2.7 KiB
| title | related_rules | |
|---|---|---|
| If it's a polling integration, set an appropriate polling interval |
|
import RelatedRules from './_includes/related_rules.jsx'
Reasoning
In an ideal world, all integrations would have a push-based data interface, where the device or service would let us know when new data is available. This would decrease the amount of requests Home Assistant would make.
However, in the real world, many devices and services are not capable of push-based communication, so we have to resort to polling. To do this responsibly, we should set an appropriate polling interval that will serve the majority of users.
There is no real definition of what an appropriate polling interval is, as it depends on the device or service being polled. For example, we should not poll an air quality sensor every 5 seconds, as the data will not change that often. In those cases, more than 99% of the users will be fine with a polling interval of a minute or more.
To give another example, if we poll a cloud service for solar panel data where the data is updated every hour. It would not make sense for us to poll every minute, as the data will not change between the polls.
For the users that do want to have more frequent updates, they can define a custom polling interval
Example implementation
There are two ways to set the polling interval.
Which one to use depends on how the integration polls for data.
When using an update coordinator, the polling interval can be set by setting the update_interval parameter or attribute in the coordinator.
When using the built-in entity update method, having set the should_poll entity attribute to True, the polling interval can be set by setting the SCAN_INTERVAL constant in the platform module.
coordinator.py:
class MyCoordinator(DataUpdateCoordinator[MyData]):
"""Class to manage fetching data."""
def __init__(self, hass: HomeAssistant) -> None:
"""Initialize coordinator."""
super().__init__(
hass,
logger=LOGGER,
name=DOMAIN,
update_interval=timedelta(minutes=1),
)
sensor.py:
SCAN_INTERVAL = timedelta(minutes=1)
class MySensor(SensorEntity):
"""Representation of a Sensor."""
_attr_should_poll = True
Additional resources
More information about polling can be found in the documentation.
Exceptions
There are no exceptions to this rule.