(DEPRECATED) Apache Flink User Mailing List archive.

Re: [Stateful Functions] Help for calling remote stateful function (written in Python)

Posted by Igal Shilman on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/Stateful-Functions-Help-for-calling-remote-stateful-function-written-in-Python-tp43283p43285.html

Hello!

Your analysis is correct, indeed what is passed is whatever is being handed to withMessageBody(..).
Starting with StateFun 3.0, if you need to send a message to a remote function the message needs to be a TypedValue.

You can create an instance of TypedValue manually, or you can add a dependency on the Java SDK and use the MessageBuilder to
extract TypedValues.

I think that you are right, the DataStream <-> Remote functions could be a little bit improved, I will file a JIRA issue
for that!

A side question is there a particular reason that you chose to use the DataStream SDK v.s the other deployment options?

Thanks,
Igal.





On Tue, Apr 27, 2021 at 5:31 PM Bonino Dario <[hidden email]> wrote:

Dear List,

I am trying to call a sample stateful function defined in Python, using the Stateful Function Python SDK, from a Flink pipeline. I am building upon the examples provided for the  SDK for Flink DataStream Integration but I am currently stuck on a type cast issue that I am not able to overcome, even by looking at the flink-statefun sources. I am sure that I am probably doing something wrong.

In the flink pipeline (of which an excerpt is reported below), I load a set of users from a CSV file and create a Datastream<User> where User is a protobuf v3 generated class. Given this stream, the base idea is to forward the stream to a remote function (written in python using the sdk) that basically unpacks the user object, extracts the user id and provides it back as a String.


val REMOTE_GREET = FunctionType("com.me.try", "echo_user_id")
val GREETINGS = EgressIdentifier<String>("com.me.try", "out", String::class.java)

@JvmStatic
fun main(args: Array<String>) {
    val env = StreamExecutionEnvironment.getExecutionEnvironment()
    val usersCsv = env.readTextFile("input/users.csv")
    val users = createUsersStream(usersCsv).shuffle()

    val statefunConfig = StatefulFunctionsConfig.fromEnvironment(env)
    statefunConfig.factoryType = MessageFactoryType.WITH_PROTOBUF_PAYLOADS

    val usersIngress: DataStream<RoutableMessage> = users.map { user ->
        RoutableMessageBuilder.builder()
            .withTargetAddress(REMOTE_GREET, user.userId.toString())
            .withMessageBody(user)
            .build()
    }


    val predictEgress = StatefulFunctionDataStreamBuilder.builder("test")
        .withDataStreamAsIngress(usersIngress)
        .withRequestReplyRemoteFunction(
            RequestReplyFunctionBuilder
                .requestReplyFunctionBuilder(REMOTE_GREET, URI.create("http://127.0.0.1:8000/statefun"))
                .withMaxRequestDuration(Duration.ofSeconds(15))
                .withMaxNumBatchRequests(500)
        )
        .withEgressId(GREETINGS)
        .withConfiguration(statefunConfig)
        .build(env)

    val output = predictEgress.getDataStreamForEgressId(GREETINGS)

    output.print()
    env.execute("Hello stateful!!")
}

Unfortunately, while the Python function seems to be working (tests build by following the Ververica workshop repository about Stateful functions are up and consistently running) and it is listening at the provided address (http://127.0.0.1:8000/statefun), the Kotlin pipeline (above) fails with a type cast error, which occurs before actually calling the remote function, at line 90 of the org.apache.flink.statefun.flink.core.reqreply.RequestReplyFunction. The reported exception is:


