I have a postgreSQL CLoud SQL instance which I am connecting to via UNIX socket and the instance name from a Cloud Run container as per the documentation. With a public IP, this connection works fine. I was looking to turn off the public IP and only have a private IP, so I would not be charged for the public IP going forward.
When I first created the Cloud SQL instance, I only enabled the public IP. A couple of days later I enabled the private IP. For the assocaited network for the private IP, I accepted the default as the Cloud Run instance is in the same project.
When I turn off the public IP, my application can no longer connect to the Cloud SQL instance. I get a connection refused error:
sqlalchemy.exc.InterfaceError: (pg8000.core.InterfaceError) ('communication error', ConnectionRefusedError(111, 'Connection refused'))
As stated above, I did follow the instruaction on the Connecting to Cloud SQL from Cloud Run page:
https://cloud.google.com/sql/docs/postgres/connect-run
I even ran the gcloud command to update an the exsiting deployed revision after turning off the public IP and only having the private IP available but it made no difference.
Is a public IP required for a connection from Cloud Run to Cloud SQL? I do not see that in the connection documentation page. Or is there something else I missed when trying to switch over to only having a private IP? Or do I need to create a new Cloud Instance without a public IP and go through the instructions for connecting Cloud Run via an instance anme again?