Fixed #20892 -- Allowed configuring memcached client using OPTIONS.

Previously, the MemcachedCache backend ignored `OPTIONS` and
PyLibMCCache used them to set pylibmc behaviors. Both backends now
pass `OPTIONS` as keyword arguments to the client constructors.
This commit is contained in:
Ed Morley 2016-08-31 13:12:40 +01:00 committed by Tim Graham
parent 1d54fb4483
commit 65ec8fa8ca
6 changed files with 120 additions and 11 deletions

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@ -224,6 +224,7 @@ answer newbie questions, and generally made Django that much better:
Doug Napoleone <doug@dougma.com>
dready <wil@mojipage.com>
dusk@woofle.net
Ed Morley <https://github.com/edmorley>
eibaan@gmail.com
Emil Stenström <em@kth.se>
enlight

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@ -2,9 +2,11 @@
import pickle
import time
import warnings
from django.core.cache.backends.base import DEFAULT_TIMEOUT, BaseCache
from django.utils import six
from django.utils.deprecation import RemovedInDjango21Warning
from django.utils.encoding import force_str
from django.utils.functional import cached_property
@ -24,7 +26,7 @@ class BaseMemcachedCache(BaseCache):
self.LibraryValueNotFoundException = value_not_found_exception
self._lib = library
self._options = params.get('OPTIONS')
self._options = params.get('OPTIONS') or {}
@property
def _cache(self):
@ -32,7 +34,7 @@ class BaseMemcachedCache(BaseCache):
Implements transparent thread-safe access to a memcached client.
"""
if getattr(self, '_client', None) is None:
self._client = self._lib.Client(self._servers)
self._client = self._lib.Client(self._servers, **self._options)
return self._client
@ -163,7 +165,9 @@ class MemcachedCache(BaseMemcachedCache):
@property
def _cache(self):
if getattr(self, '_client', None) is None:
self._client = self._lib.Client(self._servers, pickleProtocol=pickle.HIGHEST_PROTOCOL)
client_kwargs = dict(pickleProtocol=pickle.HIGHEST_PROTOCOL)
client_kwargs.update(self._options)
self._client = self._lib.Client(self._servers, **client_kwargs)
return self._client
@ -175,10 +179,25 @@ class PyLibMCCache(BaseMemcachedCache):
library=pylibmc,
value_not_found_exception=pylibmc.NotFound)
# The contents of `OPTIONS` was formerly only used to set the behaviors
# attribute, but is now passed directly to the Client constructor. As such,
# any options that don't match a valid keyword argument are removed and set
# under the `behaviors` key instead, to maintain backwards compatibility.
legacy_behaviors = {}
for option in list(self._options):
if option not in ('behaviors', 'binary', 'username', 'password'):
warnings.warn(
"Specifying pylibmc cache behaviors as a top-level property "
"within `OPTIONS` is deprecated. Move `%s` into a dict named "
"`behaviors` inside `OPTIONS` instead." % option,
RemovedInDjango21Warning,
stacklevel=2,
)
legacy_behaviors[option] = self._options.pop(option)
if legacy_behaviors:
self._options.setdefault('behaviors', {}).update(legacy_behaviors)
@cached_property
def _cache(self):
client = self._lib.Client(self._servers)
if self._options:
client.behaviors = self._options
return client
return self._lib.Client(self._servers, **self._options)

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@ -27,6 +27,9 @@ details on these changes.
* ``django.utils.translation.string_concat()`` will be removed.
* ``django.core.cache.backends.memcached.PyLibMCCache`` will no longer support
passing ``pylibmc`` behavior settings as top-level attributes of ``OPTIONS``.
.. _deprecation-removed-in-2.0:
2.0

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@ -168,7 +168,10 @@ Minor features
Cache
~~~~~
* ...
* Memcached backends now pass the contents of :setting:`OPTIONS <CACHES-OPTIONS>`
as keyword arguments to the client constructors, allowing for more advanced
control of client behavior. See the :ref:`cache arguments <cache_arguments>`
documentation for examples.
CSRF
~~~~
@ -490,3 +493,7 @@ Miscellaneous
* ``django.utils.translation.string_concat()`` is deprecated in
favor of :func:`django.utils.text.format_lazy`. ``string_concat(*strings)``
can be replaced by ``format_lazy('{}' * len(strings), *strings)``.
* For the ``PyLibMCCache`` cache backend, passing ``pylibmc`` behavior settings
as top-level attributes of ``OPTIONS`` is deprecated. Set them under a
``behaviors`` key within ``OPTIONS`` instead.

