How to update entity without RuntimeError("Cannot be called from within the event loop")

Development
1

Here is the background:
I am extending a custom component from HACS. It includes 2 sensors which pull in data from 2 cloud sources; both have details about the expected precipitation but are ‘unparsed’ and used for a frontend card.

The extension i’ve made combines both sources. From my combined data, i want to expose 4 new sensors.

In my ‘combination’ logic sensor, i’ve subscribed to state changes;

async_track_state_change(hass, [ "sensor.neerslag_buienalarm_regen_data", "sensor.neerslag_buienradar_regen_data" ], self.parse_rain_source_data)

This means that whenever either of the sources update, my method self.parse_rain_source_data executes.

In the meantime, i have also registered my new sensors, one is called “sensor.is_it_raining” which I want to update from my callback method;

    @callback
    def parse_rain_source_data(self, entity_id, old_state, new_state):

However, whenever i try to call from within that callback

self.hass.states.set("sensor.is_it_raining", "yes")

Hass bails with an error:

  File "/config/custom_components/neerslag/sensor.py", line 421, in update_sensor_state_and_attributes
    self.hass.states.set(entity_id, new_state, inputAttributesObject, True)
  File "/usr/src/homeassistant/homeassistant/core.py", line 1286, in set
    run_callback_threadsafe(
  File "/usr/src/homeassistant/homeassistant/util/async_.py", line 51, in run_callback_threadsafe
    raise RuntimeError("Cannot be called from within the event loop")
RuntimeError: Cannot be called from within the event loop

And i have no clue how to solve this :slight_smile: Any pointers so that i can update the sensor states in this callback?

2

Anybody from the devs maybe?

3

IMO you’re approaching this from an odd angle. If you’re extending an existing integration, you should just extend it properly by adding the 4 additional sensors using the metadata instead of the other states.

Otherwise, if you’re planning on creating a completely new integration that uses existing sensors, then you should look at one of the utility integrations. Many of them contain the information you’re looking for.

For example:

    async def async_added_to_hass(self):
        """Handle added to Hass."""
        self.async_on_remove(
            async_track_state_change_event(
                self.hass,
                [ "sensor.neerslag_buienalarm_regen_data", "sensor.neerslag_buienradar_regen_data" ],
                self.parse_rain_source_data,
            )
        )

…

    @callback
    def parse_rain_source_data(self, event):
        """Handle sensor state changes."""
        if (new_state := event.data.get("new_state")) is None:
            return

        #do everything else here

        # end with with a "yo write the state"
        self.async_write_ha_state()