Exception in thread "main" org.apache.flink.runtime.client.JobExecutionException: Job execution failed. at org.apache.flink.runtime.jobmaster.JobResult.toJobExecutionResult(JobResult.java:144) at org.apache.flink.runtime.minicluster.MiniClusterJobClient.lambda$getJobExecutionResult$2(MiniClusterJobClient.java:117) at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:642) at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506) at java.base/java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:2073) at org.apache.flink.runtime.rpc.akka.AkkaInvocationHandler.lambda$invokeRpc$0(AkkaInvocationHandler.java:238) at java.base/java.util.concurrent.CompletableFuture.uniWhenComplete(CompletableFuture.java:859) at java.base/java.util.concurrent.CompletableFuture$UniWhenComplete.tryFire(CompletableFuture.java:837) at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506) at java.base/java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:2073) at org.apache.flink.runtime.concurrent.FutureUtils$1.onComplete(FutureUtils.java:1046) at akka.dispatch.OnComplete.internal(Future.scala:264) at akka.dispatch.OnComplete.internal(Future.scala:261) at akka.dispatch.japi$CallbackBridge.apply(Future.scala:191) at akka.dispatch.japi$CallbackBridge.apply(Future.scala:188) at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:60) at org.apache.flink.runtime.concurrent.Executors$DirectExecutionContext.execute(Executors.java:73) at scala.concurrent.impl.CallbackRunnable.executeWithValue(Promise.scala:68) at scala.concurrent.impl.Promise$DefaultPromise.$anonfun$tryComplete$1(Promise.scala:284) at scala.concurrent.impl.Promise$DefaultPromise.$anonfun$tryComplete$1$adapted(Promise.scala:284) at scala.concurrent.impl.Promise$DefaultPromise.tryComplete(Promise.scala:284) at akka.pattern.PromiseActorRef.$bang(AskSupport.scala:573) at akka.pattern.PipeToSupport$PipeableFuture$$anonfun$pipeTo$1.applyOrElse(PipeToSupport.scala:22) at akka.pattern.PipeToSupport$PipeableFuture$$anonfun$pipeTo$1.applyOrElse(PipeToSupport.scala:21) at scala.concurrent.Future.$anonfun$andThen$1(Future.scala:532) at scala.concurrent.impl.Promise.liftedTree1$1(Promise.scala:29) at scala.concurrent.impl.Promise.$anonfun$transform$1(Promise.scala:29) at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:60) at akka.dispatch.BatchingExecutor$AbstractBatch.processBatch(BatchingExecutor.scala:55) at akka.dispatch.BatchingExecutor$BlockableBatch.$anonfun$run$1(BatchingExecutor.scala:91) at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12) at scala.concurrent.BlockContext$.withBlockContext(BlockContext.scala:81) at akka.dispatch.BatchingExecutor$BlockableBatch.run(BatchingExecutor.scala:91) at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:40) at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(ForkJoinExecutorConfigurator.scala:44) at akka.dispatch.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) at akka.dispatch.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) at akka.dispatch.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) at akka.dispatch.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)Caused by: org.apache.flink.runtime.JobException: Recovery is suppressed by NoRestartBackoffTimeStrategy at org.apache.flink.runtime.executiongraph.failover.flip1.ExecutionFailureHandler.handleFailure(ExecutionFailureHandler.java:118) at org.apache.flink.runtime.executiongraph.failover.flip1.ExecutionFailureHandler.getFailureHandlingResult(ExecutionFailureHandler.java:80) at org.apache.flink.runtime.scheduler.DefaultScheduler.handleTaskFailure(DefaultScheduler.java:233) at org.apache.flink.runtime.scheduler.DefaultScheduler.maybeHandleTaskFailure(DefaultScheduler.java:224) at org.apache.flink.runtime.scheduler.DefaultScheduler.updateTaskExecutionStateInternal(DefaultScheduler.java:215) at org.apache.flink.runtime.scheduler.SchedulerBase.updateTaskExecutionState(SchedulerBase.java:665) at org.apache.flink.runtime.scheduler.SchedulerNG.updateTaskExecutionState(SchedulerNG.java:89) at org.apache.flink.runtime.jobmaster.JobMaster.updateTaskExecutionState(JobMaster.java:447) at jdk.internal.reflect.GeneratedMethodAccessor15.invoke(Unknown Source) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:566) at org.apache.flink.runtime.rpc.akka.AkkaRpcActor.handleRpcInvocation(AkkaRpcActor.java:306) at org.apache.flink.runtime.rpc.akka.AkkaRpcActor.handleRpcMessage(AkkaRpcActor.java:213) at org.apache.flink.runtime.rpc.akka.FencedAkkaRpcActor.handleRpcMessage(FencedAkkaRpcActor.java:77) at org.apache.flink.runtime.rpc.akka.AkkaRpcActor.handleMessage(AkkaRpcActor.java:159) at akka.japi.pf.UnitCaseStatement.apply(CaseStatements.scala:26) at akka.japi.pf.UnitCaseStatement.apply(CaseStatements.scala:21) at scala.PartialFunction.applyOrElse(PartialFunction.scala:123) at