kafka-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Manikumar Reddy <ku...@nmsworks.co.in>
Subject Re: [DISCUSSION] adding the serializer api back to the new java producer
Date Tue, 25 Nov 2014 16:29:03 GMT
+1 for this change.

what about de-serializer  class in 0.8.2?  Say i am using new producer with
Avro and old consumer combination.
then i need to give custom Decoder implementation for Avro right?.

On Tue, Nov 25, 2014 at 9:19 PM, Joe Stein <joe.stein@stealth.ly> wrote:

> The serializer is an expected use of the producer/consumer now and think we
> should continue that support in the new client. As far as breaking the API
> it is why we released the 0.8.2-beta to help get through just these type of
> blocking issues in a way that the community at large could be involved in
> easier with a build/binaries to download and use from maven also.
>
> +1 on the change now prior to the 0.8.2 release.
>
> - Joe Stein
>
>
> On Mon, Nov 24, 2014 at 11:43 PM, Sriram Subramanian <
> srsubramanian@linkedin.com.invalid> wrote:
>
> > Looked at the patch. +1 from me.
> >
> > On 11/24/14 8:29 PM, "Gwen Shapira" <gshapira@cloudera.com> wrote:
> >
> > >As one of the people who spent too much time building Avro repositories,
> > >+1
> > >on bringing serializer API back.
> > >
> > >I think it will make the new producer easier to work with.
> > >
> > >Gwen
> > >
> > >On Mon, Nov 24, 2014 at 6:13 PM, Jay Kreps <jay.kreps@gmail.com> wrote:
> > >
> > >> This is admittedly late in the release cycle to make a change. To add
> to
> > >> Jun's description the motivation was that we felt it would be better
> to
> > >> change that interface now rather than after the release if it needed
> to
> > >> change.
> > >>
> > >> The motivation for wanting to make a change was the ability to really
> be
> > >> able to develop support for Avro and other serialization formats. The
> > >> current status is pretty scattered--there is a schema repository on an
> > >>Avro
> > >> JIRA and another fork of that on github, and a bunch of people we have
> > >> talked to have done similar things for other serialization systems. It
> > >> would be nice if these things could be packaged in such a way that it
> > >>was
> > >> possible to just change a few configs in the producer and get rich
> > >>metadata
> > >> support for messages.
> > >>
> > >> As we were thinking this through we realized that the new api we were
> > >>about
> > >> to introduce was kind of not very compatable with this since it was
> just
> > >> byte[] oriented.
> > >>
> > >> You can always do this by adding some kind of wrapper api that wraps
> the
> > >> producer. But this puts us back in the position of trying to document
> > >>and
> > >> support multiple interfaces.
> > >>
> > >> This also opens up the possibility of adding a MessageValidator or
> > >> MessageInterceptor plug-in transparently so that you can do other
> custom
> > >> validation on the messages you are sending which obviously requires
> > >>access
> > >> to the original object not the byte array.
> > >>
> > >> This api doesn't prevent using byte[] by configuring the
> > >> ByteArraySerializer it works as it currently does.
> > >>
> > >> -Jay
> > >>
> > >> On Mon, Nov 24, 2014 at 5:58 PM, Jun Rao <junrao@gmail.com> wrote:
> > >>
> > >> > Hi, Everyone,
> > >> >
> > >> > I'd like to start a discussion on whether it makes sense to add the
> > >> > serializer api back to the new java producer. Currently, the new
> java
> > >> > producer takes a byte array for both the key and the value. While
> this
> > >> api
> > >> > is simple, it pushes the serialization logic into the application.
> > >>This
> > >> > makes it hard to reason about what type of data is being sent to
> Kafka
> > >> and
> > >> > also makes it hard to share an implementation of the serializer. For
> > >> > example, to support Avro, the serialization logic could be quite
> > >>involved
> > >> > since it might need to register the Avro schema in some remote
> > >>registry
> > >> and
> > >> > maintain a schema cache locally, etc. Without a serialization api,
> > >>it's
> > >> > impossible to share such an implementation so that people can easily
> > >> reuse.
> > >> > We sort of overlooked this implication during the initial discussion
> > >>of
> > >> the
> > >> > producer api.
> > >> >
> > >> > So, I'd like to propose an api change to the new producer by adding
> > >>back
> > >> > the serializer api similar to what we had in the old producer.
> > >>Specially,
> > >> > the proposed api changes are the following.
> > >> >
> > >> > First, we change KafkaProducer to take generic types K and V for the
> > >>key
> > >> > and the value, respectively.
> > >> >
> > >> > public class KafkaProducer<K,V> implements Producer<K,V>
{
> > >> >
> > >> >     public Future<RecordMetadata> send(ProducerRecord<K,V>
record,
> > >> Callback
> > >> > callback);
> > >> >
> > >> >     public Future<RecordMetadata> send(ProducerRecord<K,V>
record);
> > >> > }
> > >> >
> > >> > Second, we add two new configs, one for the key serializer and
> another
> > >> for
> > >> > the value serializer. Both serializers will default to the byte
> array
> > >> > implementation.
> > >> >
> > >> > public class ProducerConfig extends AbstractConfig {
> > >> >
> > >> >     .define(KEY_SERIALIZER_CLASS_CONFIG, Type.CLASS,
> > >> > "org.apache.kafka.clients.producer.ByteArraySerializer",
> > >>Importance.HIGH,
> > >> > KEY_SERIALIZER_CLASS_DOC)
> > >> >     .define(VALUE_SERIALIZER_CLASS_CONFIG, Type.CLASS,
> > >> > "org.apache.kafka.clients.producer.ByteArraySerializer",
> > >>Importance.HIGH,
> > >> > VALUE_SERIALIZER_CLASS_DOC);
> > >> > }
> > >> >
> > >> > Both serializers will implement the following interface.
> > >> >
> > >> > public interface Serializer<T> extends Configurable {
> > >> >     public byte[] serialize(String topic, T data, boolean isKey);
> > >> >
> > >> >     public void close();
> > >> > }
> > >> >
> > >> > This is more or less the same as what's in the old producer. The
> > >>slight
> > >> > differences are (1) the serializer now only requires a
> parameter-less
> > >> > constructor; (2) the serializer has a configure() and a close()
> method
> > >> for
> > >> > initialization and cleanup, respectively; (3) the serialize() method
> > >> > additionally takes the topic and an isKey indicator, both of which
> are
> > >> > useful for things like schema registration.
> > >> >
> > >> > The detailed changes are included in KAFKA-1797. For completeness,
I
> > >>also
> > >> > made the corresponding changes for the new java consumer api as
> well.
> > >> >
> > >> > Note that the proposed api changes are incompatible with what's in
> the
> > >> > 0.8.2 branch. However, if those api changes are beneficial, it's
> > >>probably
> > >> > better to include them now in the 0.8.2 release, rather than later.
> > >> >
> > >> > I'd like to discuss mainly two things in this thread.
> > >> > 1. Do people feel that the proposed api changes are reasonable?
> > >> > 2. Are there any concerns of including the api changes in the 0.8.2
> > >>final
> > >> > release?
> > >> >
> > >> > Thanks,
> > >> >
> > >> > Jun
> > >> >
> > >>
> >
> >
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message