Add noop cache support to Pool Manager

Add a noop cache to Pool Manager. This always raises
a PoolManagerStatusNotFound exception on retrieve.

Partial-Bug: 1413346
Change-Id: I163fb12061325af403b9a808f5b49d90a744e50e

designate/pool_manager/cache/impl_noop/__init__.py

@@ -0,0 +1,36 @@
+# Copyright 2014 eBay Inc.
+#
+# Author: Ron Rickard <rrickard@ebaysf.com>
+#
+# 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.
+from designate import exceptions
+from designate.pool_manager.cache import base as cache_base
+
+
+class NoopPoolManagerCache(cache_base.PoolManagerCache):
+    __plugin_name__ = 'noop'
+
+    def __init__(self):
+        super(NoopPoolManagerCache, self).__init__()
+
+    def get_name(self):
+        return self.name
+
+    def clear(self, context, pool_manager_status):
+        pass
+
+    def store(self, context, pool_manager_status):
+        pass
+
+    def retrieve(self, context, server_id, domain_id, action):
+        raise exceptions.PoolManagerStatusNotFound

designate/tests/test_pool_manager/cache/test_noop.py

@@ -0,0 +1,37 @@
+# Copyright 2014 eBay Inc.
+#
+# Author: Ron Rickard <rrickard@ebaysf.com>
+#
+# 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.
+import testtools
+
+from designate import exceptions
+from designate.pool_manager import cache
+from designate.tests import TestCase
+from designate.tests.test_pool_manager.cache import PoolManagerCacheTestCase
+
+
+class NoopPoolManagerCacheTest(PoolManagerCacheTestCase, TestCase):
+    def setUp(self):
+        super(NoopPoolManagerCacheTest, self).setUp()
+
+        self.cache = cache.get_pool_manager_cache('noop')
+
+    def test_store_and_retrieve(self):
+        expected = self.create_pool_manager_status()
+        self.cache.store(self.admin_context, expected)
+
+        with testtools.ExpectedException(exceptions.PoolManagerStatusNotFound):
+            self.cache.retrieve(
+                self.admin_context, expected.server_id, expected.domain_id,
+                expected.action)

setup.cfg

@@ -62,6 +62,7 @@ designate.storage =
 
 designate.pool_manager.cache =
     memcache = designate.pool_manager.cache.impl_memcache:MemcachePoolManagerCache
+    noop = designate.pool_manager.cache.impl_noop:NoopPoolManagerCache
     sqlalchemy = designate.pool_manager.cache.impl_sqlalchemy:SQLAlchemyPoolManagerCache
 
 designate.notification.handler =