RuntimeError: Model class django.contrib.sites.models.Site doesn't declare an explicit app_label and isn't in an application in INSTALLED_APPS

I am building an application with Django Rest Framework and AngularJs. I am using Django-rest-auth for my authentication purposes, although, I have not been able to set it up. Anyway, I am trying to set up this app with my project. I realized I need to install django-rest-auth-registration to get it running, so I followed this documentation to do the following things:

I ran the commands

> pip install django-rest-auth

and

> pip install django-allauth

Any my settings.py looks like this:

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',

    # 3rd party apps
    'rest_framework',
    'rest_framework.authtoken',
    'rest_auth',
    'allauth',
    'allauth.account',
    'rest_auth.registration',

    # My app
    'myapp',
]

I have also added the authentication backends, context_processors, and the proper urls.

However, when I try to migrate, my terminal throws the following error:

> RuntimeError: Model class django.contrib.sites.models.Site doesn't > declare an explicit app_label and isn't in an application in > INSTALLED_APPS.

Why do I get this error, and how do I solve it to migrate my project? Thanks!

The fix

Just add Django's Sites framework to your apps and set SITE_ID to 1 in your settings.

INSTALLED_APPS = [
    ...
    'django.contrib.sites',
]

SITE_ID = 1

Why does this happen?

Django's Sites Framework is a contributed module bundled with the core library that allows for the use of a single Django application/codebase with different sites (that can use different databases, logic in views, etc). The SITE_ID setting, as stated in the docs, "is used so that application data can hook into specific sites and a single database can manage content for multiple sites."

In this particular case AllAuth requires the Sites Framework in order to function properly. Many other third-party libraries are built to safely handle cases where multiple sites may be present and as such may be best .

I landed on this post via Google search. My problem was running tests that blew up with the error:

RuntimeError: Model class app.taxonomy.models.Term doesn't declare an explicit app_label and isn't in an application in INSTALLED_APPS.

This was running on Python 2.7.x with absolute imports. As mentioned by Colton Hicks in the comments, below, this can also happen with Python 3 (pytest 3.2.3 with Django 1.11.4).

In my tests.py:

from __future__ import absolute_import
[...]
from .models import Demographics, Term

After changing the relative import to an absolute import the problem went away:

from taxonomy.models import Demographics, Term

HTH

I got the error above. However my problem was the in the urls.py. I was following PyDanny cookiecutter django recipe. My error was to put in the urls.py this line:

    url(r'^demo/', include('project.demoapp.urls', namespace='demoapp')),

when I corrected to this:

    url(r'^demo/', include('demoapp.urls', namespace='demoapp')),

all was well. I also changed my local apps (I did this first and so the critical error was the url misconfiguration):

LOCAL_APPS = [
    # Your stuff: custom apps go here
    'demoapp.apps.DemoAppConfig',
]

Just add 'django.contrib.sites', to INSTALLED_APPS and set SITE_ID = 1 in your settings.py file.

Try adding the app_label = 'yourApp' in the models Meta class:

class Meta:

    app_label = 'yourApp'

I have django debug toolbar installed and this was actually causing the/my problem. INSTALLED_APPS (in settings.py) needs the entry 'django.contrib.sessions'. Make sure to run migrate after adding.