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Set Parallel updates

Reasoning​

Some devices or services don't like receiving a lot of requests at the same time. To avoid that, Home Assistant has a built-in feature to limit the number of requests that are sent to a device or service at the same time.

This will be applied to both entity updates and actions calls.

We consider it a good practice to explicitly set the number of parallel updates.

Example implementation​

In the example below, we set the number of parallel updates to 1. Which means if there are more entities on the sensor platform, they will be updated one by one. If there is no need to limit the number of parallel updates, you can set it to 0.

sensor.py

PARALLEL_UPDATES = 1

class MySensor(SensorEntity):
    """Representation of a sensor."""

    def __init__(self, device: Device) -> None:
        """Initialize the sensor."""
        ...
info

When using a coordinator, you are already centralizing the data updates. This means you can set PARALLEL_UPDATES = 0 for read-only platforms (binary_sensor, sensor, device_tracker, event) and only the action calls will be relevant to consider for setting an appropriate number of parallel updates.

sensor.py

# Coordinator is used to centralize the data updates
PARALLEL_UPDATES = 0

class MySensor(CoordinatorEntity, SensorEntity):
    """Representation of a sensor."""

    def __init__(self, device: Device) -> None:
        """Initialize the sensor."""
        ...

Additional resources​

For more information about request parallelism, check the documentation for it.

Exceptions​

There are no exceptions to this rule.