Flink Kafka EXACTLY_ONCE causing KafkaException ByteArraySerializer is not an instance of Serializer

Question

So, I'm trying to enable EXACTLY_ONCE semantic in my Flink Kafka streaming job along with checkpointing.

However I am not getting it to work, so I tried downloading the test sample code from Github: https://github.com/apache/flink/blob/c025407e8a11dff344b587324ed73bdba2024dff/flink-end-to-end-tests/flink-streaming-kafka-test/src/main/java/org/apache/flink/streaming/kafka/test/KafkaExample.java

So running this works fine. However, when enabling checkpointing I get errors. Or if I change EXACTLY_ONCE to AT_LEAST_ONCE semantics and enable checkpointing, it works fine. But then when changing it to EXACTLY_ONCE, I get this error again.

The exception I'm getting:

org.apache.kafka.common.KafkaException: org.apache.kafka.common.KafkaException: Failed to construct kafka producer
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at java.util.concurrent.ForkJoinTask.getThrowableException(ForkJoinTask.java:593)
    at java.util.concurrent.ForkJoinTask.reportException(ForkJoinTask.java:677)
    at java.util.concurrent.ForkJoinTask.invoke(ForkJoinTask.java:735)
    at java.util.stream.ForEachOps$ForEachOp.evaluateParallel(ForEachOps.java:159)
    at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateParallel(ForEachOps.java:173)
    at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:233)
    at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:485)
    at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:650)
    at org.apache.flink.streaming.connectors.kafka.FlinkKafkaProducer.abortTransactions(FlinkKafkaProducer.java:1099)
    at org.apache.flink.streaming.connectors.kafka.FlinkKafkaProducer.initializeState(FlinkKafkaProducer.java:1036)
    at org.apache.flink.streaming.util.functions.StreamingFunctionUtils.tryRestoreFunction(StreamingFunctionUtils.java:178)
    at org.apache.flink.streaming.util.functions.StreamingFunctionUtils.restoreFunctionState(StreamingFunctionUtils.java:160)
    at org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator.initializeState(AbstractUdfStreamOperator.java:96)
    at org.apache.flink.streaming.api.operators.AbstractStreamOperator.initializeState(AbstractStreamOperator.java:284)
    at org.apache.flink.streaming.runtime.tasks.StreamTask.initializeStateAndOpen(StreamTask.java:1006)
    at org.apache.flink.streaming.runtime.tasks.StreamTask.lambda$beforeInvoke$0(StreamTask.java:454)
    at org.apache.flink.streaming.runtime.tasks.StreamTaskActionExecutor$SynchronizedStreamTaskActionExecutor.runThrowing(StreamTaskActionExecutor.java:94)
    at org.apache.flink.streaming.runtime.tasks.StreamTask.beforeInvoke(StreamTask.java:449)
    at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:461)
    at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:707)
    at org.apache.flink.runtime.taskmanager.Task.run(Task.java:532)
    at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.kafka.common.KafkaException: Failed to construct kafka producer
    at org.apache.kafka.clients.producer.KafkaProducer.<init>(KafkaProducer.java:430)
    at org.apache.kafka.clients.producer.KafkaProducer.<init>(KafkaProducer.java:298)
    at org.apache.flink.streaming.connectors.kafka.internal.FlinkKafkaInternalProducer.<init>(FlinkKafkaInternalProducer.java:76)
    at org.apache.flink.streaming.connectors.kafka.FlinkKafkaProducer.lambda$abortTransactions$2(FlinkKafkaProducer.java:1107)
    at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
    at java.util.HashMap$KeySpliterator.forEachRemaining(HashMap.java:1556)
    at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482)
    at java.util.stream.ForEachOps$ForEachTask.compute(ForEachOps.java:290)
    at java.util.concurrent.CountedCompleter.exec(CountedCompleter.java:731)
    at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
    at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
    at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
    at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
Caused by: org.apache.kafka.common.KafkaException: org.apache.kafka.common.serialization.ByteArraySerializer is not an instance of org.apache.kafka.common.serialization.Serializer
    at org.apache.kafka.common.config.AbstractConfig.getConfiguredInstance(AbstractConfig.java:304)
    at org.apache.kafka.clients.producer.KafkaProducer.<init>(KafkaProducer.java:360)
    ... 12 more

I've made slight changes to the code to work in my enviroment. I'm running it inside the flink operations playground inside docker. (This https://ci.apache.org/projects/flink/flink-docs-stable/getting-started/docker-playgrounds/flink-operations-playground.html ). Latest version, 1.10 and the provided kafka inside that is verison 2.2.1

    public static void main(String[] args) throws Exception {

        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        env.enableCheckpointing(1_000);

        String inputTopic = "my-input";
        String outputTopic = "my-output";
        String kafkaHost = "kafka:9092";

        Properties kafkaProps = new Properties();
        kafkaProps.setProperty(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, kafkaHost);
        kafkaProps.setProperty(ConsumerConfig.GROUP_ID_CONFIG, "test");


        DataStream<KafkaEvent> input = env
                .addSource(new FlinkKafkaConsumer<>(inputTopic, new KafkaEventSchema(), kafkaProps)
                        .assignTimestampsAndWatermarks(new CustomWatermarkExtractor()))
                .keyBy("word")
                .map(new RollingAdditionMapper());

        input.addSink(
                new FlinkKafkaProducer<>(
                        outputTopic,
                        new KafkaEventSerializationSchema(outputTopic),
                        kafkaProps,
                        FlinkKafkaProducer.Semantic.EXACTLY_ONCE));

        env.execute("Modern Kafka Example");
    }

Other classes from the example can be found: https://github.com/apache/flink/tree/c025407e8a11dff344b587324ed73bdba2024dff/flink-end-to-end-tests/flink-streaming-kafka-test-base/src/main/java/org/apache/flink/streaming/kafka/test/base

I did try to change the serialization to use KafkaSerializationSchema rather than the example code which use SerializationSchema. However that code, below did not help either. Same error.

import org.apache.flink.streaming.connectors.kafka.KafkaSerializationSchema;
import org.apache.kafka.clients.producer.ProducerRecord;

public class KafkaEventSerializationSchema implements KafkaSerializationSchema<KafkaEvent> {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    private String topic;

    public KafkaEventSerializationSchema(String topic) {
        this.topic = topic;
    }

    @Override
    public ProducerRecord<byte[], byte[]> serialize(KafkaEvent element, Long timestamp) {
        return new ProducerRecord<>(topic, element.toString().getBytes());
    }


}

All help appreciated. I haven't been able to find any online working code of EXACTLY_ONCE garantuee between flink and kafka. Only loads articles talking about it but not actual substancial working code. That's all I'm trying to achieve here.

Answer 1

I ran into the same problem and explicitly setting a timeout for the producer helped. properties.setProperty("transaction.timeout.ms", "900000");