Could IoT Edge Module know its own downstream device ID list? How can we fetch that?

Question

Hi,

As mentioned in the title, can we fetch the downstream devices from the IoT Edge gateway?

Thanks in advance.

Answer 1

Hello @KunLi-4284,

you want to know if Azure IoT Edge has knowledge of downstream devices.

Azure IoT Edge modules are behaving 'sandboxed'. They just do their job and do not know about other modules or devices.

You can get them notified about other devices/modules in two ways:

1 You can submit data (with child device names) to the module using eg. Desired property or a direct method (which needs a live connection to the device and is not persisted by default)
2 Route child device messages to the input of a custom module

Cloud messages from child devices flow through an Azure IoT Edge device configured as transparent proxy.

See also this blog where an edge module reads a message from a child device and sends back commands for a local feedback loop.

This way, a module can build up a list of child devices.