User not created in postgres docker image - postgresql

Question

I have a docker image that's not accepting credentials for a user that is defined in the yaml docker-compose file. When I go to the docker console for the container and check users it only lists postgres. Not sure what I am missing - here's the yaml file:
version: '3.8'
services:
db:
container_name: drewreport_container
image: postgres
restart: always
environment:
POSTGRES_PASSWORD: mpassword
POSTGRES_USER: thedrewreport
POSTGRES_DB: thedrewreportdb
ports:
- "5432:5432"
volumes:
- thedrewreportdata:/var/lib/postgresql/data/
volumes:
thedrewreportdata:
Any ideas?

Answer 1

I can't reproduce your problem. Running docker-compose up, I see:
Creating network "docker_default" with the default driver
Creating volume "docker_thedrewreportdata" with default driver
Creating docker_client_1 ...
Creating docker_db_1 ...
Creating docker_client_1 ... done
Creating docker_db_1 ... done
Attaching to docker_db_1, docker_client_1
[...]
db_1 | 2021-07-19 23:03:39.676 UTC [1] LOG: database system is ready to accept connections
If I then connect with psql, I can authenticate using the username
and password you've defined in your docker-compose.yml:
# psql -h localhost -U thedrewreport thedrewreportdb
Password for user thedrewreport:
psql (13.3 (Debian 13.3-1.pgdg100+1))
Type "help" for help.
thedrewreportdb=# \du
List of roles
Role name | Attributes | Member of
---------------+------------------------------------------------------------+-----------
thedrewreport | Superuser, Create role, Create DB, Replication, Bypass RLS | {}
thedrewreportdb=#
Note that any volumes specified in your docker-compose.yml will
persist between a docker-compose down and a docker-compose up, so
if you ever brought your stack up with different credentials, those
will never be replaced unless your explicitly destroy the volume by
running docker-compose down -v.
You can tell that docker-compose is re-using a volume if you don't
see a message like this when you run docker-compose up:
Creating volume "docker_thedrewreportdata" with default driver

Answer 2

If existing, the existing DB data you mount to /var/lib/postgresql/data/ will take precedence over the environment variables to initialize it.
You have 2 options:
Update the existing DB data to add your user / password / database. To do so you can use docker compose exec db bash and then connect using psql command to make your changes.
Delete or move your existing thedrewreportdata local volume, for instance updating it to ./thedrewreportdata_postgres:/var/lib/postgresql/data/
Once done, you can use docker compose exec db psql --username thedrewreport --dbname thedrewreportdb to doublecheck you can connect with your credentials to the updated DB.