Solve docker django could not connect to server Connection refused postgre

Here is how I solve docker issue when running django could not connect to server Connection refused connecting to postgre database.

It may also work, for other than Django app.

Solution

Make sure your host value on .env file

DATABASE_HOST=db

or your settings.py file

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql',
        'HOST': f"{os.getenv('DATABASE_HOST', '')}",
        'PORT': f"{os.getenv('DATABASE_HOST_PORT', '5432')}",
        'NAME': f"{os.getenv('DATABASE_NAME', '')}",
        'USER': f"{os.getenv('DATABASE_USER', 'postgres')}",
        'PASSWORD': f"{os.getenv('DATABASE_PASSWORD', '')}"
    }
}

using the same name from docker-compose for the postgres image

for example if I have docker-compose.yml like this

version: '3.8'

services:
  web:
    build: .
    command: python manage.py runserver 0.0.0.0:8000
    volumes:
      - ./:/usr/src/app/
    ports:
      - 8000:8000
    # env_file:
    #   - ./.env.dev
    depends_on:
      - db
  db:
    image: postgres:14-alpine
    volumes:
      - postgres_data:/var/lib/postgresql/data/
    environment:
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=pass1234
      - POSTGRES_DB=test
    ports:
      - 5432:5432
      

volumes:
  postgres_data:

Then the DATABASE_HOST value should be db NOT localhost