fix #234: Added method to fixup non json-spec compliant floats to mak…

…e the resp… (#236)

* Added method to fixup non json-spec compliant floats to make the response json compliant

src/gluonts/shell/serve.py

@@ -21,6 +21,7 @@
 
 # Third-party imports
 import requests
+import numpy as np
 from flask import Flask, Response, jsonify, request
 from gunicorn.app.base import BaseApplication
 from pydantic import BaseModel, BaseSettings
@@ -82,6 +83,31 @@ def log_throughput(instances, timings):
  # list(zip(timings, item_lengths)
 
 
+def jsonify_floats(json_object):
+ """
+ Traverses through the JSON object and converts non JSON-spec compliant
+ floats(nan, -inf, inf) to their string representations.
+
+ Parameters
+ ----------
+ json_object
+ JSON object
+ """
+ if isinstance(json_object, dict):
+ return {k: jsonify_floats(v) for k, v in json_object.items()}
+ elif isinstance(json_object, list):
+ return [jsonify_floats(item) for item in json_object]
+ elif isinstance(json_object, float):
+ if np.isnan(json_object):
+ return "NaN"
+ elif np.isposinf(json_object):
+ return "Infinity"
+ elif np.isneginf(json_object):
+ return "-Infinity"
+ return json_object
+ return json_object
+
+
 class Settings(BaseSettings):
  # see: https://pydantic-docs.helpmanual.io/#settings
  class Config:
@@ -191,7 +217,7 @@ def invocations() -> Response:
 
  log_throughput(req.instances, forecasts.timings)
 
- return jsonify(predictions=predictions)
+ return jsonify(predictions=jsonify_floats(predictions))
 
  return app
 

test/shell/test_shell.py

@@ -12,6 +12,7 @@
 # permissions and limitations under the License.
 
 # Standard library imports
+import json
 from typing import ContextManager
 
 # Third-party imports
@@ -23,7 +24,7 @@
 from gluonts.model.trivial.mean import MeanPredictor
 from gluonts.shell import testutil
 from gluonts.shell.sagemaker import ServeEnv, TrainEnv
-from gluonts.shell.serve import Settings
+from gluonts.shell.serve import Settings, jsonify_floats
 from gluonts.shell.train import run_train_and_test
 
 context_length = 5
@@ -161,3 +162,23 @@ def test_dynamic_shell(
  assert exp_samples_shape == act_samples.shape
  assert equals(exp_mean, act_mean)
  assert equals(exp_samples, act_samples)
+
+
+def test_as_json_dict_outputs_valid_json():
+ non_compliant_json = {
+ "a": float("nan"),
+ "k": float("infinity"),
+ "b": {
+ "c": float("nan"),
+ "d": "testing",
+ "e": float("-infinity"),
+ "f": float("infinity"),
+ "g": {"h": float("nan")},
+ },
+ }
+
+ with pytest.raises(ValueError):
+ json.dumps(non_compliant_json, allow_nan=False)
+
+ output_json = jsonify_floats(non_compliant_json)
+ json.dumps(output_json, allow_nan=False)