Integers in output_sample cause TypeError

[csiebler]

We're using the following input and output sample with latest inference-schema version:

input_sample = [{​​
  'YEAR': 2020,
  'MONTH': 1,
  'DAY_OF_MONTH': 19,
  'OP_UNIQUE_CARRIER': 'DL',
  'ORIGIN_AIRPORT_ID': 13487,
  'ORIGIN_CITY_NAME': 'Minneapolis, MN',
  'DEST_AIRPORT_ID': 14635,
  'DEST_CITY_NAME': 'Fort Myers, FL',
  'DEP_DELAY': 0,
  'ARR_DELAY': -3,
  'CANCELLED': 0,
  'AIR_TIME': 20,
  'FLIGHTS': 1,
  'DISTANCE': 141
}​​]
output_sample = [[1, 2, 0, 0, 0]]

The decorator for the run method in score.py looks like this:

@input_schema('data', StandardPythonParameterType(input_sample))
@output_schema(StandardPythonParameterType(output_sample))
def run(data):
  ...

However, when we deploy the model in AML and call the API, it fails with the following message:

2021-01-12 09:39:50,919 | root | ERROR | Encountered Exception: Traceback (most recent call last):
  File "/azureml-envs/azureml_837afcc2e08970eb06ca005e02218b03/lib/python3.6/site-packages/flask/app.py", line 1832, in full_dispatch_request
    rv = self.dispatch_request()
  File "/azureml-envs/azureml_837afcc2e08970eb06ca005e02218b03/lib/python3.6/site-packages/flask/app.py", line 1818, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/var/azureml-server/app.py", line 142, in score_realtime
    return run_scoring(service_input, request.headers, request.environ.get('REQUEST_ID', '00000000-0000-0000-0000-000000000000'))
  File "/var/azureml-server/app.py", line 274, in run_scoring
    return AMLResponse(response_body, response_status_code, response_headers, json_str=True)
  File "/var/azureml-server/azureml/contrib/services/aml_response.py", line 16, in __init__
    super().__init__(json.dumps(message), status=status_code, mimetype='application/json')
  File "/azureml-envs/azureml_837afcc2e08970eb06ca005e02218b03/lib/python3.6/json/__init__.py", line 231, in dumps
    return _default_encoder.encode(obj)
  File "/azureml-envs/azureml_837afcc2e08970eb06ca005e02218b03/lib/python3.6/json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/azureml-envs/azureml_837afcc2e08970eb06ca005e02218b03/lib/python3.6/json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
  File "/azureml-envs/azureml_837afcc2e08970eb06ca005e02218b03/lib/python3.6/json/encoder.py", line 180, in default
    o.__class__.__name__)
TypeError: Object of type 'int64' is not JSON serializable

When we change output_sample = [[1, 2, 0, 0, 0]] to output_sample = [[1.0, 2.0, 0.0, 0.0, 0.0]] it works, so there seems to be some issues with Integers?

Would be great if this could be fixed. Any help is appreciated.

Thanks
Clemens