Apache Avro Array of Array of Records fails in Python (“unhashable type, dict”) when loading schema

Question

All, I've had luck creating an Apache Avro schema with an array of records, but when I then try to make an array of an array of records, the python schema parser fails. Am I doing something wrong, or is this a bug?

    {
    "type": "record",
    "name": "userInfo",
    "namespace": "my.example",
    "fields": [
        {
            "name": "ID",
            "type": "string",
            "default": "NONE"
        },
        {
            "name": "message_timestamp",
            "type": "long"
        },
        {
            "name": "location",
            "type": [
                "null",
                "string"
            ],
            "default": "NONE"
        },
        {
            "name": "AttributeMapping0",
            "type": {
                "type": "array",
                "items": [
                    {
                        "name": "timestamp",
                        "type": "long"
                    },
                    {
                        "name": "AttributeMapping1",
                        "type": {
                            "type": "array",
                            "items": [
                                {
                                    "name": "AttributeMapping2",
                                    "type": "record",
                                    "fields": [
                                        {
                                            "name": "Name",
                                            "type": "string"
                                        },
                                        {
                                            "name": "Value",
                                            "type": "long"
                                        }
                                    ]
                                }
                            ]
                        }
                    }
                ]
            }
        }
    ]
}

The error message is very long - sorry:

      File "/usr/local/lib/python3.4/dist-packages/avro_python3-1.8.0-py3.4.egg/avro/schema.py", line 1283, in Parse
    return SchemaFromJSONData(json_data, names)
  File "/usr/local/lib/python3.4/dist-packages/avro_python3-1.8.0-py3.4.egg/avro/schema.py", line 1254, in SchemaFromJSONData
    return parser(json_data, names=names)
  File "/usr/local/lib/python3.4/dist-packages/avro_python3-1.8.0-py3.4.egg/avro/schema.py", line 1182, in _SchemaFromJSONObject
    other_props=other_props,
  File "/usr/local/lib/python3.4/dist-packages/avro_python3-1.8.0-py3.4.egg/avro/schema.py", line 1061, in __init__
    fields = make_fields(names=nested_names)
  File "/usr/local/lib/python3.4/dist-packages/avro_python3-1.8.0-py3.4.egg/avro/schema.py", line 1173, in MakeFields
    return tuple(RecordSchema._MakeFieldList(field_desc_list, names))
  File "/usr/local/lib/python3.4/dist-packages/avro_python3-1.8.0-py3.4.egg/avro/schema.py", line 986, in _MakeFieldList
    yield RecordSchema._MakeField(index, field_desc, names)
  File "/usr/local/lib/python3.4/dist-packages/avro_python3-1.8.0-py3.4.egg/avro/schema.py", line 957, in _MakeField
    names=names,
  File "/usr/local/lib/python3.4/dist-packages/avro_python3-1.8.0-py3.4.egg/avro/schema.py", line 1254, in SchemaFromJSONData
    return parser(json_data, names=names)
  File "/usr/local/lib/python3.4/dist-packages/avro_python3-1.8.0-py3.4.egg/avro/schema.py", line 1197, in _SchemaFromJSONObject
    items=SchemaFromJSONData(items_desc, names),
  File "/usr/local/lib/python3.4/dist-packages/avro_python3-1.8.0-py3.4.egg/avro/schema.py", line 1254, in SchemaFromJSONData
    return parser(json_data, names=names)
  File "/usr/local/lib/python3.4/dist-packages/avro_python3-1.8.0-py3.4.egg/avro/schema.py", line 1142, in _SchemaFromJSONArray
    return UnionSchema(map(MakeSchema, json_array))
  File "/usr/local/lib/python3.4/dist-packages/avro_python3-1.8.0-py3.4.egg/avro/schema.py", line 866, in __init__
    self._schemas = tuple(schemas)
  File "/usr/local/lib/python3.4/dist-packages/avro_python3-1.8.0-py3.4.egg/avro/schema.py", line 1141, in MakeSchema
    return SchemaFromJSONData(json_data=desc, names=names)
  File "/usr/local/lib/python3.4/dist-packages/avro_python3-1.8.0-py3.4.egg/avro/schema.py", line 1254, in SchemaFromJSONData
    return parser(json_data, names=names)
  File "/usr/local/lib/python3.4/dist-packages/avro_python3-1.8.0-py3.4.egg/avro/schema.py", line 1154, in _SchemaFromJSONObject
    if type in PRIMITIVE_TYPES:
TypeError: unhashable type: 'dict'

Any guidance would be much appreciated. Thanks.

Answer 1

Okay, so honestly I'm still not particularly sure on why the schema above fails, but this answer was what I was looking for: How to define avro schema for complex json document?

This answer here shows how to have an array of arrays of records. Just what I needed in my particular case.