By   December 29, 2017

Building Serde for Kafka Streams Application

While developing Kafka Streams applications, I found myself requiring some utility code over and over. One such code is to build Serde for custom types. It is better if it is refactored into separate types and used when needed.

It has two methods specificAvroSerde and genericAvroSerde. It must be remembered that we need to specify if the created Serde will be used for Key or value through an argument to configure method. We are just exposing this through our methods to give more flexibility to the users of this utility type.

The SerdeBuilder can be used to build custom Serdes. Here we are using it for a custom Avro type SensorHeartbeat.

Now this Serde can be used for any serialization / deserialization. Here we are using for two different purposes. The first is for KStream’s to method, which is used to write the events to a new Kafka type. In this case, the Serde is being used specifically for serialization. In the other case, we are using it for groupBy. In this case, if we don’t provide a Serde, then the default Serde is picked for the KafkaStreams, which might not be what you need.