def configure(self,
backend,
expiration_time=None,
arguments=None,
_config_argument_dict=None,
_config_prefix=None):
"""Configure a :class:`.CacheRegion`.
The :class:`.CacheRegion` itself
is returned.
:param backend: Required. This is the name of the
:class:`.CacheBackend` to use, and is resolved by loading
the class from the ``dogpile.cache`` entrypoint.
:param expiration_time: Optional. The expiration time passed
to the dogpile system. The :meth:`.CacheRegion.get_or_create`
method as well as the :meth:`.CacheRegion.cache_on_arguments`
decorator (though note: **not** the :meth:`.CacheRegion.get`
method) will call upon the value creation function after this
time period has passed since the last generation.
:param arguments: Optional. The structure here is passed
directly to the constructor of the :class:`.CacheBackend`
in use, though is typically a dictionary.
"""
if "backend" in self.__dict__:
raise Exception("This region is already "
"configured with backend: %s" % self.backend)
backend_cls = _backend_loader.load(backend)
if _config_argument_dict:
self.backend = backend_cls.from_config_dict(
_config_argument_dict, _config_prefix)
else:
self.backend = backend_cls(arguments or {})
self.expiration_time = expiration_time
if self.key_mangler is None:
self.key_mangler = self.backend.key_mangler
self._lock_registry = NameRegistry(self._create_mutex)
return self
def configure(
self,
backend,
expiration_time=None,
arguments=None,
_config_argument_dict=None,
_config_prefix=None,
wrap=None,
replace_existing_backend=False,
):
"""Configure a :class:`.CacheRegion`.
The :class:`.CacheRegion` itself
is returned.
:param backend: Required. This is the name of the
:class:`.CacheBackend` to use, and is resolved by loading
the class from the ``dogpile.cache`` entrypoint.
:param expiration_time: Optional. The expiration time passed
to the dogpile system. May be passed as an integer number
of seconds, or as a ``datetime.timedelta`` value.
.. versionadded 0.5.0
``expiration_time`` may be optionally passed as a
``datetime.timedelta`` value.
The :meth:`.CacheRegion.get_or_create`
method as well as the :meth:`.CacheRegion.cache_on_arguments`
decorator (though note: **not** the :meth:`.CacheRegion.get`
method) will call upon the value creation function after this
time period has passed since the last generation.
:param arguments: Optional. The structure here is passed
directly to the constructor of the :class:`.CacheBackend`
in use, though is typically a dictionary.
:param wrap: Optional. A list of :class:`.ProxyBackend`
classes and/or instances, each of which will be applied
in a chain to ultimately wrap the original backend,
so that custom functionality augmentation can be applied.
.. versionadded:: 0.5.0
.. seealso::
:ref:`changing_backend_behavior`
:param replace_existing_backend: if True, the existing cache backend
will be replaced. Without this flag, an exception is raised if
a backend is already configured.
.. versionadded:: 0.5.7
"""
if "backend" in self.__dict__ and not replace_existing_backend:
raise exception.RegionAlreadyConfigured(
"This region is already "
"configured with backend: %s. "
"Specify replace_existing_backend=True to replace." %
self.backend)
backend_cls = _backend_loader.load(backend)
if _config_argument_dict:
self.backend = backend_cls.from_config_dict(
_config_argument_dict, _config_prefix)
else:
self.backend = backend_cls(arguments or {})
if not expiration_time or isinstance(expiration_time, Number):
self.expiration_time = expiration_time
elif isinstance(expiration_time, datetime.timedelta):
self.expiration_time = int(
compat.timedelta_total_seconds(expiration_time))
else:
raise exception.ValidationError(
'expiration_time is not a number or timedelta.')
if not self._user_defined_key_mangler:
self.key_mangler = self.backend.key_mangler
self._lock_registry = NameRegistry(self._create_mutex)
if getattr(wrap, '__iter__', False):
for wrapper in reversed(wrap):
self.wrap(wrapper)
return self
