Made get_capabilities a classmethod instead of object method

Capabilities are the same for all objects so there is no need for them
to be nonstatic. Another benefit is that we can check capabilities of
the Connection without the need to create an object and open real
connection.

Change-Id: Ie9314cb49b4c2bffb2bae4d5eeca6f5d8e2637ce

ceilometer/storage/base.py

@@ -27,7 +27,6 @@ from six import moves
 
 from ceilometer.openstack.common.gettextutils import _  # noqa
 from ceilometer.openstack.common import timeutils
-from ceilometer import utils
 
 
 def iter_period(start, end, period):
@@ -121,7 +120,7 @@ class Connection(object):
 
     """A dictionary representing the capabilities of this driver.
     """
-    DEFAULT_CAPABILITIES = {
+    CAPABILITIES = {
         'meters': {'pagination': False,
                    'query': {'simple': False,
                              'metadata': False,
@@ -157,10 +156,9 @@ class Connection(object):
         'events': {'query': {'simple': False}},
     }
 
-    def __init__(self, conf, AVAILABLE_CAPABILITIES):
+    def __init__(self, conf):
         """Constructor."""
-        self._CAPABILITIES = utils.update_nested(self.DEFAULT_CAPABILITIES,
+        pass
-                                                 AVAILABLE_CAPABILITIES)
 
     @staticmethod
     def upgrade():
@@ -397,7 +395,8 @@ class Connection(object):
         raise NotImplementedError('Complex query for alarms '
                                   'history is not implemented.')
 
-    def get_capabilities(self):
+    @classmethod
+    def get_capabilities(cls):
         """Return an dictionary representing the capabilities of each driver.
         """
-        return self._CAPABILITIES
+        return cls.CAPABILITIES

ceilometer/storage/impl_db2.py

@@ -38,6 +38,7 @@ from ceilometer import storage
 from ceilometer.storage import base
 from ceilometer.storage import models
 from ceilometer.storage import pymongo_base
+from ceilometer import utils
 
 LOG = log.getLogger(__name__)
 
@@ -88,6 +89,8 @@ class Connection(pymongo_base.Connection):
     """DB2 connection.
     """
 
+    CAPABILITIES = utils.update_nested(pymongo_base.Connection.CAPABILITIES,
+                                       AVAILABLE_CAPABILITIES)
     CONNECTION_POOL = pymongo_base.ConnectionPool()
 
     GROUP = {'_id': '$counter_name',
@@ -112,7 +115,6 @@ class Connection(pymongo_base.Connection):
     SECONDS_IN_A_DAY = 86400
 
     def __init__(self, conf):
-        super(Connection, self).__init__(conf, AVAILABLE_CAPABILITIES)
         url = conf.database.connection
 
         # Since we are using pymongo, even though we are connecting to DB2

ceilometer/storage/impl_hbase.py

@@ -110,6 +110,8 @@ AVAILABLE_CAPABILITIES = {
 class Connection(base.Connection):
     """HBase connection.
     """
+    CAPABILITIES = utils.update_nested(base.Connection.CAPABILITIES,
+                                       AVAILABLE_CAPABILITIES)
 
     _memory_instance = None
 
@@ -122,7 +124,6 @@ class Connection(base.Connection):
 
     def __init__(self, conf):
         """Hbase Connection Initialization."""
-        super(Connection, self).__init__(conf, AVAILABLE_CAPABILITIES)
         opts = self._parse_connection_url(conf.database.connection)
 
         if opts['host'] == '__test__':

ceilometer/storage/impl_log.py

@@ -39,9 +39,6 @@ class Connection(base.Connection):
     """Base class for storage system connections.
     """
 
-    def __init__(self, conf):
-        super(Connection, self).__init__(conf, {})
-
     def upgrade(self):
         pass
 

ceilometer/storage/impl_mongodb.py

@@ -42,6 +42,7 @@ from ceilometer import storage
 from ceilometer.storage import base
 from ceilometer.storage import models
 from ceilometer.storage import pymongo_base
+from ceilometer import utils
 
 cfg.CONF.import_opt('time_to_live', 'ceilometer.storage',
                     group="database")
@@ -101,6 +102,8 @@ AVAILABLE_CAPABILITIES = {
 class Connection(pymongo_base.Connection):
     """MongoDB connection.
     """
+    CAPABILITIES = utils.update_nested(pymongo_base.Connection.CAPABILITIES,
+                                       AVAILABLE_CAPABILITIES)
 
     CONNECTION_POOL = pymongo_base.ConnectionPool()
 
@@ -407,7 +410,6 @@ class Connection(pymongo_base.Connection):
                                     hour=23, minute=59, second=59)
 
     def __init__(self, conf):
-        super(Connection, self).__init__(conf, AVAILABLE_CAPABILITIES)
         url = conf.database.connection
 
