Volume doesn't work in a docker container and forgets data - django

Question

I'm trying to build Django + Docker + PostgreSQL
Dockerfile
FROM python:3.10.0-alpine
WORKDIR /usr/src/app
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1
RUN pip install --upgrade pip
RUN apk update
RUN apk add postgresql-dev gcc python3-dev musl-dev
COPY ./requirements.txt .
RUN pip install -r requirements.txt
COPY ./entrypoint.sh .
RUN sed -i 's/\r$//g' /usr/src/app/entrypoint.sh
RUN chmod +x /usr/src/app/entrypoint.sh
COPY . .
ENTRYPOINT ["/usr/src/app/entrypoint.sh"]
docker-compose.yml
version: '3.9'
services:
web:
build: .
command: gunicorn pets.wsgi:application --bind 0.0.0.0:8000
expose:
- 8000
env_file:
- .env
depends_on:
- db
db:
image: postgres:12.0-alpine
volumes:
- postgres_data:/var/lib/postgresql/data/
env_file:
- .env
nginx:
build: ./nginx
ports:
- 1337:80
depends_on:
- web
volumes:
postgres_data:
entrypoint.sh
#!/bin/sh
if [ "$DATABASE" = "postgres" ]
then
echo "Waiting for postgres..."
while ! nc -z $POSTGRES_HOST $POSTGRES_PORT; do
sleep 0.1
done
echo "PostgreSQL started"
fi
cd pets
python manage.py flush --no-input
python manage.py migrate
exec "$#"
So, when the container starts i use docker exec -it <container_id> python manage.py createsuperuser to create a superuser and then add some data to database.
But, when i use docker-compose stop and then running again with the same id the container forgets about the written data and everything has to be repeated.
Shouldn't volume solve this issue?