Tracker Serialization of Decimal Value

[rgstephens]

Rasa version: 1.5.1

Issue:
There are Decimal values associated with slots in our DynamoDB tracker store. When an action is run and the tracker store is json encoded it fails when attempting to serialize the Decimal value. This is similar to issue #2265

Error (including full traceback):

2020-01-23 11:47:22 DEBUG    rasa.core.processor  - Object of type Decimal is not JSON serializable
Traceback (most recent call last):
File "/Users/dsammut/Repos/chatbot-rasa/venv/lib/python3.7/site-packages/rasa/core/processor.py", line 564, in _run_action
events = await action.run(output_channel, nlg, tracker, self.domain)
File "/Users/dsammut/Repos/chatbot-rasa/venv/lib/python3.7/site-packages/rasa/core/actions/action.py", line 541, in run
json=json_body, method="post", timeout=DEFAULT_REQUEST_TIMEOUT
File "/Users/dsammut/Repos/chatbot-rasa/venv/lib/python3.7/site-packages/rasa/utils/endpoints.py", line 146, in request
**kwargs,
File "/Users/dsammut/Repos/chatbot-rasa/venv/lib/python3.7/site-packages/aiohttp/client.py", line 1012, in __aenter__
self._resp = await self._coro
File "/Users/dsammut/Repos/chatbot-rasa/venv/lib/python3.7/site-packages/aiohttp/client.py", line 365, in _request
data = payload.JsonPayload(json, dumps=self._json_serialize)
File "/Users/dsammut/Repos/chatbot-rasa/venv/lib/python3.7/site-packages/aiohttp/payload.py", line 389, in __init__
dumps(value).encode(encoding),
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/__init__.py", line 231, in dumps
return _default_encoder.encode(obj)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/encoder.py", line 199, in encode
chunks = self.iterencode(o, _one_shot=True)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/encoder.py", line 257, in iterencode
return _iterencode(o, 0)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/encoder.py", line 179, in default
raise TypeError(f'Object of type {o.__class__.__name__} '
TypeError: Object of type Decimal is not JSON serializable

Content of configuration file (config.yml) (if relevant):

language: en
# pretrained_embeddings_convert
pipeline:
- name: "WhitespaceTokenizer"
- name: "ConveRTFeaturizer"
- name: "EmbeddingIntentClassifier"
policies:
- name: FormPolicy
- name: MemoizationPolicy
- name: KerasPolicy
- name: MappingPolicy
- name: TwoStageFallbackPolicy
  nlu_threshold: 0.65
  core_threshold: 0.3
  fallback_core_action_name: action_fallback_transfer
  fallback_nlu_action_name: action_fallback_transfer

[kawtarZ]

We encountered the same bug as yours. have you found any solution for it ?

[domsammut]

Our organisation encountered this issue and wrote some workarounds. However the workaround developed impacts all trackers used, so we didn't create a PR as it would require testing all trackers, which we don't have the capacity to do (we only validated it worked when using the DynamoDB tracker store).

[kawtarZ]

We also developped a temporary workaround by adding a static method in the class RemoteAction in rasa/core/actions/actions.py that convert all the Decimal values returned by the tracker into strings.