mqtt-bridge | Simple bridge to stream MQTT Broker data

The entry for the cert should not be the path to the certificate file, but the actual cert it's self. You need to read the file in and pass that.

Somethings like this:

Edit: Clarifying based on comment below...

There's two GCP components in play here. There's the MQTT topic (which is the /events topic), which is used by the device to talk to IoT Core. Then there's the projects/myprojectname/topics/sm1 which isn't in IoT Core, it's in Pub/Sub. When you send messages to the /events MQTT topic, IoT Core brokers the payloads from your device that was sent to the /events MQTT topic through to the Pub/Sub topic that was created and attached to the IoT Core registry where your device was registered.

To see those messages, you have to create a subscription in Pub/Sub on the topic projects/myprojectname/topics/sm1. If you go to the console, and Pub/Sub->topics. Click the three dots next to the topic and select "New subscription". Once you have the subscription, you can send some data from your device, then on commandline you can run (assuming you have the gcloud tools installed):

gcloud beta pubsub subscriptions pull --max-messages=3

To do anything with the messages, you can script subscribing to the Pub/Sub topic (check out the Pub/Sub APIs) to trigger on messages being added to the topic.

Original message:

Are you sending a config message to the device? The confusion might be that the MQTT topics are one-directional.

So: 1) the /events topic is for device->IoT Core. 2) the /config topic is for IoT Core Admin SDK->device

In another script somewhere, or from the IoT Core UI interface you need to send a configuration message to see the on_message fire properly.

In the IoT Core UI (on console.cloud.google.com) you can drill down to an individual device you have registered, and at the top of the screen, click on "Update Config". A popup window will come up that lets you send a text or a base64 encoded message to that device and it will come in on the /config topic.

You have the incorrect topic name.

It's confusing (I just hit this too).

The client ID (as you have) must be:

I'm a Googler (but I don't work in Cloud IoT).

Your code looks good to me and it should work. I will try it for myself this evening or tomorrow and report back to you.

I've spent the past day working on a Golang version of the samples published on Google's documentation. Like you, I was disappointed to not see all Google's regular languages covered by samples.

Are you running the code from a browser or is it running on Node.JS?

Do you have a package.json (if Node) that you would share too please?

Update

Here's a Node.JS (JavaScript but non-browser) that connects to Cloud IoT, subscribes to /devices/${DEVICE}/config and publishes to /devices/${DEVICE}/events.

https://gist.github.com/DazWilkin/65ad8890d5f58eae9612632d594af2de

• Place all the files in the same directory
• Replace values in index.js of the location of Google's CA and your key
• Replaces [[YOUR-X]] values in config.json
• Use "npm install" to pull the packages
• Use node index.js

You should be able to pull messages from the Pub/Sub subscription and you should be able to send config messages to the device.

here the IAM roles are being explained ...the paragraph here sounds alike what you describe:

On the IAM page in Google Cloud Platform Console, verify that the role Cloud IoT Core Service Agent appears in the Members list for the relevant project service account. (Look for the project service account that ends in @gcp-sa-cloudiot.iam.gserviceaccount.com.)

If the Cloud IoT Core Service Agent role does not appear in the Members list, use gcloud to add the cloudiot.serviceAgent role to the relevant project service account. This role includes permission to publish to Pub/Sub topics.

if not yet having installed it, the Cloud SDK is required for all those gcloud CLI commands, which can be used to list & edit the configurations (of which all can be done through the console, as well)... it's maybe easier, because all of the examples there use it, too.

update ...

concerning JWT refresh tokens, see this article or have some Q & A or the specification: JSON Web Token (JWT), JSON Web Token (JWT) Profile for OAuth 2.0 Client Authentication and Authorization Grants. here's another relevant article: https://medium.com/google-cloud/refreshing-json-web-tokens-jwts-for-google-cloud-iot-core-897318df3836

You can create bridges with mosquitto, the "Configuring Bridges" section of the man page covers all the options, but the basics you will need are: