Question

I finally resolved the ubiquitous MySQL-python/OSX (10.7 64-bit) debacle and have Python and MySQL working fine by using 32-bit MySQL and calling python with ‘arch -i386’. Py scripts outside of Django are correctly querying MySQL etc. However, when I try to fire up Django and invoke the development server, I’m getting the error I was getting previously when using 64-bit Python:

django.core.exceptions.ImproperlyConfigured: Error loading MySQLdb module: dlopen(/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/_mysql.so, 2): no suitable image found.  Did find:
    /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/_mysql.so: mach-o, but wrong architecture

In my .bash_profile I have

alias python=’arch -i386 python2.7′

export VERSIONER_PYTHON_PREFER_64_BIT=no

export VERSIONER_PYTHON_PREFER_32_BIT=yes

So I don’t understand how Django is invoking python and why it isn’t honoring what I have in .bash_profile. What do I need to change in Django to get it to invoke 32-bit Python? The full traceback when I do ‘python manage.py runserver’ is:

Traceback (most recent call last):
  File "manage.py", line 14, in <module>
    execute_manager(settings)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 438, in execute_manager
    utility.execute()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 379, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 191, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 209, in execute
    translation.activate('en-us')
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/utils/translation/__init__.py", line 100, in activate
    return _trans.activate(language)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/utils/translation/trans_real.py", line 202, in activate
    _active.value = translation(language)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/utils/translation/trans_real.py", line 185, in translation
    default_translation = _fetch(settings.LANGUAGE_CODE)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/utils/translation/trans_real.py", line 162, in _fetch
    app = import_module(appname)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/utils/importlib.py", line 35, in import_module
    __import__(name)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/contrib/admin/__init__.py", line 3, in <module>
    from django.contrib.admin.helpers import ACTION_CHECKBOX_NAME
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/contrib/admin/helpers.py", line 3, in <module>
    from django.contrib.admin.util import (flatten_fieldsets, lookup_field,
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/contrib/admin/util.py", line 1, in <module>
    from django.db import models
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/__init__.py", line 78, in <module>
    connection = connections[DEFAULT_DB_ALIAS]
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/utils.py", line 93, in __getitem__
    backend = load_backend(db['ENGINE'])
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/utils.py", line 33, in load_backend
    return import_module('.base', backend_name)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/utils/importlib.py", line 35, in import_module
    __import__(name)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/mysql/base.py", line 14, in <module>
    raise ImproperlyConfigured("Error loading MySQLdb module: %s" % e)
django.core.exceptions.ImproperlyConfigured: Error loading MySQLdb module: dlopen(/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/_mysql.so, 2): no suitable image found.  Did find:
        /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/_mysql.so: mach-o, but wrong architecture

Answer 1

The VERSIONER_PYTHON_PREFER_32_BIT environment variable is an Apple-supplied feature. It only applies to the Apple-supplied system Pythons in Mac OS X 10.6 and 10.7. From the path shown, you are using a non-system Python (installed in /Library/Frameworks, possibly from a python.org installer). VERSIONER_PYTHON_PREFER_32_BIT will have no affect on it. Have you tried launching the development server with something like:

arch -i386 /usr/local/bin/python2.7 django-admin.py ...

You still may run into trouble if Django launches Python interpreters in subprocesses which will default to 64-bit. You should either get everything working in 64-bit mode or stick to a complete 32-bit chain of Python and MySQLdb. You could save yourself a lot of trouble by installing a complete solution from a third-party distributor like MacPorts or Homebrew.