         # NOTE(jd) Use our own connection pooling on top of the Pymongo one.

ceilometer/storage/impl_sqlalchemy.py

@@ -239,9 +239,10 @@ def make_query_from_filter(session, query, sample_filter, require_meter=True):
 
 class Connection(base.Connection):
     """SqlAlchemy connection."""
+    CAPABILITIES = utils.update_nested(base.Connection.CAPABILITIES,
+                                       AVAILABLE_CAPABILITIES)
 
     def __init__(self, conf):
-        super(Connection, self).__init__(conf, AVAILABLE_CAPABILITIES)
         self._engine_facade = sqlalchemy_session.EngineFacade.from_config(
             conf.database.connection, cfg.CONF)
 

ceilometer/storage/pymongo_base.py

@@ -143,12 +143,8 @@ COMMON_AVAILABLE_CAPABILITIES = {
 class Connection(base.Connection):
     """Base Connection class for MongoDB and DB2 drivers.
     """
-
+    CAPABILITIES = utils.update_nested(base.Connection.CAPABILITIES,
-    def __init__(self, conf, AVAILABLE_CAPABILITIES):
+                                       COMMON_AVAILABLE_CAPABILITIES)
-        super(Connection, self).__init__(
-            conf,
-            utils.update_nested(COMMON_AVAILABLE_CAPABILITIES,
-                                AVAILABLE_CAPABILITIES))
 
     def get_users(self, source=None):
         """Return an iterable of user id strings.

ceilometer/tests/storage/test_impl_db2.py

@@ -24,14 +24,11 @@
 
 """
 
-from ceilometer.tests import db as tests_db
+from ceilometer.storage import impl_db2
+from ceilometer.tests import base as test_base
 
 
-class DB2EngineTestBase(tests_db.TestBase):
+class CapabilitiesTest(test_base.BaseTestCase):
-    db_manager = tests_db.DB2Manager()
-
-
-class CapabilitiesTest(DB2EngineTestBase):
     # Check the returned capabilities list, which is specific to each DB
     # driver
 
@@ -72,5 +69,5 @@ class CapabilitiesTest(DB2EngineTestBase):
             'events': {'query': {'simple': False}}
         }
 
-        actual_capabilities = self.conn.get_capabilities()
+        actual_capabilities = impl_db2.Connection.get_capabilities()
         self.assertEqual(expected_capabilities, actual_capabilities)

ceilometer/tests/storage/test_impl_hbase.py

@@ -27,6 +27,7 @@
 from mock import patch
 
 from ceilometer.storage import impl_hbase as hbase
+from ceilometer.tests import base as test_base
 from ceilometer.tests import db as tests_db
 
 
@@ -58,7 +59,7 @@ class ConnectionTest(HBaseEngineTestBase):
         self.assertIsInstance(conn.conn_pool, TestConn)
 
 
-class CapabilitiesTest(HBaseEngineTestBase):
+class CapabilitiesTest(test_base.BaseTestCase):
     # Check the returned capabilities list, which is specific to each DB
     # driver
 
@@ -99,5 +100,5 @@ class CapabilitiesTest(HBaseEngineTestBase):
             'events': {'query': {'simple': False}}
         }
 
-        actual_capabilities = self.conn.get_capabilities()
+        actual_capabilities = hbase.Connection.get_capabilities()
         self.assertEqual(expected_capabilities, actual_capabilities)

ceilometer/tests/storage/test_impl_mongodb.py

@@ -26,6 +26,7 @@
 
 from ceilometer.storage import base
 from ceilometer.storage import impl_mongodb
+from ceilometer.tests import base as test_base
 from ceilometer.tests import db as tests_db
 from ceilometer.tests.storage import test_storage_scenarios
 
@@ -145,7 +146,7 @@ class AlarmTestPagination(test_storage_scenarios.AlarmTestBase,
             self.assertTrue(True)
 
 
-class CapabilitiesTest(MongoDBEngineTestBase):
+class CapabilitiesTest(test_base.BaseTestCase):
     # Check the returned capabilities list, which is specific to each DB
     # driver
 
@@ -186,5 +187,5 @@ class CapabilitiesTest(MongoDBEngineTestBase):
             'events': {'query': {'simple': False}}
         }
 
-        actual_capabilities = self.conn.get_capabilities()
+        actual_capabilities = impl_mongodb.Connection.get_capabilities()
         self.assertEqual(expected_capabilities, actual_capabilities)

ceilometer/tests/storage/test_impl_sqlalchemy.py

@@ -29,8 +29,11 @@ import repr
 from mock import patch
 
 from ceilometer.openstack.common import timeutils
+from ceilometer.storage import impl_sqlalchemy
 from ceilometer.storage import models
 from ceilometer.storage.sqlalchemy import models as sql_models
+
+from ceilometer.tests import base as test_base
 from ceilometer.tests import db as tests_db
 from ceilometer.tests.storage import test_storage_scenarios as scenarios
 
@@ -214,7 +217,7 @@ class RelationshipTest(scenarios.DBTestBase):
                     )).count())
 
 
-class CapabilitiesTest(EventTestBase):
+class CapabilitiesTest(test_base.BaseTestCase):
     # Check the returned capabilities list, which is specific to each DB
     # driver
 
@@ -255,5 +258,5 @@ class CapabilitiesTest(EventTestBase):
             'events': {'query': {'simple': True}}
         }
 
-        actual_capabilities = self.conn.get_capabilities()
+        actual_capabilities = impl_sqlalchemy.Connection.get_capabilities()
         self.assertEqual(expected_capabilities, actual_capabilities)