A device shadow is a JSON document that is used to store and retrieve device state information. The device shadow is associated with AWS IoT thing object. Any application or service which wants to know the device state; can access the device shadow irrespective whether the device is connected to AWS IoT or not. Shadow communications use request/response model using the publish/subscribe communication model of MQTT. Every shadow action consists of a request topic, a successful response topic (accepted), and an error response topic (rejected).
In this workshop, you perform update, get and delete actions on the device shadow document using MQTT based communication. You will use MQTT client as part of AWS IoT Service to complete the workshop.
