I'm building automation for a Nest thermostat. The automation infrastructure is attempting to use GCP's Pub/Sub and Cloud Functions services.
When creating a new project on Google's Device Access Console I don't see a way to update the Pub/Sub topic. Technically, there is an edit button, but the topic text field is greyed out and the string can't be changed. Nor do I see a way to access the auto-populated topic from inside my GCP project. As a result, I don't see how I can build a Function subscriber to the topic from my GCP project.
Interestingly, there is a way to create a Pub/Sub subscriber because that interface provides a method to manually enter the Pub/Sub topic that is shown on the Device Access Console. I've done this and verified that device data flows correctly.
There is no manual entry option when creating a Function that subscribes to a topic.
When I click on the topic listed on the Pub/Sub Subscriber, I'm presented with an error message,
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How can I build a Cloud Function that responds to Pub/Sub events for the device?