allow docker-entrypoint postgres startup to listen on tcp as well as unix sockets

[dmepham]

No description provided.

[yosifkit]

Not listening for outside connections during initialization is on purpose (#75, and #440). There would be no way for the temporary postgres server to know when outside connections are done. These outside connections should just wait for the startup to complete (ie, the postgres port is ready to accept connections) or be run through scripts in /docker-entrypoint-initdb.d/.

[dmepham]

@yosifkit sorry, I actually raised this PR by accident. Thanks for the helpful background info.

My original intention was to apply database initialization by putting a shell script in /docker-entrypoint-initdb.d/, which would in turn run a liquibase command to apply database updates. But because liquibase uses the JDBC to connect to the database, and JDBC requires connection via tcp, the /docker-entrypoint-initdb.d/ and liquibase (or any initialization process using JDBC) can't be used together.

After reading your comments here and a comment here, it looks like the best solutions may either:

1. Applying liquibase updates after the docker container is starter and the database is listening on tcp, or,
2. Restarting the temporary database in a script within /docker-entrypoint-initdb.d/, and then applying liquibase updates. As you noted, this may present issues with health checks.

This comment and PR are probably more suited to a comment on an existing issue or PR, but I wanted to drop it here anyway for the record. Thanks for the help.