libmysqlclient.18.dylib image not found when using MySQL from Django on OS X

Question

I'm starting down the path of learning Python/Django and have hit my first snag. When attempting to set my database in settings.py, the internal server fails with:

File "/Library/Python/2.7/site-packages/django/db/backends/mysql/base.py", line 16, in <module>
raise ImproperlyConfigured("Error loading MySQLdb module: %s" % e)
django.core.exceptions.ImproperlyConfigured: Error loading MySQLdb module: dlopen(/Users/rob/.python-eggs/MySQL_python-1.2.3-py2.7-macosx-10.7-intel.egg-tmp/_mysql.so, 2): Library not loaded: libmysqlclient.18.dylib
Referenced from: /Users/rob/.python-eggs/MySQL_python-1.2.3-py2.7-macosx-10.7-intel.egg-tmp/_mysql.so
Reason: image not found

There are a lot of solutions that I've found, mostly involving the explicit definition of my DYLD_LIBRARY_PATH value, but that doesn't work for me. MysQL-Python is installed (v1.2.3).

Any idea what I might need to do to push through this?

Thanks.

UPDATE

DATABASES = {
  'default': {
    'ENGINE': 'django.db.backends.mysql',  # Add 'postgresql_psycopg2', 'mysql', 'sqlite3' or 'oracle'.
    'NAME': 'django_tutorial',                      # Or path to database file if using sqlite3.
    'USER': 'root',                      # Not used with sqlite3.
    'PASSWORD': '',                  # Not used with sqlite3.
    'HOST': '',                      # Set to empty string for localhost. Not used with sqlite3.
    'PORT': '',                      # Set to empty string for default. Not used with sqlite3.
  }
}

Answer 1

From your comments, it appears that the libmysqlclient dylib was installed with a non-absolute library name path. That's contrary to standard practice on OS X which is different from most other Unix-y systems in this respect. You should be able to permanently fix the problem (at least until your next upgrade) by modifying the path in the .so file by using install_name_tool or you can make it work by ensuring your Django instance is running with the following environment variable defined:

export DYLD_LIBRARY_PATH=/usr/local/mysql/lib

You also might be able to get it to work by creating a symlink in /usr/local/lib to the dylib in /usr/local/mysql/lib since /usr/local/lib is on the default dynamic load search path, so (untested!) something like:

sudo ln -s /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/local/lib/libmysqlclient.18.dylib

A better long-term solution is to not use a broken MySQL client installation as suggested in Python import MySQLdb error - Mac 10.6.

Answer 2

Using a homebrew installation of mysql, this worked for me:

$ mdfind libmysqlclient
/usr/local/Cellar/mysql/5.7.9/lib/libmysqlclient.20.dylib
/usr/local/Cellar/mysql/5.7.9/lib/libmysqlclient.a
/usr/local/Cellar/mysql/5.6.27/lib/libmysqlclient.18.dylib
/usr/local/Cellar/mysql/5.6.27/lib/libmysqlclient.a
/usr/local/Cellar/mysql/5.6.26/lib/libmysqlclient.18.dylib
/usr/local/Cellar/mysql/5.6.26/lib/libmysqlclient.a

$ sudo ln -s /usr/local/Cellar/mysql/5.6.27/lib/libmysqlclient.18.dylib /usr/local/lib/libmysqlclient.18.dylib