缓存后端在devserver上工作,但不是mod wsgi

我正在使用自定义缓存后端来包装内置缓存后端,以便将当前站点ID添加到所有缓存密钥中(这对于具有单个memcached实例的多站点功能很有用)

不幸的是,它在Django内置的devserver上运行得很好,但是当我尝试在带有mod_wsgi的实时服务器上运行它时,会出现严重的错误。

以下是我的错误日志的回溯:

[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1] mod_wsgi (pid=22933): Exception occurred processing WSGI script '/home/jiaaro/webapps/op_wsgi/myProject/deploy/myProject.wsgi'.
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1] Traceback (most recent call last):
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1]   File "/home/jiaaro/webapps/op_wsgi/lib/python2.5/django/core/handlers/wsgi.py", line 230, in __call__
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1]     self.load_middleware()
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1]   File "/home/jiaaro/webapps/op_wsgi/lib/python2.5/django/core/handlers/base.py", line 40, in load_middleware
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1]     mod = import_module(mw_module)
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1]   File "/home/jiaaro/webapps/op_wsgi/lib/python2.5/django/utils/importlib.py", line 35, in import_module
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1]     __import__(name)
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1]   File "/home/jiaaro/webapps/op_wsgi/myProject/apps/site_settings/__init__.py", line 6, in <module>
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1]     import cache_wrapper
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1]   File "/home/jiaaro/webapps/op_wsgi/myProject/apps/site_settings/cache_wrapper.py", line 4, in <module>
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1]     from django.core.cache.backends.base import BaseCache
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1]   File "/home/jiaaro/webapps/op_wsgi/lib/python2.5/django/core/cache/__init__.py", line 73, in <module>
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1]     cache = get_cache(settings.CACHE_BACKEND)
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1]   File "/home/jiaaro/webapps/op_wsgi/lib/python2.5/django/core/cache/__init__.py", line 68, in get_cache
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1]     return getattr(module, 'CacheClass')(host, params)
[Wed Feb 17 00:39:34 2010] [error] [client 127.0.0.1] AttributeError: 'module' object has no attribute 'CacheClass'

如果我在同一台机器(实时服务器)上运行devserver,它会正常工作…我可以毫不费力地做到这一点:

$ cd /home/jiaaro/webapps/op_wsgi/myProject
$ python2.5 manage.py runserver

在单独的ssh会话中…

$ wget 127.0.0.1:8000

使用memcached和实时数据库正确地提供页面。mod wsgi导入模块的方式有什么不同吗?

也许是关于devserver的单进程、单线程的特性?

我已经为此苦苦挣扎了好几天了,任何帮助都会得到感激的。

额外信息:

• 网络派系共享托管(CentOS)
• Apache 2
• 巨蟒2.5
• Django1.1.1
• MODYWSGI 2.5
• MySQL 5

更多细节: -我已经设置了缓存后端(它正在工作,因为您可以看到它在回溯中导入了正确的模块) -模块中有一个名为“cacheClass”的类:

站点设置/缓存包装:

from django.conf import settings
CACHE_BACKEND = getattr(settings, 'CUSTOM_CACHE_BACKEND')

from django.core.cache.backends.base import BaseCache

class CacheClass(BaseCache):
    from decorators import accept_site

    def __init__(self, *args):
        from django.core.cache import get_cache
        self.WRAPPED_CACHE = get_cache(CACHE_BACKEND)

    @accept_site
    def add(self, site, key, *args):
        return self.WRAPPED_CACHE.add(self._key(site, key),*args)

    @accept_site
    def get(self, site, key, *args):
        return self.WRAPPED_CACHE.get(self._key(site, key),*args)

    ... (all the rest of the wrapped methods)

    def _key(self, site, key):
        from exceptions import NoCurrentSite
        if not site:
            raise NoCurrentSite
        return "%s|%s" % (site.id, key)

accept-site修饰器与一些中间件一起工作,以确定当前站点。它们在这里:

装饰:

def accept_site(fn):
    def decorator(self, *args, **kwargs):
        site = kwargs.get('site', None)
        try: 
            del kwargs['site']
        except KeyError: 
            pass

        from .middleware import get_current_site
        site = site or get_current_site()

        if not site:
            raise NoCurrentSite("The current site is not available via thread locals, please specify a site with the 'site' keyword argument")

        return fn(self, site, *args, **kwargs)

    return decorator

和中间件.py

try:
    from threading import local
except ImportError:
    from django.utils._threading_local import local

from django.conf import settings
from django.contrib.sites.models import Site

DEFAULT_SITE_ID = 1

_thread_locals = local()
def get_current_site():
    return getattr(_thread_locals, 'site', None)

def set_current_site(site):
    setattr(_thread_locals, 'site', site)

class SiteSettings(object):
    """Middleware that gets various objects from the
    request object and saves them in thread local storage."""
    def process_request(self, request):
        if settings.DEBUG:
            site_id = request.GET.get('site_id', DEFAULT_SITE_ID)
        else:
            site_id = DEFAULT_SITE_ID

        current_site_domain = request.META["HTTP_HOST"]
        try:
            current_site = Site.objects.get(domain__iexact=current_site_domain())
        except:
            current_site = Site.objects.get(id=site_id)
        set_current_site(current_site)

所有这些都使用devserver,使用与wsgi服务器相同的设置,并使用相同的python路径进行配置(据我所见)

现在,我希望我已经在某个地方创建了一个导入循环(尽管这并不能说明它只发生在devserver中)。

编辑: 我发现了一个 list of the differences between devserver and apache 在Django的文档中,

devserver将已安装的应用程序添加到 sys.path,apache没有。

也许这和它有关?