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I have a simple Django project with a PostgreSQL backend:

version: '3'
services:
  db:
    image: postgres:12
    ports:
      - '5432:5432'
    volumes:
      - postgres_data:/var/lib/postgresql/data/
    environment:
      POSTGRES_USER: pycharm
      POSTGRES_PASSWORD: pw123
      POSTGRES_DB: pycharm

  app:
    build: .
    command: python manage.py runserver 0.0.0.0:8000
    ports:
      - '8000:8000'
    volumes:
      - .:/app
    depends_on:
      - db

volumes:
  postgres_data:

With the following database settings in settings.py:

DATABASES = {
    "default": {
        "ENGINE": "django.db.backends.postgresql",
        "NAME": "pycharm",
        "USER": "pycharm",
        "PASSWORD": "pw123",
        "HOST": "db",
    }
}

And a simple test:

from django.test import TestCase

class MyTestCase(TestCase):

    def test_example(self):
        assert 1 == 1

Everything works fine when I run the project with docker-compose:

docker-compose up

I can exec into the container running the django app and successfully execute the test:

docker-compose run app bash
$ python manage.py test demo.tests.MyTestCase
Creating test database for alias 'default'...
System check identified no issues (0 silenced).
.
----------------------------------------------------------------------
Ran 1 test in 0.002s

OK
Destroying test database for alias 'default'...

I want to run the test in PyCharm, instead of having to exec into the container every time. I've setup the remote interpreter using Docker. However, when I run the test in PyCharm I get the following error:

django.db.utils.OperationalError: could not translate host name "db" to address: Name or service not known

It appears the app container can't find the database container when I run the test in PyCharm. This brings about two questions:

  1. Is there anyway to fix this so the app container can find the database container? I know docker networking on localhost is tricky.

  2. Is there anyway to setup the tests so they don't need to connect to the database container? I feel like Django or psycopg2 should be able to spin up a mock PostgreSQL service for the tests.

One way I've fixed this in the past is to use sqlite3 for my test database; however, I'm using fields that are not compatible with sqlite (such as ArrayField) so that's not an option.

Johnny Metz
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  • Add `hostname: db` to the db container spec? – richyen Dec 14 '19 at 22:02
  • @richyen getting the same error unfortunately – Johnny Metz Dec 14 '19 at 22:26
  • Does this answer your question? [Django docker - could not translate host name "db" to address: nodename nor servname provided, or not known](https://stackoverflow.com/questions/55081675/django-docker-could-not-translate-host-name-db-to-address-nodename-nor-serv) -- maybe you need to `link` in `docker-compose`? – richyen Dec 19 '19 at 18:39
  • u need to set the port on ur configuration on settings.py and try to use postgres 11 – khaled hadjali Jan 14 '20 at 09:40

2 Answers2

1

in ur yml file try to change 

services:
  db:
    image: postgres:11

in ur settings.py :

 DATABASES = {
        "default": {
            "ENGINE": "django.db.backends.postgresql_psycopg2",
            "NAME": "pycharm",
            "USER": "pycharm",
            "PASSWORD": "pw123",
            "HOST": "db",
            "PORT":5432,
        }
    }
khaled hadjali
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0

This catches me out every time I create a new pycharm/docker project.

Pycharm doesn't know about the db network, you'll need to change the pycharm run configuration to add db_default (or whatever the network's name is) as the network_mode on pycharm's run configuration.

run/debug config

where the network mode value comes from the network you get from docker inspect db

patl
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