I have developed a device that is able to connect to Google IoT Core through the MQTT protocol, I can publish MQTT messages on telemetry topics (/devices/DEVICE_ID/events).
But I can't figure out how to subscribe my device to a generic topic and send messages from cloud to device via this topic.
Through the console I created the topic MyTestTopic and a subscription MyTestTopic-sub, I guess that somehow I have to subscribe my device to the subscription MyTestTopic-sub, but I don't know to which topic I have to subscribe my device.
I tried to subscribe my device to the following topics:
projects/PROJECT_ID/topics/MyTestTopic
projects/PROJECT_ID/topics/MyTestTopic-sub
/devices/DEVICE_ID/events/MyTestTopic
/devices/DEVICE_ID/events/MyTestTopic-sub
the subscription to these topics seems to be successful, but the device does not receive the messages I send from the console.
Any suggestions please?
I found this thread (Google Cloud IoT - Invalid MQTT publish topic) from 4 years ago, from which I understand that it is possible to subscribe only to some predefined topics, also from the various documents I have read I understand that Google IoT Core allows devices to subscribe to only two topics: /devices/{device-id}/config and /devices/{device-id}/commands/#
Has anything changed since then?
So to be clear, there are two different "topics" in play here. There's the MQTT topics that are described in the docs you found, config and commands. Those are subscribed to on the device using an MQTT client (e.g. Paho MQTT), and sent down to the device from somewhere else via the IoT Core Admin APIs. Then there's Pub/Sub topics. Out of the box, a device using IoT Core does not directly interact with Pub/Sub at all. They publish/receive via the MQTT topics only. So if you register a device with IoT Core, all messages come and go via the MQTT bridge (or HTTPS).
What Gambit support linked to in that github repo is a direct subscription to a Pub/Sub topic (not MQTT). If you look at the Python code, it's establishing proper Google Cloud Credentials via a json token (service account bearer token) that needs to be present on the device or a proxy device. Depending on the device you're using, that may not be possible of course (implementing GCP APIs on a microcontroller is difficult at best).
The easiest way I've seen this done is to implement a Cloud Function that subscribes to a Pub/Sub topic you want to use, and it implements the proper IoT Core Admin calls to push the Pub/Sub messages down to the device as needed. But of course, it all depends on what you're trying to do.
Related
I am publishing ESP data to Google Cloud IOT via MQTT to a particular topic. But If I have many devices data, then is it necessary to create different topic for each device? If Yes, then how can I trigger a single cloud function for multiple topics.
I couldn't find it anywhere on the Google Cloud Platform Documentation. So please help me!.
No, the message contain the attributes of your device. Like this, you can know the context of the message and process all the messages by the same Cloud Functions.
In my project multiple IoT devices need to publish to a single topic and cloud functions listening to that topic need to process data published by IoT devices. Multiple devices should be able to publish at the same time.A MQTT broker logic is needed. But in Google IoT Core "The MQTT bridge allows only a single connection for a given device ID. If a second device connects with the ID of a device that is already connected, the older device connection will be closed automatically.".
I am new to google cloud IoT and trying to understand basic concepts. I have looked into gateways but I am not sure that gateways work as broker. Can multiple devices publish through a gateway to a same single topic? or should I implement/add a MQTT broker(mosquitto I guess) myself or is there an another way to use google Cloud IoT in my case? Could you guys direct me to the right direction. Opening sub/pub topics for each device doesn't sound right because in my project there can be thousands of IoT devices.
Let all the devices in the registry publish messages to the common topic given to the registry.Then trigger a cloud function with this topic.
You can process the messages with cloud function based on the deviceId
I am new to Google Clout Iot core. I just tried the iot core, registered the device and published some data on a topic.
Now i am wondering is only Google functions are used to get/subscribe data from it? or can i also used the data published from a device directly into my applications e.g. node.js or python? like it is usually subscribed through a normal MQTT topic? I dont need a serverless architecture i want to use the data from google iot into my server and store/use it from there..
thanks a lot!
When a message arrives over MQTT or HTTP from a device over IoT Core, that message is published on a GCP Pub/Sub topic using the GCP Pub/Sub infrastructure. What this means is that you can develop a consuming application however you like as long as that application consumes the message from Pub/Sub.
The diagram shown here from the documentation is a good reference.
GCP exposes the API for Pub/Sub to be a subscriber. There are language bindings for a variety of languages.
Cloud Functions is typically seen as a serverless consumer of Pub/Sub messages as it scales to zero and can scale up if there is bursty load. However, there is nothing to prevent you from writing Compute Engine hosted applications or Container hosted applications which can act as subscribers.
References:
Cloud Pub/Sub documentation
Cloud Pub/Sub Client Libraries
I think your question is more on the architectural side of things. You can use IoT Core with something like Pub/Sub and write the data to Cloud Storage in order to later consume it with an application.
I would recommend you to check some of the diagrams from this page if you are interested in knowing which products you could use to best fit your needs.
I hope you find this useful!
I have an android device that is registered to an SNS Platform Application. So it is a platform endpoint (in terms of aws sns). It has subscribed a total of 20 Sns Topics.
If I have another device (Android or Iphone), which is also an SNS platform endpoint, I would like it to be subscribed to same SNS topics.
Basically, I want to subscribe sns topics from one device. And if I install this application to another device, I want all of my subscription to be replicated on that other device as well. I hope I made my self clear.
I am using AWS SDK for Asp.net core.
Thanks for helping out.
Essentially for GCM another device would require another subscription.
The logic below will not work automatically unless you program it in your application.
Basically, I want to subscribe sns topics from one device. And if I install this application to another device, I want all of my subscription to be replicated on that other device as well. I hope I made my self clear.
Please check this example in mobile-platform-endpoint documentation, it is not the same scenario but can be used as reference.
Say I have 1000 IoT devices. Each device sends telemetry data to the Azure cloud each second. There is mobile app which displays that telemetry data. Mobile user can see data from specific IoT device only, based on his login. It's not an issue to receive all those d2c messages in the cloud, for example with Event Hubs (initially i wanted to use IoT Hub, but it's pretty expensive with huge amount of messages). It's also clear how to get general event stream (for example, by listening to events endpoint in IoT hub). However, this stream gives all messages, from all devices. Receiving all messages in mobile app and filtering them there does not look like right choice. How can I subscribe to events from specific IoT device only? Can I do this with Event Hubs and/or IoT Hub only, or do I need to utilize other Azure services? If yes, what will be the most cheap solution.
Update:
Original question was just about Azure. But is it possible to achieve what I need with AWS without requiring adding multiple parts to the system. Is Message Broker for AWS IoT what I need here (as I understood, this is built in functionality of AWS IoT Core)?