By the way, could you you try just using KafkaIO.Read. This is the the
official Beam Kafka source and it should work well with the Flink runner.
On Thu, 2 Jun 2016 at 22:47 Viswadeep <[email protected]> wrote:

> yes!, i have tried it works.
> -Viswadeep
>
> Viswadeep Veguru.
>
>
> On Thu, Jun 2, 2016 at 12:43 PM, Amit Sela <[email protected]> wrote:
>
>> I'm not too familiar with Flink but is there a way to simply read bytes
>> of Kafka and in the next step (map ?) to Deserialize the bytes that
>> represent this object and transform it into a "Kryo-compliant" object ?
>> This should avoid Kryo, right ?
>>
>> On Thu, Jun 2, 2016 at 10:31 PM Viswadeep <[email protected]> wrote:
>>
>>> Hi Max,
>>>
>>> I tried your approach (1) it did not work. I am still getting the same
>>> exception.
>>> (2) is not possible, unless protobuff complier changes.
>>>
>>> Yes setting that in config also did not work as well.
>>>
>>> I think some where inside flink it is not able to process correctly.
>>>
>>>
>>> Thanks
>>> Viswadeep
>>>
>>>
>>> Viswadeep Veguru.
>>>
>>>
>>> On Thu, Jun 2, 2016 at 10:09 AM, Maximilian Michels <[email protected]>
>>> wrote:
>>>
>>>> Hi Viswadeep,
>>>>
>>>> What Amit recommended (thanks!) is indeed an easy fix if you're using
>>>> Flink. However, we don't expose the ExecutionConfig in Beam. So
>>>> setting custom Kryo serializers is not possible.
>>>>
>>>> Two other options I see:
>>>>
>>>> 1) Could you try using the following in your deserialization schema?
>>>>
>>>>    @Override
>>>>     public TypeInformation<T> getProducedType() {
>>>>         return new CoderTypeInformation<>(coder);
>>>>     }
>>>>
>>>> 2) Could you avoid using Collections.UnmodifiableList in your code?
>>>> Not sure if it is possible because it seems to be a field in your
>>>> Protobuf class.
>>>>
>>>> Thanks,
>>>> Max
>>>>
>>>> On Thu, Jun 2, 2016 at 4:49 PM, Viswadeep <[email protected]> wrote:
>>>> > Thanks Amit,
>>>> >
>>>> > It did not solve my issue, Flink it self has the following comment in
>>>> > ExecutionConfig.java
>>>> >
>>>> > /**
>>>> >  * Force TypeExtractor to use Kryo serializer for POJOS even though
>>>> we could
>>>> > analyze as POJO.
>>>> >  * In some cases this might be preferable. For example, when using
>>>> > interfaces
>>>> >  * with subclasses that cannot be analyzed as POJO.
>>>> >  */
>>>> >
>>>> >
>>>> > Because generated Protobuf class extends GeneratedMessage implements
>>>> > Employee.PacketOrBuilder
>>>> >
>>>> >
>>>> > Thanks for any help.
>>>> > Viswadeep
>>>> >
>>>> >
>>>> > On Wed, Jun 1, 2016 at 11:02 PM, Amit Sela <[email protected]>
>>>> wrote:
>>>> >>
>>>> >> I think it has to do with Flink's internal use of Kryo  - take a
>>>> look at
>>>> >> this:
>>>> >>
>>>> http://stackoverflow.com/questions/32453030/using-an-collectionsunmodifiablecollection-with-apache-flink
>>>> >> I'm sure Flink committers will soon reach out to correct me if I'm
>>>> missing
>>>> >> something..
>>>> >>
>>>> >> On Thu, Jun 2, 2016 at 5:01 AM Viswadeep <[email protected]>
>>>> wrote:
>>>> >>>
>>>> >>> Hi
>>>> >>>
>>>> >>> I am using apache beam with flink and ProtoBuf for encoding and
>>>> decoding.
>>>> >>>
>>>> >>> The following is the method for the FlinkKafka Consumer.
>>>> >>>
>>>> >>> public UnboundedSource<T extends
>>>> Message,UnboundedSource.CheckpointMark>
>>>> >>> build() {
>>>> >>>     Properties p = new Properties();
>>>> >>>     p.setProperty("zookeeper.connect", kafkaOptions.getZookeeper());
>>>> >>>     p.setProperty("bootstrap.servers", kafkaOptions.getBroker());
>>>> >>>     p.setProperty("group.id", kafkaOptions.getGroup());
>>>> >>>     FlinkKafkaConsumer09<T> kafkaConsumer = new
>>>> >>> FlinkKafkaConsumer09<>(kafkaOptions.getKafkaTopic(),
>>>> >>>             new SerializationDeserializationSchema(typedSource,
>>>> >>> ProtoCoder.of(typedSource)), p);
>>>> >>>     return UnboundedFlinkSource.of(kafkaConsumer);
>>>> >>> }
>>>> >>>
>>>> >>> and the helper for serialization and DeSerialization is this.
