how to separate INSTALLED_APPS or dev and prod

[sant527]

In django development i am planning to install django-extensions app

I have to add it to the INSTALLED_APPS.

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
   # third party apps
    'django_extensions',
]

Now how to use django-envion's .env file which will pass INSTALLED_APPS

because i will have a different .env files for dev and prod

[ptink]

INSTALLED_APPS = [
    'django.contrib.admin',
    ...
] += env.list("ADDITIONAL_APPS", default=[])

dev.env

ADDITIONAL_APPS=devapp1,devapp2,devapp3

prod.env

ADDITIONAL_APPS=prodapp1,prodapp2,prodapp3

Personally INSTALLED_APPS is one of the things I leave to the dev.py / prod.py settings file patterns because the list order is sometimes important but this approach should work for you

[sant527]

Personally INSTALLED_APPS is one of the things I leave to the dev.py / prod.py

what does this mean. So how you do it then

[ptink]

what does this mean. So how you do it then

I have multiple settings files e.g. development.py, production.py, testing.py that all inherit from a base.py settings file. Common settings live in base.py and then dev/prod/testing settings files can override them as per that environments requirements.

see: https://medium.com/django-musings/the-multiple-settings-files-pattern-a6e6066d2a69

[sant527]

but then its better to have one settings.py and use django-environ and different .env files

[ptink]

That's up to you- I prefer a mix of approaches. I only use Django environ to keep sensitive information out of the repository and to read client-specific details from client.env files. Differences in app environments I leave up to separate settings.py files.

[joke2k]

@sant527 @ptink nice discussion,

I fought with this problem a lot of time and I tried always to keep one settings.py to avoid the inheritance of environment specific setting file.

If I can help you with this I suggest using something like ENV=prod or ENV=dev in the .env file, then into the settings.py you can use it to manage the INSTALLED_APPS list:

PRODUCTION = 'prod'
DEVELOPMENT = 'dev'

INSTALLED_APPS = [
    'django.contrib.admin',
    ...
]
if env.str('ENV') == DEVELOPMENT:
  INSTALLED_APPS.append('django_extensions')

in this way, we respecting the settings.py expertness about how to configure a Django application.

A side effect could be if you try to set ENV=dev in a production environment, which could not be found in the development packages. it depends on how to handle the requirements for different environments.

[sant527]

@joke2k
Thank you. I will use that way

what do you mean by

A side effect could be if you try to set ENV=dev in a production environment, which could not be found in the development packages.

[joke2k]

@sant527
is a common practice split requirements.txt by environments.
https://github.com/pydanny/cookiecutter-django/tree/master/%7B%7Bcookiecutter.project_slug%7D%7D/requirements

In this case, using my trick to fast exchange environment with .env ENV variable, you have to be sure that the INSTALLED_APPS are really installed.
Very common example: you could have django-debug-toolbar not installed in production, but changing ENV to dev you'll raise an error with this code in settings.py:

if env.str('ENV') == DEVELOPMENT:
  INSTALLED_APPS.append('debug_toolbar')