我一直在用WSGI开发部署在Apache服务器上的Django web应用程序，一切都进展顺利.今天，为了定制内置的Django管理界面，我对我的应用程序的admin.py做了一些小改动，最初出现了一个语法错误(未闭合的括号).这意味着，当我touch wsgi.py并加载代码时(我的虚拟主机上以守护程序模式运行WSGI)，我的网站被替换为一个内部服务器错误，因为WSGI在遇到语法错误时停止.
因此，我修复了语法错误，使用manage.py check判断了没有更多的错误，并触及wsgi.py进行重新部署.但是我的网站仍然显示内部服务器错误！判断Apache日志(log)，我看到的是:
[Sun Nov 23 13:52:46 2014] [info] mod_wsgi (pid=19093): Create interpreter 'quotes.cs.cornell.edu|'.
[Sun Nov 23 13:52:46 2014] [info] mod_wsgi (pid=19093): Adding '/extra/www/html/quotes/quotes_django' to path.
[Sun Nov 23 13:52:46 2014] [info] mod_wsgi (pid=19093): Adding '/opt/rh/python27/root/usr/lib64/python2.7/site-
packages/' to path.
[Sun Nov 23 13:52:46 2014] [info] [client 128.84.33.19] mod_wsgi (pid=19093, process='quotes.cs.cornell.edu',
application='quotes.cs.cornell.edu|'): Loading WSGI script '/extra/www/html/quotes/quotes_django/quotes_django/
wsgi.py'.
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] mod_wsgi (pid=19093): Target WSGI script '/extra/www/html/
quotes/quotes_django/quotes_django/wsgi.py' cannot be loaded as Python module.
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] mod_wsgi (pid=19093): Exception occurred processing WSGI
script '/extra/www/html/quotes/quotes_django/quotes_django/wsgi.py'.
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] Traceback (most recent call last):
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/extra/www/html/quotes/quotes_django/
quotes_django/wsgi.py", line 14, in <module>
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] application = get_wsgi_application()
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site-
packages/django/core/wsgi.py", line 14, in get_wsgi_application
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] django.setup()
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site-
packages/django/__init__.py", line 21, in setup
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] apps.populate(settings.INSTALLED_APPS)
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site-
packages/django/apps/registry.py", line 115, in populate
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] app_config.ready()
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site-
packages/django/contrib/admin/apps.py", line 22, in ready
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] self.module.autodiscover()
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site-
packages/django/contrib/admin/__init__.py", line 23, in autodiscover
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] autodiscover_modules('admin', register_to=site)
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site-
packages/django/utils/module_loading.py", line 74, in autodiscover_modules
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] import_module('%s.%s' % (app_config.name,
module_to_search))
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/usr/lib64/python2.7/importlib/__init__.py", line
37, in import_module
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] __import__(name)
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/extra/www/html/quotes/quotes_django/quotespage/
admin.py", line 25
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] approve_quotes.short_description = "Approve selected
quotes"
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] ^
[Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] SyntaxError: invalid syntax
[Sun Nov 23 13:53:36 2014] [info] [client 128.84.33.19] mod_wsgi (pid=19093, process='quotes.cs.cornell.edu',
application='quotes.cs.cornell.edu|'): Loading WSGI script '/extra/www/html/quotes/quotes_django/quotes_django/
wsgi.py'.
[Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] mod_wsgi (pid=19093): Target WSGI script '/extra/www/html/
quotes/quotes_django/quotes_django/wsgi.py' cannot be loaded as Python module.
[Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] mod_wsgi (pid=19093): Exception occurred processing WSGI
script '/extra/www/html/quotes/quotes_django/quotes_django/wsgi.py'.
[Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] Traceback (most recent call last):
[Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] File "/extra/www/html/quotes/quotes_django/
quotes_django/wsgi.py", line 14, in <module>
[Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] application = get_wsgi_application()
[Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site-
packages/django/core/wsgi.py", line 14, in get_wsgi_application
[Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] django.setup()
[Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site-
packages/django/__init__.py", line 21, in setup
[Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] apps.populate(settings.INSTALLED_APPS)
[Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site-
packages/django/apps/registry.py", line 78, in populate
[Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] raise RuntimeError("populate() isn't reentrant")
[Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] RuntimeError: populate() isn't reentrant
第一系列错误显示WSGI由于我的admin.py中的语法错误而失败.但是，第二系列错误似乎显示了Django内部的错误:
RuntimeError: populate() isn't reentrant
从registry.py的populate方法抛出.
谷歌搜索此错误消息返回的信息少得令人惊讶，这些信息都不是来自Django文档.显然，如果你在settings.py个应用中给一个应用命名两次，这种情况有时会发生，但我不会这么做.更重要的是，自从网站正常运行以来，我没有更改过settings.py--我唯一更改的是admin.py.
我try 恢复我所做的所有更改，所以我的所有Python代码都回到了网站运行时的状态--当我试图让WSGI重新加载代码时，我仍然得到populate() isn't reentrant错误！
我也试过在settings.py的installed_apps部分注释掉不同的应用程序，即使只启用了‘django.contri.staticfiles’，错误仍然会发生.奇怪的是，即使我注释掉all个应用程序，我仍然收到错误--Django即使没有加载任何应用程序也会抛出错误！
有人知道这里发生了什么吗？或者有没有更好的方法来调试这个错误，因为Apache日志(log)中的回溯非常没有帮助？
注意:我使用的是Django 1.7、Apache 2.2和Python 2.7.