Hi list, I'm working on a project in Java where we have a DSL working on GenericRecord objects, over which we define record transformation operations like projections, filters and so. This implies that the avro schema of the records evolves by adding and deleting record fields. As a result the avro schemas used are different in each program depending on the operations used. Hence I have to define avro schema transformations, and generate new schemas as modifications of other schemas. For that the avro schema builder classes are only useful for the starting schema, and so does a pojo to schema mapping like avro-jackson. The main problem I face is that in avro by design "schema objects are logically immutable", as stated in the documentation. So far I've taken the way of converting the schema to string, parsing it with jackson and manipulate it's representation as JsonNode, and then parsing it back to Avro. In that latter step I sometimes have problems because avro records are named, and anonymous records are not always legal in complete schemas; or because the same record name cannot be used twice in two child fields of a parent record. I was then thinking in using generated schema names, with an increasing ID or a random UUID. Anyway my question is, the approach I'm describing is correct?, are you aware of some library for creating new avro schemas by manipulating an input schema? Maybe that capabilities are already present in avro's Java API but I haven't noticed.
Any help with be welcome. Thanks a lot in advance Greetings, Juan Rodríguez Hortalá
