How to script adding a new User/Database to an existing database instance?

[nodje]

I must be the nth person asking for this, but I can find a solution for this anywhere.

Since, as per the doc, Warning: scripts in /docker-entrypoint-initdb.d are only run if you start the container with a data directory that is empty; any pre-existing database will be left untouched on container startup,it seems there is no way to add a script to /docker-entrypoint-initdb.d to create a new User/Database couple when you add, say a new container to a docker-compose file and want to share a single postgres instance.

Or am I understanding this wrong?

In anycase, in my tests I get a PostgreSQL Database directory appears to contain a database; Skipping initialization in the logs, confirming the behaviour.

[wglambert]

You'd have to do it manually or devise some automated connection to the database to execute the script, the entrypoint won't modify existing data

[tianon]

See #929, #173, #821, #191 (to link a few similar issues) -- hopefully one of these has some helpful clues for helping you implement what you're looking for 👍