Is it possible to have an optional field in an Avro schema (i.e. the field does not appear at all in the .json file)?

[Emre Sevinc <em...@gmail.com>]

Is it possible to have an optional field in an Avro schema (i.e. the field
does not appear at all in the .JSON file)?

In my Avro schema, I have two fields:

  {"name": "author", "type": ["null", "string"], "default": null},
{"name": "importance", "type": ["null", "string"], "default": null},

And in my JSON files those two fields can exist or not.

However, when they do not exist, I receive an error (e.g. when I test such
a JSON file using avro-tools command line client):

  Expected field name not found: author

I understand that as long as the *field name* exists in a JSON, it can be
null, or a string value, but what I'm trying to express is something like
"this JSON is valid if the those field names *do not exist*, OR if they
exist and they are null or string".

Is this possible to express in an Avro schema? If so, how?
-- 
Emre Sevinç