DataStream<MyKafkaMessage> MyKafkaMessageDataStream = env.addSource(
getStreamSource(env, parameterTool);
);
public RichParallelSourceFunction<MyKafkaMessage>
getStreamSource(StreamExecutionEnvironment env, ParameterTool
parameterTool) {
// MyKAfkaMessage is a ProtoBuf message
env.getConfig().registerTypeWithKryoSerializer(MyKafkaMessage.class,
ProtobufSerializer.class);
KafkaDataSource<MyKafkaMessage> flinkCepConsumer =
new KafkaDataSource<MyKafkaMessage>(parameterTool, new
MyKafkaMessageSerDeSchema());
return flinkCepConsumer;
}
public class KafkaDataSource<T> extends FlinkKafkaConsumer010<T> {
public KafkaDataSource(ParameterTool parameterTool,
DeserializationSchema<T> deserializer) {
super(
Arrays.asList(parameterTool.getRequired("topic").split(",")),
deserializer,
parameterTool.getProperties()
);
}
}
public class MyKafkaMessageSerDeSchema implements
DeserializationSchema<MyKafkaMessage>, SerializationSchema<MyKafkaMessage> {
@Override
public MyKafkaMessage deserialize(byte[] message) throws IOException {
MyKafkaMessage MyKafkaMessage = null;
try {
MyKafkaMessage = MyKafkaMessage.parseFrom(message);
} catch (InvalidProtocolBufferException e) {
e.printStackTrace();
} finally {
return MyKafkaMessage;
}
}
@Override
public boolean isEndOfStream(MyKafkaMessage nextElement) {
return false;
}
@Override
public TypeInformation<MyKafkaMessage> getProducedType() {
return null;
}
@Override
public byte[] serialize(MyKafkaMessage element) {
return new byte[0];
}
}
On Mon, Aug 28, 2017 at 8:26 PM, Ted Yu <yuzhih...@gmail.com> wrote:
> Which version of Flink / Kafka are you using ?
>
> Can you show the snippet of code where you create the DataStream ?
>
> Cheers
>
> On Mon, Aug 28, 2017 at 7:38 AM, Sridhar Chellappa <flinken...@gmail.com>
> wrote:
>
>> Folks,
>>
>> I have a KafkaConsumer that I am trying to read messages from. When I try
>> to create a DataStream from the KafkConsumer (env.addSource()) I get the
>> following exception :
>>
>> Any idea on how can this happen?
>>
>> java.lang.NullPointerException
>> at
>> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.pushToOperator(OperatorChain.java:526)
>> at
>> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:503)
>> at
>> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:483)
>> at
>> org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:891)
>> at
>> org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:869)
>> at
>> org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collect(StreamSourceContexts.java:103)
>> at
>> org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collectWithTimestamp(StreamSourceContexts.java:110)
>> at
>> org.apache.flink.streaming.connectors.kafka.internals.AbstractFetcher.emitRecordWithTimestamp(AbstractFetcher.java:264)
>> at
>> org.apache.flink.streaming.connectors.kafka.internal.Kafka010Fetcher.emitRecord(Kafka010Fetcher.java:86)
>> at
>> org.apache.flink.streaming.connectors.kafka.internal.Kafka09Fetcher.runFetchLoop(Kafka09Fetcher.java:149)
>> at
>> org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumerBase.run(FlinkKafkaConsumerBase.java:449)
>> at
>> org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:87)
>> at
>> org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:55)
>> at
>> org.apache.flink.streaming.runtime.tasks.SourceStreamTask.run(SourceStreamTask.java:95)
>> at
>> org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:262)
>> at org.apache.flink.runtime.taskmanager.Task.run(Task.java:702)
>> at java.lang.Thread.run(Thread.java:748)
>>
>>
>
