python - Django: AppRegistryNotReady()

Question

Python: 2.7; Django: 1.7; Mac 10.9.4

I'm following the tutorial of Tango with Django

At Chapter 5, the tutorial teaches how to create a population script, which can automatically create some data for the database for the ease of development.

I created a populate_rango.py at the same level of manage.py.

Here's the populate_rango.py:

import os

def populate():
    python_cat = add_cat('Python')

    add_page(
        cat=python_cat,
        title="Official Python Tutorial",
        url="http://docs.python.org/2/tutorial/"
    )

    add_page(
        cat=python_cat,
        title="How to Think like a Computer Scientist",
        url="http://www.greenteapress.com/thinkpython/"
    )

    add_page(
        cat=python_cat,
        title="Learn Python in 10 Minutes",
        url="http://www.korokithakis.net/tutorials/python/"
    )

    django_cat = add_cat("Django")

    add_page(
        cat=django_cat,
        title="Official Django Tutorial",
        url="https://docs.djangoproject.com/en/1.5/intro/tutorial01/"
    )

    add_page(
        cat=django_cat,
        title="Django Rocks",
        url="http://www.djangorocks.com/"
    )

    add_page(
        cat=django_cat,
        title="How to Tango with Django",
        url="http://www.tangowithdjango.com/"
    )

    frame_cat = add_cat("Other Frameworks")

    add_page(
        cat=frame_cat,
        title="Bottle",
        url="http://bottlepy.org/docs/dev/"
    )

    add_page(
        cat=frame_cat,
        title="Flask",
        url="http://flask.pocoo.org"
    )

    for c in Category.objects.all():
        for p in Page.objects.filter(category=c):
            print "- {0} - {1}".format(str(c), str(p))


def add_page(cat, title, url, views=0):
    p = Page.objects.get_or_create(category=cat, title=title, url=url, views=views)[0]
    return p


def add_cat(name):
    c = Category.objects.get_or_create(name=name)[0]
    return c

if __name__ == '__main__':
    print "Starting Rango population script..."
    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'tangle.settings')
    from rango.models import Category, Page
    populate()

Then I run python populate_rango.py at the terminal at the level of manage.py, AppRegistryNotReady() is raised:

django.core.exceptions.AppRegistryNotReady

Then I googled it, found something like this:

Standalone scripts?
If you’re using Django in a plain Python script — rather than a management command — and you rely on the DJANGO_SETTINGS_MODULE environment variable, you must now explicitly initialize Django at the beginning of your script with:

>>> import django
>>> django.setup()
Otherwise, you will hit an AppRegistryNotReady exception.

And I still have no idea what should I do, can some one help? Thx!!!

Answer 1

If you are using your django project applications in standalone scripts, in other words, without using manage.py - you need to manually call django.setup() first - it would configure the logging and, what is important - populate apps registry.

Quote from Initialization process docs:

setup()

This function is called automatically:

• When running an HTTP server via Django’s WSGI support.

• When invoking a management command.

It must be called explicitly in other cases, for instance in plain Python scripts.

In your case, you need to call setup() manually:

if __name__ == '__main__':
    print "Starting Rango population script..."
    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'tangle.settings')

    import django
    django.setup()

    populate()

Also, this problem is described in detail in Troubleshooting section.