Django 1.4.2 / South 0.7.6 database error - DEFAULT_DB_ALIAS

Question

When I run python manage.py runserver I get the following error:

Unhandled exception in thread started by <bound method Command.inner_run of <django.contrib.staticfiles.management.commands.runserver.Command object at 0x1cc9cd0>>
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/commands/runserver.py", line 91, in inner_run
    self.validate(display_num_errors=True)
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 266, in validate
    num_errors = get_validation_errors(s, app)
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/validation.py", line 30, in get_validation_errors
    for (app_name, error) in get_app_errors().items():
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/loading.py", line 158, in get_app_errors
    self._populate()
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/loading.py", line 64, in _populate
    self.load_app(app_name, True)
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/loading.py", line 88, in load_app
    models = import_module('.models', app_name)
  File "/usr/local/lib/python2.7/dist-packages/django/utils/importlib.py", line 35, in import_module
    __import__(name)
  File "/usr/local/lib/python2.7/dist-packages/South-0.7.6-py2.7.egg/south/models.py", line 2, in <module>
    from south.db import DEFAULT_DB_ALIAS
  File "/usr/local/lib/python2.7/dist-packages/South-0.7.6-py2.7.egg/south/db/__init__.py", line 81, in <module>
    db = dbs[DEFAULT_DB_ALIAS]
KeyError: 'default'

Here is my settings.py:

 DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql_psycopg2',
        'NAME': 'foureggs',
        'USER': 'myuser',
        'PASSWORD': 'mypass',
        'HOST': '',
        'PORT': '',
    }
}

Here is a question with the same problem. The answer says that "there should be a database named 'default' in your settings". I'm not really following that. My db name is "foureggs" so I want to use that, obviously.

UPDATE: When I do python manage.py diffsettings I get the following output, which doesn't look correct (pasting only the relevant DATABASE line, the rest of the settings look OK):

DATABASES = {'default': {'ENGINE': 'django.db.backends.dummy', 'TEST_MIRROR': None, 'NAME': '', 'TEST_CHARSET': None, 'TIME_ZONE': 'UTC', 'TEST_COLLATION': None, 'PORT': '', 'HOST': '', 'USER': '', 'TEST_NAME': None, 'PASSWORD': '', 'OPTIONS': {}}}

I have only one settings file in my project and it's in the app directory, which is correct. Where does the above DATABASE line come from?

UPDATE 2: I figured out what's the problem. It's these 2 extra lines I put to settings.py as instructed by Heroku deployment guide. When I comment them out, everything works fine. Now I need to figure out why it's causing the problem.

# Parse database configuration from $DATABASE_URL
import dj_database_url
DATABASES['default'] =  dj_database_url.config()

which version of Django are you using? (python -c "import django; print django.VERSION") — furins, Jan 27 '13 at 10:00
if you remove south from your installed apps does the runserver command fail? (or: has it worked before/have you called a syncdb?) — furins, Jan 27 '13 at 10:30
@furins It runs fine if I comment out south in the installed apps. — finspin, Jan 27 '13 at 10:32
ps. in the question you mentioned when they suggest a database named "default" they meant the name of the dictionary key, not of the db. your settings are ok, no need to rename anything :) — furins, Jan 27 '13 at 10:32
ok, just for testing purposes, can you try to run the command "python ./manage.py syncdb" and see if any error/change in the db will be reported? — furins, Jan 27 '13 at 10:34
@furins Yes, it gives me this error: http://dpaste.com/893587/ — finspin, Jan 27 '13 at 10:38

score 2 · Answer 1 · answered Feb 26 '13 at 18:23

I solved this by setting the Heroku config like this instead:

# Parse database configuration from $DATABASE_URL
import dj_database_url

dbconfig = dj_database_url.config()
if dbconfig:
    DATABASES['default'] =  dbconfig

# Honor the 'X-Forwarded-Proto' header for request.is_secure()
SECURE_PROXY_SSL_HEADER = ('HTTP_X_FORWARDED_PROTO', 'https')

score 1 · Answer 2 · answered Jan 27 '13 at 19:41

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql_psycopg2',
        'NAME': 'foureggs',
        'USER': 'myuser',
        'PASSWORD': 'mypass',
        'HOST': '',
        'PORT': '',
    }
}

You need to fill in the HOST and the PORT otherwise django doesn't know where your database server is. Only if you are using sqlite can those be empty.

For postgreql, the default port is 5432. If you are running the server on the same machine, use 'localhost' for the 'HOST' key, otherwise put in the IP address of your database server.

score 1 · Answer 3 · answered Oct 23 '13 at 13:42

In my case, i was working on development environment (MY LAPTOP) where these were my dev settings when i got the error

import dj_database_url
DATABASES['default'] =  dj_database_url.config()

if not os.environ.has_key('DATABASE_URL'):
     os.environ['DATABASE_URL'] = 'postgres://my_db:my_db@localhost/my_db'

Later on I changed it to this and things started working fine

if not os.environ.has_key('DATABASE_URL'):
         os.environ['DATABASE_URL'] = 'postgres://my_db:my_db@localhost/my_db'

import dj_database_url
    DATABASES['default'] =  dj_database_url.config()

dj_database_url.config() function call needs DATABASE_URL to be initialized

score 0 · Accepted Answer · edited May 23 '17 at 11:56

The problem is apparently not related to South, but to the DB backend.

you may start from here: "settings.DATABASES is improperly configured" error performing syncdb with django 1.4 and related questions
If the aforementioned answers not work, first of all check if psycopg2 library is installed and in your sys.path: if not please install it Psycopg2 library install instructions here.
then you can eventually change your ENGINE setting to: 'postgresql_psycopg2'; in this way you can bypass the built-in engine if for any reason it will not work.

score 0 · Answer 5 · answered Apr 07 '14 at 01:41

I had this problem after following the Heroku instructions. You are correct that these lines are the culprit:

# Parse database configuration from $DATABASE_URL
import dj_database_url
DATABASES['default'] =  dj_database_url.config()

This switches the DATABASES values back to the defaults used by the dj_database_url package, which has the engine "django.db.backends.dummy", etc. If you swap this in for those lines, it should work:

# Parse database configuration from $DATABASE_URL
import dj_database_url
DATABASES['default'] = dj_database_url.config(default='postgres://localhost/foureggs')

HOWEVER, you don't want to deploy this to Heroku, as it won't work there. The fix I found assumes that you're using virtual environments. If so, navigate to the folder of your virtual env and into the bin directory (cd $VIRTUAL_ENV/bin), add a file called "postactivate" and save this line in it:

export DATABASE_URL='postgres://localhost/foureggs'

Now every time you activate the virtual environment, it will start with that value.

Django 1.4.2 / South 0.7.6 database error - DEFAULT_DB_ALIAS

5 Answers5