Error: Postgres database import in docker container

Set up a database dump mount

You'll need to mount the dump into the container so you can access it. Something like this in docker-compose.yml:

db:  volumes:    - './db_dump:/db_dump'

Make a local directory named db_dump and place your db_dump.gz file there.

Start the database container

Use POSTGRES_DB in the environment (as you mentioned in your question) to automatically create the database. Start db by itself, without the rails server.

docker-compose up -d db

Import data

Wait a few seconds for the database to be available. Then, import your data.

docker-compose exec db gunzip /db_dump/db_dump.gzdocker-compose exec db psql -U postgres -d dbname -f /db_dump/db_dump.gzdocker-compose exec db rm -f /db_dump/db_dump.gz

You can also just make a script to do this import, stick that in your image, and then use a single docker-compose command to call that. Or you can have your entrypoint script check whether a dump file is present, and if so, unzip it and import it... whatever you need to do.

Start the rails server

docker-compose up -d web

Automating this

If you are doing this by hand for prep of a new setup, then you're done. If you need to automate this into a toolchain, you can do some of this stuff in a script. Just start the containers separately, doing the db import in between, and use sleep to cover any startup delays.

web_1 exited with code 0

Did you tried check the log of web_1 container? docker-compose logs web

I strongly recommend you don't initialize your db container manually, make it automatically within the process of start container.

Look into the entrypoint of postgres, we could just put the db_dump.gz into /docker-entrypoint-initdb.d/ directory of the container, and it will be automatic execute, so docker-compose.yml could be:

db:  volumes:    - './initdb.d:/docker-entrypoint-initdb.d'

And put your db_dump.gz into ./initdb.d on your local machine.

When you use commanddocker-compose run -d db

you run a separate container it means you are running 3 containers where 1 is application 2 are dbs. The container you run using above command will not be a part of service. compose is using separate db.

So instead of running docker-compose up -d db run docker-compose up -d and continue with your script