I've done some research and based on it, my first question is:
It is not possible to establish an SSH tunnel from python script in Google Cloud Run to the server where the database is located natively, right?
If it is so, then, what workarounds would you suggest? I found a deprecated solution which is of course no longer intended to be used. The author wrote a new official guideline on how to approach this problem, but I do not understand in which way it solves it. In the end, we get a static IP address and we just need to whitelist it in our database?
So, please, suggest any other workarounds or comment on something that I missed or do not understand about the mentioned ones. Thank you!
Sharing this as a community wiki for the benefit of others
As discussed by @John Hanley