Django debug toolbar import error of analysisdebug

问题:

Trying to install the django debug toolbar and receiving the following error:

Traceback (most recent call last):
  File "/home/user/project/manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
  File "/home/user/project/env/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 338, in execute_from_command_line
    utility.execute()
  File "/home/user/project/env/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 312, in execute
django.setup()
  File "/home/user/project/env/local/lib/python2.7/site-packages/django/__init__.py", line 18, in setup
apps.populate(settings.INSTALLED_APPS)
  File "/home/user/project/env/local/lib/python2.7/site-packages/django/apps/registry.py", line 85, in populate
app_config = AppConfig.create(entry)
  File "/home/user/project/env/local/lib/python2.7/site-packages/django/apps/config.py", line 86, in create
module = import_module(entry)
  File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module
__import__(name)
ImportError: No module named analysisdebug_toolbar

Package versions:

Django==1.8.2
django-debug-toolbar==1.3.0

Funny thing is this used to work but somehow broke due to some changes in the project.

回答1:

It looks like you are missing a comma in your INSTALLED_APPS setting.

Instead of:

INSTALLED_APPS = (
    ...
    'analysis'
    'debug_toolbar',
    ...
)

It should be:

INSTALLED_APPS = (
    ... 
    'analysis',
    'debug_toolbar',
    ...
)

When you forget the comma, Python concatonates 'analysis' and 'debug_toolbar' into the string analysisdebug_toolbar. In Python, it's a good idea to include a trailing comma in the last element in your list or tuple. It allows you to add new items or rearrange the order without hitting bugs like this.