who send mqtt message to topic

i find the cloud app code is just update the device status, and the edge app just subcribe the mqtt topic.
i want to know,who send message to mq topic? kubeedge controller or cloudapp self.
thanks

Start by tracing the cloud app and edge app examples, then compare their MQTT topic handling with the KubeEdge controller entry points mentioned in the issue. Done means identifying which component publishes the device-status message and recording that flow clearly for readers.

Written by the indexing model from the issue text.