Add version to every schema

[fnobilia]

In Avro it is possible to add version at schema level

{
  "namespace": "org.radarcns.kafka.key",
  "type": "record",
  "name": "KeyMeasurement",
  "doc": "Measurement key in the RADAR-CNS project.",
  "fields": [
    {"name": "userId", "type": "string", "doc": "User Identifier created during the enrolment."},
    {"name": "sourceId", "type": "string", "doc": "Unique identifier associated with the source."}
  ],
  "version": "1.0"
}

The version property can then be accessed using

KeyMeasurement.getClassSchema().getObjectProps().get("version")

I am not sure if adding a version property at schema level will only complicate the maintainability or it is a good enhancement. We can track the version of each schema within the library, but we need to be more carful while committing a new version.

@blootsvoets @mbegalevibrent what do you think?

[fnobilia]

Another though, using version

• we can easily understand what schemas are stored in the schema registry just checking the version property
• it could useful while troubleshooting