MQTT statestream errors - Object of type ServiceEventData is not JSON serializable

[sjonez]

With MQTT statestream (https://www.home-assistant.io/integrations/mqtt_statestream/) configured in Home Assistant with all entities and attributes included, the following error gets logged many times with the myskoda integration installed, causing missed MQTT messages:

Logger: homeassistant
Source: helpers/json.py:67
First occurred: 25 February 2025 at 11:06:18 (289 occurrences)
Last logged: 08:22:08

Error doing job: Task exception was never retrieved (None)
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/components/mqtt_statestream/__init__.py", line 88, in _state_publisher
    encoded_val = json.dumps(val, cls=JSONEncoder)
  File "/usr/local/lib/python3.13/json/__init__.py", line 238, in dumps
    **kw).encode(obj)
          ~~~~~~^^^^^
  File "/usr/local/lib/python3.13/json/encoder.py", line 200, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/local/lib/python3.13/json/encoder.py", line 261, in iterencode
    return _iterencode(o, 0)
  File "/usr/src/homeassistant/homeassistant/helpers/json.py", line 67, in default
    return json.JSONEncoder.default(self, o)
           ~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/usr/local/lib/python3.13/json/encoder.py", line 180, in default
    raise TypeError(f'Object of type {o.__class__.__name__} '
                    f'is not JSON serializable')
TypeError: Object of type ServiceEventData is not JSON serializable

I've narrowed the issue down to the data and history attributes on the last_service_event entity, which I assume makes use of this ServiceEventData type. I've excluded that item from statestream for now, but is it possible to make it JSON serializable to prevent this from happening?

[WebSpider]

The MQTT integration is a prerequisite for MQTT Statestream to work.

We dont use the mqtt integration, we use MQTT as a method to receive our own push messages from MySkoda, but we do not use the HA MQTT integration.

Unless I offcourse misunderstand the problem

[sjonez]

Yes this has nothing to do with myskoda using MQTT.

Statestream is a core HA integration that mirrors changes to entities and attributes over MQTT. One of the entities that myskoda creates breaks this integration because the data it stores is not serializable. I first raised this issue with statestream but was then asked to raise it here as this problem has not been seen with any other entity across many integrations.

[dvx76]

Right, so this would be because the service_event entity returns the actual ServiceEventData objects in extra attributes (ServiceEvent.extra_state_attributes()). Likely the same issue with the last_operation entity.

Options:

• In ha-myskoda deserialize the event objects, either in extra_state_attributes() or in the coordinator where they get stored in coordinator.data.service_events
• See if the actual objects can be made json serializable on demand. Started reading https://stackoverflow.com/questions/3768895/how-to-make-a-class-json-serializable but ran out of time.

[WebSpider]

Yes this has nothing to do with myskoda using MQTT.

Statestream is a core HA integration that mirrors changes to entities and attributes over MQTT. One of the entities that myskoda creates breaks this integration because the data it stores is not serializable.

We will treats this as an enhancement request, not as a bug, since we aim to be compliant with HA, not all it's components, we're simply too young for that.

Thanks for the additional information👍