Docker for Rails Developers

Connecting to Postgres from a Separate Container

As you become more and more comfortable with using Compose, you’ll find that you trust it to do what you need. A quick docker-compose ps is probably all you need to verify a service is running (sometimes you may even skip that).

However, since running services like Postgres inside a container is still fairly new for us, let’s take the extra step of manually connecting to it from a different container, just like we did with Redis. While learning, for me at least, this helps build my confidence in the tools.

As was the case with Redis, the postgres image comes preinstalled with psql—the Postgres client. This means we can piggyback on our new database service in order to run a one-off container, ...