Django connection to postgres by docker-compose

Question

My django project cannot connect to postgres database container. What I should to do?

It crashes on commands python manage.py collectstatic --noinput &&

Answer 1

Each container in docker by default gets its own hostname and IP. When compose spins up the containers for you, it also places all of the containers on a network by default to permit DNS based discovery.

What this means is that your database is not reachable on localhost, but you can reach it by the service name "db". Change this line in your settings.py:

    'HOST': 'localhost',

to:

    'HOST': 'db',

Answer 2

Here's what worked for me:

in compose:

version: '3.7'
services: 
  web:
    build: .
    command: python /code/manage.py runserver 0.0.0.0:8000
    volumes: 
        - .:/code
    ports: 
        - 8000:8000
    environment: 
        - DB_HOST=db
        - DB_NAME=web
        - DB_USER=postgres
        - DB_PASSWORD=postgres

    depends_on: 
        - db

  db:
    image: postgres:12-alpine
    volumes: 
        - postgres_data:/var/lib/postgresql/data/
    environment: 
        - POSTGRES_DB=web
        - POSTGRES_USER=postgres
        - POSTGRES_PASSWORD=postgres
volumes:
   postgres_data:

in settings:

DATABASES = {
'default': {
    'ENGINE': 'django.db.backends.postgresql',
    'NAME': os.environ.get('DB_NAME'),
    'USER':os.environ.get('DB_USER'),
    'PASSWORD': os.environ.get('DB_PASSWORD'),
    'HOST':os.environ.get('DB_HOST'),
    'PORT':5432,
 }
}