How can I reference JSONSchema?

[timonviola]

Hi

How can I reference JSONSchemas (registered data contracts) with the oneOf keyword?

I am stuck with trying to reference multiple JSONSchemas in on topic using oneOf keyword. I tried to follow this example: https://www.confluent.io/blog/multiple-event-types-in-the-same-kafka-topic/

however, the given example is invalid:

{
  "oneOf": [
     { "$ref": "Customer.schema.json" },
     { "$ref": "Product.schema.json" },
     { "$ref": "Order.schema.json }
  ]
}

I tried to use my data with this schema:

{
  "$id": "http://example.com/oneof.schema.json",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "additionalProperties": false,
  "description": "Sample schema to help you get started.",
  "oneOf": [
    {
      "$ref": "http://example.com/lunch"
    },
    {
      "$ref": "http://example.com/snow"
    }
  ],
  "title": "oneof",
  "type": "object"
}

I also tried wrapping the "oneOf" object into properties, but alas, no success.

The dummy reference (works as expected):

{
  "$id": "http://example.com/lunch.schema.json",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "additionalProperties": false,
  "description": "Sample schema to help you get started.",
  "properties": {
    "lunch": {
      "description": "The string type is used for strings of text.",
      "type": "string"
    }
  },
  "title": "lunch",
  "type": "object"
}

The response I get from SchemaRegistry:

{
    "subject": "schema-registry.oneof-value",
    "version": 1,
    "id": 100222,
    "schemaType": "JSON",
    "references": [
        {
            "name": "http://example.com/lunch",
            "subject": "pub.schema-registry-poc-usafo.lunch-sux",
            "version": 1
        },
        {
            "name": "http://example.com/snow",
            "subject": "pub.schema-registry-poc-usafo.snow-value",
            "version": 2
        }
    ],
    "schema": "{\"$id\":\"http://example.com/oneof.schema.json\",\"$schema\":\"http://json-schema.org/draft-07/schema#\",\"additionalProperties\":false,\"description\":\"Sample schema to help you get started.\",\"oneOf\":[{\"$ref\":\"http://example.com/lunch\"},{\"$ref\":\"http://example.com/snow\"}],\"title\":\"oneof\",\"type\":\"object\"}"
}