Both the Confluent Avro Converter and the Confluent Avro Serializer use the Schema Registry. The reason is, as Tommy Becker mentioned below, to avoid storing the entire schema in each record (which the JSON serializer in Apache Kafka does). It has few other benefits schema validation and such.
If you are interested in trying this approach, you will want to use the Converter, since it was written specifically to integrate with Connect. If you prefer another approach, without the Schema Registry, you can write your own Converter - that's why we made them pluggable. Feel free to copy ours and modify it as fits your Avro approach. Gwen On Wed, Nov 2, 2016 at 2:48 AM, <david.frank...@bt.com> wrote: > I am using Kafka Connect in source mode i.e. using it to send events to > Kafka topics. > > With the key.converter and value.converter properties set to > org.apache.kafka.connect.storage.StringConverter I can attach a consumer > to the topics and see the events in a readable form. This is helpful and > reassuring but it is not the desired representation for my downstream > consumers - these require the events to be Avro encoded. > > It seems that to write the events to Kafka Avro encoded, these properties > need to be set to io.confluent.kafka.serializers.KafkaAvroSerializer. Is > this correct? > > I am not using the Confluent platform, merely the standard Kafka 10 > download, and have been unable to find out how to get at these from a Maven > repository jar. http://docs.confluent.io/3.0.0/app-development.html#java > suggest that these are available via: > > <dependency> > <groupId>io.confluent</groupId> > <artifactId>kafka-avro-serializer</artifactId> > <version>3.0.0</version> > </dependency> > > But it doesn't appear to be true. The class exists in > https://raw.githubusercontent.com/confluentinc/schema- > registry/master/avro-converter/src/main/java/io/confluent/connect/avro/ > AvroConverter.java but this seems to use the Schema Registry which is > something I'd rather avoid. > > I'd be grateful for any pointers on the simplest way of getting Avro > encoded events written to Kafka from a Kafka Connect source connector/task. > > Also in the task which creates SourceRecords, I'm choosing > Schema.BYTES_SCHEMA for the 4th arg in the constructor. But I'm not clear > what this achieves - some light shed on that would also be helpful. > > Many thanks, > David > -- *Gwen Shapira* Product Manager | Confluent 650.450.2760 | @gwenshap Follow us: Twitter <https://twitter.com/ConfluentInc> | blog <http://www.confluent.io/blog>
