Merge "Make CacheIsolatingProxy public"

oslo_cache/testing.py

@@ -0,0 +1,70 @@
+# Copyright 2013 Metacloud
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""Items useful for external testing."""
+
+
+import copy
+
+from dogpile.cache import proxy
+
+from oslo_cache import core as cache
+
+
+__all__ = [
+    'CacheIsolatingProxy',
+]
+
+
+NO_VALUE = cache.NO_VALUE
+
+
+def _copy_value(value):
+    if value is not NO_VALUE:
+        value = copy.deepcopy(value)
+    return value
+
+
+# NOTE(morganfainberg): WARNING - It is not recommended to use the Memory
+# backend for dogpile.cache in a real deployment under any circumstances. The
+# backend does no cleanup of expired values and therefore will leak memory. The
+# backend is not implemented in a way to share data across processes (e.g.
+# Keystone in HTTPD.  This proxy is a hack to get around the lack of isolation
+# of values in memory.  Currently it blindly stores and retrieves the values
+# from the cache, and modifications to dicts/lists/etc returned can result in
+# changes to the cached values.  In short, do not use the dogpile.cache.memory
+# backend unless you are running tests or expecting odd/strange results.
+class CacheIsolatingProxy(proxy.ProxyBackend):
+    """Proxy that forces a memory copy of stored values.
+
+    The default in-memory cache-region does not perform a copy on values it
+    is meant to cache.  Therefore if the value is modified after set or after
+    get, the cached value also is modified.  This proxy does a copy as the last
+    thing before storing data.
+
+    In your application's tests, you'll want to set this as a proxy for the
+    in-memory cache, like this::
+
+        self.config_fixture.config(
+            group='cache',
+            backend='dogpile.cache.memory',
+            enabled=True,
+            proxies=['oslo_cache.testing.CacheIsolatingProxy'])
+
+    """
+    def get(self, key):
+        return _copy_value(self.proxied.get(key))
+
+    def set(self, key, value):
+        self.proxied.set(key, _copy_value(value))

oslo_cache/tests/test_cache.py

@@ -20,11 +20,11 @@ import uuid
 from dogpile.cache import proxy
 import mock
 from oslo_config import cfg
+from oslo_config import fixture as config_fixture
 from oslotest import base
 
 from oslo_cache import core as cache
 from oslo_cache import exception
-from oslo_config import fixture as config_fixture
 
 
 NO_VALUE = cache.NO_VALUE
@@ -42,7 +42,7 @@ class BaseTestCase(base.BaseTestCase):
             group='cache',
             backend='dogpile.cache.memory',
             enabled=True,
-            proxies=['oslo_cache.tests.test_cache.CacheIsolatingProxy'])
+            proxies=['oslo_cache.testing.CacheIsolatingProxy'])
 
 
 def _copy_value(value):
@@ -51,29 +51,6 @@ def _copy_value(value):
     return value
 
 
-# NOTE(morganfainberg): WARNING - It is not recommended to use the Memory
-# backend for dogpile.cache in a real deployment under any circumstances. The
-# backend does no cleanup of expired values and therefore will leak memory. The
-# backend is not implemented in a way to share data across processes (e.g.
-# Keystone in HTTPD.  This proxy is a hack to get around the lack of isolation
-# of values in memory.  Currently it blindly stores and retrieves the values
-# from the cache, and modifications to dicts/lists/etc returned can result in
-# changes to the cached values.  In short, do not use the dogpile.cache.memory
-# backend unless you are running tests or expecting odd/strange results.
-class CacheIsolatingProxy(proxy.ProxyBackend):
-    """Proxy that forces a memory copy of stored values.
-    The default in-memory cache-region does not perform a copy on values it
-    is meant to cache.  Therefore if the value is modified after set or after
-    get, the cached value also is modified.  This proxy does a copy as the last
-    thing before storing data.
-    """
-    def get(self, key):
-        return _copy_value(self.proxied.get(key))
-
-    def set(self, key, value):
-        self.proxied.set(key, _copy_value(value))
-
-
 class TestProxy(proxy.ProxyBackend):
     def get(self, key):
         value = _copy_value(self.proxied.get(key))