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@ -403,6 +403,10 @@ behavior. These arguments are provided as additional keys in the
On some backends (``database`` in particular) this makes culling *much*
faster at the expense of more cache misses.
Memcached backends pass the contents of :setting:`OPTIONS <CACHES-OPTIONS>`
as keyword arguments to the client constructors, allowing for more advanced
control of client behavior. For example usage, see below.
* :setting:`KEY_PREFIX <CACHES-KEY_PREFIX>`: A string that will be
automatically included (prepended by default) to all cache keys
used by the Django server.
@ -437,8 +441,44 @@ of 60 seconds, and a maximum capacity of 1000 items::
}
}
Invalid arguments are silently ignored, as are invalid values of known
arguments.
Here's an example configuration for a ``python-memcached`` based backend with
an object size limit of 2MB::
CACHES = {
'default': {
'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache',
'LOCATION': '127.0.0.1:11211',
'OPTIONS': {
'server_max_value_length': 1024 * 1024 * 2,
}
}
}
Here's an example configuration for a ``pylibmc`` based backend that enables
the binary protocol, SASL authentication, and the ``ketama`` behavior mode::
CACHES = {
'default': {
'BACKEND': 'django.core.cache.backends.memcached.PyLibMCCache',
'LOCATION': '127.0.0.1:11211',
'OPTIONS': {
'binary': True,
'username': 'user',
'password': 'pass',
'behaviors': {
'ketama': True,
}
}
}
}
.. versionchanged:: 1.11
Memcached backends can now be configured using ``OPTIONS``.
In older versions, you could pass ``pylibmc`` behavior settings directly
inside ``OPTIONS``. This is deprecated in favor of setting them under a
``behaviors`` key within ``OPTIONS`` instead.
.. _the-per-site-cache:

39
tests/cache/tests.py vendored
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@ -40,6 +40,7 @@ from django.utils.cache import (
get_cache_key, learn_cache_key, patch_cache_control,
patch_response_headers, patch_vary_headers,
)
from django.utils.deprecation import RemovedInDjango21Warning
from django.utils.encoding import force_text
from django.views.decorators.cache import cache_page
@ -1241,6 +1242,14 @@ class MemcachedCacheTests(BaseMemcachedTests, TestCase):
for cache_key in settings.CACHES:
self.assertEqual(caches[cache_key]._cache.pickleProtocol, pickle.HIGHEST_PROTOCOL)
@override_settings(CACHES=caches_setting_for_tests(
base=MemcachedCache_params,
exclude=memcached_excluded_caches,
OPTIONS={'server_max_value_length': 9999},
))
def test_memcached_options(self):
self.assertEqual(cache._cache.server_max_value_length, 9999)
@unittest.skipUnless(PyLibMCCache_params, "PyLibMCCache backend not configured")
@override_settings(CACHES=caches_setting_for_tests(
@ -1259,6 +1268,36 @@ class PyLibMCCacheTests(BaseMemcachedTests, TestCase):
def test_invalid_key_characters(self):
pass
@override_settings(CACHES=caches_setting_for_tests(
base=PyLibMCCache_params,
exclude=memcached_excluded_caches,
OPTIONS={
'binary': True,
'behaviors': {'tcp_nodelay': True},
},
))
def test_pylibmc_options(self):
self.assertTrue(cache._cache.binary)
self.assertEqual(cache._cache.behaviors['tcp_nodelay'], int(True))
@override_settings(CACHES=caches_setting_for_tests(
base=PyLibMCCache_params,
exclude=memcached_excluded_caches,
OPTIONS={'tcp_nodelay': True},
))
def test_pylibmc_legacy_options(self):
deprecation_message = (
"Specifying pylibmc cache behaviors as a top-level property "
"within `OPTIONS` is deprecated. Move `tcp_nodelay` into a dict named "
"`behaviors` inside `OPTIONS` instead."
)
with warnings.catch_warnings(record=True) as warns:
warnings.simplefilter("always")
self.assertEqual(cache._cache.behaviors['tcp_nodelay'], int(True))
self.assertEqual(len(warns), 1)
self.assertIsInstance(warns[0].message, RemovedInDjango21Warning)
self.assertEqual(str(warns[0].message), deprecation_message)
@override_settings(CACHES=caches_setting_for_tests(
BACKEND='django.core.cache.backends.filebased.FileBasedCache',