Connecting to Postgres in docker-compose

[D4no0]

@fireproofsocks

Can someone clarify why this port is changing? And I seem to remember that the list of services defined inside of the docker-compose.yml corresponded to hostnames? Is that accurate? Like, instead of localhost, you might reference a hostname of db – but that doesn’t seem to work (even if I use the numeric extension).

Yes, you can reference containers by their service names, no numeric extension should be added, the name should be exactly as it is defined in docker-compose.yml.

@fireproofsocks

Looking more closely, it seems like the port directive in docker-compose.yml is being ignored. I’ve deleted the images and rebuilt this several times in the course of testing it, and each time the ports used come up with something more random (?) like 53665. If I set my database client to use that port, I can connect.

port option is for just exposing the container port to your host, the option port: "5432" will expose port 5432 from the container on your host on 5432.

I would recommend checking that your host 5432 port is free, otherwise map to a different port:

ports:
      - "5432:5433"

Also ensure that you are not connecting to some already exsting volumes with some strange Postgres configurations, a clean postgres/postgis container will always serve on port 5432 by default.

The last and the first thing I should have mentioned is to check that the database container has started as expected, it can happen that it will not start if it’s missing some mandatory configuration options (like username), you should have logs that it started accepting clients on port 5432.