The tuple is Heron‘s core data type. Heron’s native Tuple interface supports a broad range of basic data types, such as strings, integers, and booleans, out of the box, but tuples can contain values of any type. You can use data types beyond the core types by providing a custom serializer using the instructions below.
Heron uses Kryo for tuple serialization and deserialization. You can create a custom tuple serializer by extending Kryo's abstract Serializer class. More information can be found in Kryo's documentation.
Once you've created a custom Kryo serializer for a type:
topology.kryo.register parameter for your topology. Here's an example:topology.kryo.register: - biz.acme.heron.datatypes.CustomType1 # This type will use the default FieldSerializer - biz.acme.heron.datatypes.CustomType2: com.example.heron.serialization.CustomSerializer
Once your custom serializer is on Heron's classpath and Heron is aware of its existence, you must re-compile Heron.