Feature Overview
IoT Hub Device State service is responsible for monitoring the device connectivity state and triggering the device connectivity events that are pushed to the Rule Engine. As a platform user, you are able to define how to react to these events.
Supported events are:
- Connect event - triggered when a device connects to IoT Hub. Relevant in the case of session-based transports like MQTT. It is also triggered for HTTP transport, but in this case, it will be triggered on each HTTP request;
- Disconnect event - triggered when the device disconnects from IoT Hub. Relevant in the case of session-based transports like MQTT. It is also triggered for HTTP transport, but in this case, it will be triggered on each HTTP request;
- Activity event - triggered when a device pushes telemetry, attribute update, or RPC command;
- Inactivity event - triggered when a device was inactive for a certain period of time. Please note that this event may be triggered even without disconnect event from the device. Typically, means that there were no activity events triggered for a while.
Device State service is responsible for maintaining the following server-side attributes:
- active - represents current device state, either true or false;
- lastConnectTime - represents the last time device was connected to IoT Hub, number of milliseconds since January 1, 1970, 00:00:00 GMT;
- lastDisconnectTime - represents the last time device was disconnected from IoT Hub, number of milliseconds since January 1, 1970, 00:00:00 GMT;
- lastActivityTime - represents the last time device pushed telemetry, attribute update, or RPC command, number of milliseconds since January 1, 1970, 00:00:00 GMT;
- inactivityAlarmTime - represents the last time inactivity event was triggered, number of milliseconds since January 1, 1970, 00:00:00 GMT.
Configuration
Device State service uses a global configuration parameter for inactivity timeout. This parameter is defined in thingsboard.yml (state.defaultInactivityTimeoutInSec) and by default it is set to 10 seconds. A user can overwrite this parameter for an individual device by setting the “inactivityTimeout” server-side attribute (value is set in milliseconds).
Device State service uses a global configuration parameter to detect inactivity events. This parameter is defined in thingsboard.yml (state.defaultStateCheckIntervalInSec) and by default it is set to 10 seconds.
Next steps
- Getting started guides - These guides provide quick overview of main IoT Hub features. Designed to be completed in 15-30 minutes.
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Connect your device - Learn how to connect devices based on your connectivity technology or solution.
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Data visualization - These guides contain instructions how to configure complex IoT Hub dashboards.
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Data processing & actions - Learn how to use IoT Hub Rule Engine.
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IoT Data analytics - Learn how to use rule engine to perform basic analytics tasks.
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Hardware samples - Learn how to connect various hardware platforms to IoT Hub.