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.

1 files changed, 27 insertions, 8 deletions

diff --git a/django/core/cache/backends/memcached.py b/django/core/cache/backends/memcached.py
index ee6b3b7712..2ca9f663d7 100644
--- a/django/core/cache/backends/memcached.py
+++ b/django/core/cache/backends/memcached.py
@@ -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)