my PostgreSQL docker image database doesn't exist on Django

Question

I am doing a django API with docker and postgresql, i set up a docker compose file to use a db network which is a postgresql image and an app network which is my django app. I don't know what is happening (i followed a tutorial) but my configuration isn't working, it give me an error on django that the database doesn't exist.

Here is the files:

docker-compose.yml

version: "3"

services:
  app:
    build:
      context: .
    ports:
      - "8000:8000"
    volumes: # Any change made on the project will be reflected on the container
      - ./app:/app
    command: >
      sh -c "python manage.py wait_for_db &&
             python manage.py migrate &&
             python manage.py runserver 0.0.0.0:8000"
    environment:
      - DB_HOST=db
      - DB_NAME=recipe
      - DB_USER=postgres
      - DB_PASS=supersecretpassword
    depends_on:
      - db
  db:
    image: postgres:10-alpine
    environment:
      - POSTGRES_DB=recipe
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=supersecretpassword

Dockerfile

FROM python:3.7-alpine
LABEL maintainer="trolliama"

# Recommended - Don't Allow the python buffer the outputs
ENV PYTHONUNBUFFERED 1 

COPY ./requirements.txt /requirements.txt
# Dependencies to run postgresql
# apk it's the packege install of alpine like: apt
# apk add == apt install
RUN apk add --update --no-cache postgresql-client
RUN apk add --update --no-cache --virtual .tmp-build-deps \
    gcc libc-dev linux-headers postgresql-dev
RUN pip install -r /requirements.txt

RUN apk del .tmp-build-deps

RUN mkdir /app
# Changes for the app dir
WORKDIR /app 
COPY ./app /app

# By default the docker uses the root user to run the container so..
# Create a user with for just run the application
RUN adduser -D user
# Changes to the user
USER user

settings.py

DATABASES = {
    "default": {
        "ENGINE": "django.db.backends.postgresql",
        "HOST": os.environ.get("DB_HOST"),
        "NAME": os.environ.get("DB_NAME"),
        "USER": os.environ.get("DB_USER"),
        "PASSWORD": os.environ.get("DB_PASS"),
    }
}

requirements.txt

django>=2.1.3,<2.2.0
djangorestframework>=3.9.0, <3.10.0
psycopg2>=2.7.5,<2.8.0
flake8>=3.6.0,<3.7.0

So this is the config, in the tutorial i also set up this django custom command that just check if the database is up and exist (wait_for_db).

wait_for_db.py

import time

from django.db import connections
from django.db.utils import OperationalError
from django.core.management.base import BaseCommand


class Command(BaseCommand):
    """Command to wait for DB"""

    def handle(self, *args, **options):
        self.stdout.write("Waiting for database...")
        db_conn = None
        while not db_conn:
            try:
                db_conn = connections["default"].cursor()
                self.stdout.write("db_conn: {}".format(db_conn.cursor()))
            except OperationalError:
                self.stdout.write("Database not available")
                time.sleep(1)

        self.stdout.write(self.style.SUCCESS("Database available"))

So when i remove this .cursor() off the connections["default"] i get this error when execute docker-compose up saying that i don't have a recipe db.

django.db.utils.OperationalError: FATAL:  database "recipe" does not exist

If i don't remove the cursor() it gets in a loop

So I checked that the docker compose db network was creating the db using docker-compose run db and going to the created container to get the databases and ther was the recipe db. Any ideas of what is happening?

Answer 1

I managed to fix this with those commands:

$ docker-compose down
$ docker-compose up --force-recreate

Here is the link for the issue