Django Gunicorn：調用元類基礎時出錯

Question

我有一個Django應用程序，其中包括一個自定義模型字段（以及隨附的表單字段）。 當我使用內置的開發服務器運行項目時，它可以正常工作。 但是，用gunicorn加載服務器會導致以下錯誤：

TemplateSyntaxError at /admin/
Caught TypeError while rendering: Error when calling the metaclass bases
    must be type, not None

為了完整起見，我在下面包括了整個錯誤，該錯誤顯示了錯誤所在的行：

Traceback:
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  111.                         response = callback(request, *callback_args, **callback_kwargs)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/contrib/admin/sites.py" in wrapper
  214.                 return self.admin_view(view, cacheable)(*args, **kwargs)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view
  93.                     response = view_func(request, *args, **kwargs)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/views/decorators/cache.py" in _wrapped_view_func
  79.         response = view_func(request, *args, **kwargs)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/contrib/admin/sites.py" in inner
  197.             return view(request, *args, **kwargs)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/views/decorators/cache.py" in _wrapped_view_func
  79.         response = view_func(request, *args, **kwargs)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/contrib/admin/sites.py" in index
  382.             context_instance=context_instance
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/shortcuts/__init__.py" in render_to_response
  20.     return HttpResponse(loader.render_to_string(*args, **kwargs), **httpresponse_kwargs)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/loader.py" in render_to_string
  188.         return t.render(context_instance)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/base.py" in render
  123.             return self._render(context)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/base.py" in _render
  117.         return self.nodelist.render(context)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/base.py" in render
  744.                 bits.append(self.render_node(node, context))
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/debug.py" in render_node
  73.             result = node.render(context)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/loader_tags.py" in render
  127.         return compiled_parent._render(context)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/base.py" in _render
  117.         return self.nodelist.render(context)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/base.py" in render
  744.                 bits.append(self.render_node(node, context))
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/debug.py" in render_node
  73.             result = node.render(context)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/loader_tags.py" in render
  127.         return compiled_parent._render(context)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/base.py" in _render
  117.         return self.nodelist.render(context)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/base.py" in render
  744.                 bits.append(self.render_node(node, context))
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/debug.py" in render_node
  73.             result = node.render(context)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/defaulttags.py" in render
  311.             return self.nodelist_true.render(context)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/base.py" in render
  744.                 bits.append(self.render_node(node, context))
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/debug.py" in render_node
  73.             result = node.render(context)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/defaulttags.py" in render
  311.             return self.nodelist_true.render(context)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/base.py" in render
  744.                 bits.append(self.render_node(node, context))
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/debug.py" in render_node
  73.             result = node.render(context)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/loader_tags.py" in render
  64.             result = block.nodelist.render(context)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/base.py" in render
  744.                 bits.append(self.render_node(node, context))
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/debug.py" in render_node
  73.             result = node.render(context)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/template/defaulttags.py" in render
  437.             url = reverse(view_name, args=args, kwargs=kwargs, current_app=context.current_app)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/core/urlresolvers.py" in reverse
  391.             *args, **kwargs)))
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/core/urlresolvers.py" in reverse
  312.         possibilities = self.reverse_dict.getlist(lookup_view)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/core/urlresolvers.py" in _get_reverse_dict
  229.             self._populate()
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/core/urlresolvers.py" in _populate
  208.                     for name in pattern.reverse_dict:
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/core/urlresolvers.py" in _get_reverse_dict
  229.             self._populate()
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/core/urlresolvers.py" in _populate
  208.                     for name in pattern.reverse_dict:
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/core/urlresolvers.py" in _get_reverse_dict
  229.             self._populate()
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/core/urlresolvers.py" in _populate
  197.         for pattern in reversed(self.url_patterns):
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/core/urlresolvers.py" in _get_url_patterns
  279.         patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/core/urlresolvers.py" in _get_urlconf_module
  274.             self._urlconf_module = import_module(self.urlconf_name)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/utils/importlib.py" in import_module
  35.     __import__(name)
File "/home/rob/projects/shipp/shipp/tickets/urls.py" in <module>
  3. from shipp.tickets.views import TicketListView, TicketDetailView, \
File "/home/rob/projects/shipp/shipp/tickets/views.py" in <module>
  15. from shipp.tickets.forms import TicketForm, TicketAttributesForm, \
File "/home/rob/projects/shipp/shipp/tickets/forms.py" in <module>
  26. class TicketTimeSpentForm(forms.ModelForm):
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/forms/models.py" in __new__
  205.                                       opts.exclude, opts.widgets, formfield_callback)
File "/home/rob/.virtualenvs/shipp/lib/python2.7/site-packages/django/forms/models.py" in fields_for_model
  159.             formfield = f.formfield(**kwargs)
File "/home/rob/projects/shipp/shipp/../shipp/tickets/fields.py" in formfield
  43.         return super(TimedeltaField, self).formfield(*args, **defaults)

Exception Type: TemplateSyntaxError at /admin/
Exception Value: Caught TypeError while rendering: Error when calling the metaclass bases
    must be type, not None

從回溯中可以看到，引起問題的行（ fields.py第43 fields.py ）只是常規的super調用。 您對為什么會發生此錯誤有任何想法嗎？ 如果我刪除導致上述問題的方法，它也會在其他地方發生。

Answer 1

這是由於我們嘗試重新加載Django時Gunicorn中的錯誤所致。 此后已恢復，應固定在主節點上。 我們目前正在研究一種替代方法，以使run_gunicorn命令可以重新加載。 您可以在此處關注其進度：

https://github.com/benoitc/gunicorn/issues/222