Google IOT - device subscribe to something else than /devices/XXXX/config

manpreet Best Answer 3 years ago

_x000D_ I am not an expert on Google IoT, but few days ago I got the same doubts about it. Apparently, although we can publish to /events, /config and /state topics, using MQTT protocol, only topic /config and, maybe, /state can work through subscriptions with the same protocol. The conclusion I got, after reading many times the documentation, that is not so clear, and asking some questions here at stackoverflow is: you can not use MQTT to subscribe to any topic in order to receive those data sent to /events topic. To accomplish this, you have to create a Pub/Sub topic associating it to your device: On Google Cloud IoT Core Console, click on your registry ID; Create a standard telemetry topic; After topic created, click on the topic to see its details; Its details will open on Google Cloud Pub/Sub panel; In this panel, you can create a subscription to the created topic, by clicking on the "create subscription button". Now that you have a "google cloud pub/sub topic" linked to "google cloud iot core /events telemetry MQTT topic" and a respective subscription, you can use the google pub/sub library to receive notifications through created subscription when data are sent to /events topic. Maybe the following link can also help: https://cloud.google.com/iot/docs/how-tos/devices#creating_a_device_registry_with_multiple_pubsub_topics I hope this can help you. If I made any mistake in my answer, may someone edit it with some improvement or correction.