scala.PartialFunction.applyOrElse$(PartialFunction.scala:122) at akka.japi.pf.UnitCaseStatement.applyOrElse(CaseStatements.scala:21) at scala.PartialFunction$OrElse.applyOrElse(PartialFunction.scala:171) at scala.PartialFunction$OrElse.applyOrElse(PartialFunction.scala:172) at scala.PartialFunction$OrElse.applyOrElse(PartialFunction.scala:172) at akka.actor.Actor.aroundReceive(Actor.scala:517) at akka.actor.Actor.aroundReceive$(Actor.scala:515) at akka.actor.AbstractActor.aroundReceive(AbstractActor.scala:225) at akka.actor.ActorCell.receiveMessage(ActorCell.scala:592) at akka.actor.ActorCell.invoke(ActorCell.scala:561) at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:258) at akka.dispatch.Mailbox.run(Mailbox.scala:225) at akka.dispatch.Mailbox.exec(Mailbox.scala:235) ... 4 more Caused by: org.apache.flink.statefun.flink.core.functions.StatefulFunctionInvocationException: An error occurred when attempting to invoke function FunctionType(com.me.try, echo_user_id). at org.apache.flink.statefun.flink.core.functions.StatefulFunction.receive(StatefulFunction.java:50) at org.apache.flink.statefun.flink.core.functions.ReusableContext.apply(ReusableContext.java:73) at org.apache.flink.statefun.flink.core.functions.FunctionActivation.applyNextPendingEnvelope(FunctionActivation.java:50) at org.apache.flink.statefun.flink.core.functions.LocalFunctionGroup.processNextEnvelope(LocalFunctionGroup.java:61) at org.apache.flink.statefun.flink.core.functions.Reductions.processEnvelopes(Reductions.java:161) at org.apache.flink.statefun.flink.core.functions.Reductions.apply(Reductions.java:146) at org.apache.flink.statefun.flink.core.functions.FunctionGroupOperator.processElement(FunctionGroupOperator.java:90) at org.apache.flink.streaming.runtime.tasks.CopyingChainingOutput.pushToOperator(CopyingChainingOutput.java:71) at org.apache.flink.streaming.runtime.tasks.CopyingChainingOutput.collect(CopyingChainingOutput.java:46) at org.apache.flink.streaming.runtime.tasks.CopyingChainingOutput.collect(CopyingChainingOutput.java:26) at org.apache.flink.streaming.api.operators.CountingOutput.collect(CountingOutput.java:50) at org.apache.flink.streaming.api.operators.CountingOutput.collect(CountingOutput.java:28) at org.apache.flink.statefun.flink.core.feedback.FeedbackUnionOperator.sendDownstream(FeedbackUnionOperator.java:186) at org.apache.flink.statefun.flink.core.feedback.FeedbackUnionOperator.processElement(FeedbackUnionOperator.java:86) at org.apache.flink.streaming.runtime.tasks.OneInputStreamTask$StreamTaskNetworkOutput.emitRecord(OneInputStreamTask.java:187) at org.apache.flink.streaming.runtime.io.StreamTaskNetworkInput.processElement(StreamTaskNetworkInput.java:204) at org.apache.flink.streaming.runtime.io.StreamTaskNetworkInput.emitNext(StreamTaskNetworkInput.java:174) at org.apache.flink.streaming.runtime.io.StreamOneInputProcessor.processInput(StreamOneInputProcessor.java:65) at org.apache.flink.streaming.runtime.tasks.StreamTask.processInput(StreamTask.java:395) at org.apache.flink.streaming.runtime.tasks.mailbox.MailboxProcessor.runMailboxLoop(MailboxProcessor.java:191) at org.apache.flink.streaming.runtime.tasks.StreamTask.runMailboxLoop(StreamTask.java:609) at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:573) at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:755) at org.apache.flink.runtime.taskmanager.Task.run(Task.java:570) at java.base/java.lang.Thread.run(Thread.java:834) Caused by: java.lang.ClassCastException: class com.lambda.User cannot be cast to class org.apache.flink.statefun.sdk.reqreply.generated.TypedValue (com.lambda.User and org.apache.flink.statefun.sdk.reqreply.generated.TypedValue are in unnamed module of loader 'app') at org.apache.flink.statefun.flink.core.reqreply.RequestReplyFunction.invoke(RequestReplyFunction.java:90) at org.apache.flink.statefun.flink.core.functions.StatefulFunction.receive(StatefulFunction.java:48) ... 24 more Process finished with exit code 1 


      According to the above exception, it appears that the object being
      sent is a plain User, which is not a TypedValue, while I was
      expecting that the first map operator used to define the
      userIngress stream should suffice to correctly set-up the data to
      be sent to the stateful function. Can you spot something I am
      doing wrong?

    


    

    
Waiting for a kind reply,

    
Best regards

    


    

    
Dario Bonino

      
-- 
Ing. Dario Bonino, Ph.D

e-m@il: [hidden email] 
www: https://www.linkedin.com/in/dariobonino
<foaf:Person>
	<foaf:firstName>Dario</foaf:firstName>
	<foaf:surname>Bonino</foaf:surname>
	<foaf:msnChatID>[hidden email]</foaf:msnChatID>
</foaf:Person> 


      

  






	
	
	
				

			

		

			
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