def get_cache(backend, **kwargs):
"""
Function to load a cache backend dynamically. This is flexible by design
to allow different use cases:
To load a backend with the old URI-based notation::
cache = get_cache('locmem://')
To load a backend that is pre-defined in the settings::
cache = get_cache('default')
To load a backend with its dotted import path,
including arbitrary options::
cache = get_cache('torngas.cache.backends.memcached.MemcachedCache', **{
'LOCATION': '127.0.0.1:11211', 'TIMEOUT': 30,
})
"""
try:
backend, location, params = parse_backend_conf(backend, **kwargs)
mod_path, cls_name = backend.rsplit('.', 1)
mod = import_object(mod_path)
backend_cls = getattr(mod, cls_name)
except (AttributeError, ImportError) as e:
raise InvalidCacheBackendError("Could not find backend '%s': %s" %
(backend, e))
cache = backend_cls(location, params)
# Some caches -- python-memcached in particular -- need to do a cleanup at the
# end of a request cycle. If the cache provides a close() method, wire it up
# here.
if hasattr(cache, 'close'):
signals.call_finished.connect(cache.close)
if hasattr(cache, 'clear_expires'):
# signals.call_finished.connect(cache.clear_expires)
#every half an hour,clear expires cache items
PeriodicCallback(cache.clear_expires, 1000 * 1800).start()
return cache
def parse_backend_conf(backend, **kwargs):
"""
Helper function to parse the backend configuration
that doesn't use the URI notation.
"""
# Try to get the CACHES entry for the given backend name first
conf = settings_helper.settings.CACHES.get(backend, None)
if conf is not None:
args = conf.copy()
args.update(kwargs)
backend = args.pop('BACKEND')
location = args.pop('LOCATION', '')
return backend, location, args
else:
try:
# Trying to import the given backend, in case it's a dotted path
mod_path, cls_name = backend.rsplit('.', 1)
mod = import_object(mod_path)
backend_cls = getattr(mod, cls_name)
except (AttributeError, ImportError, ValueError):
raise InvalidCacheBackendError("Could not find backend '%s'" %
backend)
location = kwargs.pop('LOCATION', '')
return backend, location, kwargs