>>>> >>>
>>>> >>> public class SerializationDeserializationSchema<T>
>>>> >>>         implements SerializationSchema<T>, DeserializationSchema<T>
>>>> {
>>>> >>>
>>>> >>>     private final Class<T> tClass;
>>>> >>>
>>>> >>>     private final Coder<T> coder;
>>>> >>>     private transient ByteArrayOutputStream out;
>>>> >>>
>>>> >>>     public SerializationDeserializationSchema(Class<T> clazz,
>>>> Coder<T>
>>>> >>> coder) {
>>>> >>>         this.tClass = clazz;
>>>> >>>         this.coder = coder;
>>>> >>>         this.out = new ByteArrayOutputStream();
>>>> >>>     }
>>>> >>>
>>>> >>>     @Override
>>>> >>>     public byte[] serialize(T element) {
>>>> >>>
>>>> >>>         if (out == null) {
>>>> >>>             out = new ByteArrayOutputStream();
>>>> >>>         }
>>>> >>>         try {
>>>> >>>             out.reset();
>>>> >>>             coder.encode(element, out, Coder.Context.NESTED);
>>>> >>>         } catch (IOException e) {
>>>> >>>             throw new RuntimeException("encoding failed.", e);
>>>> >>>         }
>>>> >>>         return out.toByteArray();
>>>> >>>     }
>>>> >>>
>>>> >>>     @Override
>>>> >>>     public T deserialize(byte[] message) throws IOException {
>>>> >>>         return coder.decode(new ByteArrayInputStream(message),
>>>> >>> Coder.Context.NESTED);
>>>> >>>     }
>>>> >>>
>>>> >>>     @Override
>>>> >>>     public boolean isEndOfStream(T nextElement) {
>>>> >>>         return false;
>>>> >>>     }
>>>> >>>
>>>> >>>     @Override
>>>> >>>     public TypeInformation<T> getProducedType() {
>>>> >>>         return TypeExtractor.getForClass(tClass);
>>>> >>>     }
>>>> >>> }
>>>> >>>
>>>> >>>
>>>> >>> I am getting the following, Kyro exception.
>>>> >>>
>>>> >>> java.lang.RuntimeException: ConsumerThread threw an exception:
>>>> Could not
>>>> >>> forward element to next operator
>>>> >>>         at
>>>> >>>
>>>> org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer09.run(FlinkKafkaConsumer09.java:336)
>>>> >>>         at
>>>> >>>
>>>> org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:78)
>>>> >>>         at
>>>> >>>
>>>> org.apache.flink.streaming.runtime.tasks.SourceStreamTask.run(SourceStreamTask.java:56)
>>>> >>>         at
>>>> >>>
>>>> org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:225)
>>>> >>>         at
>>>> org.apache.flink.runtime.taskmanager.Task.run(Task.java:559)
>>>> >>>         at java.lang.Thread.run(Thread.java:745)
>>>> >>>     Caused by: java.lang.RuntimeException: Could not forward
>>>> element to
>>>> >>> next operator
>>>> >>>         at
>>>> >>>
>>>> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:354)
>>>> >>>         at
>>>> >>>
>>>> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:337)
>>>> >>>         at
>>>> >>>
>>>> org.apache.flink.streaming.api.operators.StreamSource$ManualWatermarkContext.collect(StreamSource.java:318)
>>>> >>>         at
>>>> >>>
>>>> org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer09$ConsumerThread.run(FlinkKafkaConsumer09.java:473)
>>>> >>>     Caused by: com.esotericsoftware.kryo.KryoException:
>>>> >>> java.lang.UnsupportedOperationException
>>>> >>>     Serialization trace:
>>>> >>>     records_ (com.model.Employee$Packet)
>>>> >>>         at
>>>> >>>
>>>> com.esotericsoftware.kryo.serializers.ObjectField.read(ObjectField.java:125)
>>>> >>>         at
>>>> >>>
>>>> com.esotericsoftware.kryo.serializers.FieldSerializer.read(FieldSerializer.java:528)
>>>> >>>         at com.esotericsoftware.kryo.Kryo.readObject(Kryo.java:657)
>>>> >>>         at
>>>> >>>
>>>> org.apache.flink.api.java.typeutils.runtime.kryo.KryoSerializer.copy(KryoSerializer.java:168)
>>>> >>>         at
>>>> >>>
>>>> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:349)
>>>> >>>         ... 3 more
>>>> >>>     Caused by: java.lang.UnsupportedOperationException
>>>> >>>         at
>>>> >>>
>>>> java.util.Collections$UnmodifiableCollection.add(Collections.java:1055)
>>>> >>>         at
>>>> >>>
>>>> com.esotericsoftware.kryo.serializers.CollectionSerializer.read(CollectionSerializer.java:116)
>>>> >>>         at
>>>> >>>
>>>> com.esotericsoftware.kryo.serializers.CollectionSerializer.read(CollectionSerializer.java:22)
>>>> >>>         at com.esotericsoftware.kryo.Kryo.readObject(Kryo.java:679)
>>>> >>>         at
>>>> >>>
>>>> com.esotericsoftware.kryo.serializers.ObjectField.read(ObjectField.java:106)
>>>> >>>
>>>> >>>
>>>> >>> I am not able to avoid this "Kryo" Exception, Thanks for any help.
>>>> >>>
>>>> >>> Thanks
>>>> >>>
>>>> >>> Viswadeep.
>>>> >>>
>>>> >
>>>> >
>>>>
>>>
>>>
>

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