > On 12/10/2015 06:47 PM, Nick Dimiduk wrote: > > > I think Mattias's project is using maven though -- there's a pom in the > > > project that doesn't look generated. If you want to do it from lein, > > maybe > > > my old lein-hadoop [0] plugin can help? > > > > > > [0]: https://github.com/ndimiduk/lein-hadoop > > > > > > On Thu, Dec 10, 2015 at 8:54 AM, Robert Metzger <rmetz...@apache.org> > > wrote: > > > > > >> I had the same though as Nick. Maybe Leiningen allows to somehow > build a > > >> fat-jar containing the clojure standard library. > > >> > > >> On Thu, Dec 10, 2015 at 5:51 PM, Nick Dimiduk <ndimi...@apache.org> > > wrote: > > >> > > >>> What happens when you follow the packaging examples provided in the > > flink > > >>> quick start archetypes? These have the maven-foo required to package > an > > >>> uberjar suitable for flink submission. Can you try adding that step > to > > >> your > > >>> pom.xml? > > >>> > > >>> On Thursday, December 10, 2015, Stephan Ewen <se...@apache.org> > wrote: > > >>> > > >>>> This is a problem in Java. > > >>>> I think you cannot dynamically modify the initial system class > loader. > > >>>> > > >>>> What most apps do is check for the thread context class loader when > > >>>> dynamically loading classes. We can check and make sure that one is > > >> set, > > >>>> but if Closure does not respect that, we have a problem. > > >>>> Then Closure is not built for dynamic class loading. > > >>>> > > >>>> > > >>>> > > >>>> On Thu, Dec 10, 2015 at 5:15 PM, Matthias J. Sax <mj...@apache.org > > >>>> <javascript:;>> wrote: > > >>>> > > >>>>> Would it make sense (if possible?) for Flink to add the user jar > > >>>>> dynamically to it's own classpath so Clojure can find it? Or > somehow > > >>>>> modify Clojure's class loader? > > >>>>> > > >>>>> The jars in lib are added to the classpath at startup. This makes > it > > >>>>> practically impossible to execute a Flink program that is written > in > > >>>>> Clojure right now... > > >>>>> > > >>>>> > > >>>>> On 12/10/2015 05:09 PM, Aljoscha Krettek wrote: > > >>>>>> Clojure is not considering the user-jar when trying to load the > > >>> class. > > >>>>>> > > >>>>>>> On 10 Dec 2015, at 17:05, Matthias J. Sax <mj...@apache.org > > >>>> <javascript:;>> wrote: > > >>>>>>> > > >>>>>>> Hi Squirrels, > > >>>>>>> > > >>>>>>> I was playing with a Flink Clojure WordCount example today. > > >>>>>>> > https://github.com/mjsax/flink-external/tree/master/flink-clojure > > >>>>>>> > > >>>>>>> After building the project with "mvn package" I tried to submit > it > > >>> to > > >>>> a > > >>>>>>> local cluster. Before I started the cluster, I manually copied > > >>>>>>> "clojure-1.5.1.jar" into Flink's lib folder. > > >>>>>>> > > >>>>>>>> cp ~/.m2/repository/org/clojure/clojure/1.5.1/clojure-1.5.1.jar > > >>> lib/ > > >>>>>>>> bin/start-local.sh > > >>>>>>> > > >>>>>>> However, when submitting the jar, I get an exception: > > >>>>>>> > > >>>>>>>> bin/flink run -c org.apache.flink.clojure.WordCount > > >>>>>>> > > >>>>> > > >>>> > > >>> > > >> > > > ~/workspace_flink/flink-external/flink-clojure/target/flink-clojure-0.10.0.jar > > >>>>>>> > > >>>>>>> > > >>>>>>>> ------------------------------------------------------------ > > >>>>>>>> The program finished with the following exception: > > >>>>>>>> > > >>>>>>>> org.apache.flink.client.program.ProgramInvocationException: The > > >>>>> program's entry point class 'org.apache.flink.clojure.WordCount' > > >> threw > > >>> an > > >>>>> error during initialization. > > >>>>>>>> at > > >>>>> > > >>>> > > >>> > > >> > > > org.apache.flink.client.program.PackagedProgram.loadMainClass(PackagedProgram.java:585) > > >>>>>>>> at > > >>>>> > > >>>> > > >>> > > >> > > > org.apache.flink.client.program.PackagedProgram.<init>(PackagedProgram.java:195) > > >>>>>>>> at > > >>>>> > > >> org.apache.flink.client.CliFrontend.buildProgram(CliFrontend.java:784) > > >>>>>>>> at org.apache.flink.client.CliFrontend.run(CliFrontend.java:288) > > >>>>>>>> at > > >>>>> > > >>>> > > >>> > > >> > > > org.apache.flink.client.CliFrontend.parseParameters(CliFrontend.java:1050) > > >>>>>>>> at > > >> org.apache.flink.client.CliFrontend.main(CliFrontend.java:1103) > > >>>>>>>> Caused by: java.lang.ExceptionInInitializerError > > >>>>>>>> at java.lang.Class.forName0(Native Method) > > >>>>>>>> at java.lang.Class.forName(Class.java:278) > > >>>>>>>> at > > >>>>> > > >>>> > > >>> > > >> > > > org.apache.flink.client.program.PackagedProgram.loadMainClass(PackagedProgram.java:578) > > >>>>>>>> ... 5 more > > >>>>>>>> Caused by: java.io.FileNotFoundException: Could not locate > > >>>>> org/apache/flink/clojure/WordCount__init.class or > > >>>>> org/apache/flink/clojure/WordCount.clj on classpath: > > >>>>>>>> at clojure.lang.RT.load(RT.java:443) > > >>>>>>>> at clojure.lang.RT.load(RT.java:411) > > >>>>>>>> at clojure.core$load$fn__5018.invoke(core.clj:5530) > > >>>>>>>> at clojure.core$load.doInvoke(core.clj:5529) > > >>>>>>>> at clojure.lang.RestFn.invoke(RestFn.java:408) > > >>>>>>>> at clojure.lang.Var.invoke(Var.java:415) > > >>>>>>>> at org.apache.flink.clojure.WordCount.<clinit>(Unknown Source) > > >>>>>>>> ... 8 more > > >>>>>>> > > >>>>>>> I am not sure why the class is not found. It is contained in the > > >> jar > > >>>>>>> file. I can fix this error by copying the user jar > > >>>>>>> (flink-clojure-0.10.0.jar) into Flink's lib-folder. > > >>>>>>> > > >>>>>>> It seems, that Flink is not looking into the user-jar when > loading > > >>>> this > > >>>>>>> class. Can anybody explain why? > > >>>>>>> > > >>>>>>> Thx. > > >>>>>>> > > >>>>>>> -Matthias > > >>>>>>> > > >>>>>> > > >>>>> > > >>>>> > > >>>> > > >>> > > >> > > > > > > > >
