Django application inside Docker can't find Postgres container

General
,
1

I am trying to connect Database container form offical Postgres image with Django container. But it can’t find Postgres container. I checked Firewall is enabling specifyed ports, containers are under same network. Project works on localhost with Docker Desktop. But can’t connect to Postgres container on Ubuntu Server

my docker-compose looks like this:

version: '3.8'

services:
  qutqaruv:
    build: ./app
    command: gunicorn qutqaruv_core.wsgi --bind  0.0.0.0:8001
    volumes:
      - ./app/:/usr/src/app/
      - static_volume:/static
    ports:
      - "8001:8001"
    env_file:
      - ./app/.env.dev
    depends_on:
      qutqaruv-db:
        condition: service_healthy
    restart: always
  nginx:
    image: nginx:1.22.1
    ports:
      - "82:8081"
    volumes:
      - ./nginx/nginx-setup.conf:/etc/nginx/conf.d/default.conf:ro
      - static_volume:/static
    depends_on:
      - qutqaruv
  qutqaruv-db:
    image: postgres:15
    healthcheck:
      test: [ "CMD-SHELL", "pg_isready -U qutqaruv -d qutqaruv_dev" ]
      interval: 5s
      timeout: 5s
      retries: 5
    volumes:
      - postgres_data:/var/lib/postgresql/data/
    environment:
      - POSTGRES_USER=qutqaruv
      - POSTGRES_PASSWORD=qutqaruv
      - POSTGRES_DB=qutqaruv_dev

volumes:
  postgres_data:
  static_volume:

Dockerfile:

# pull official base image
FROM python:3.11.2-slim-buster

# set working directory
WORKDIR /usr/src/app

# set environment variables
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1

# updated
# install system dependencies
RUN apt-get update \
  && apt-get -y install gcc postgresql \
  && apt-get clean

# install dependencies
RUN pip install --upgrade pip
COPY ./requirements.txt .
RUN pip install -r requirements.txt

# new
# copy entrypoint.sh
RUN apt-get update && apt-get install -y netcat
COPY ./entrypoint.sh /usr/src/app/entrypoint.sh
RUN chmod +x /usr/src/app/entrypoint.sh

# add app
COPY . .

# new
# run entrypoint.sh
ENTRYPOINT ["/usr/src/app/entrypoint.sh"]

entrypoint.sh:

#!/bin/sh

echo "Waiting for postgres..."

while ! nc -z $SQL_HOST $SQL_PORT; do
  echo $SQL_HOST $SQL_PORT
  sleep 0.1
  echo "Got lost in this process"
done
echo "PostgreSQL started"

python manage.py flush --no-input
python manage.py migrate
python manage.py collectstatic --no-input


exec "$@"