Add support for multiple storage backends

* New storage drivers can be implemented in addition
  to MongoDB, for example: MySQL or Postgres, etc.
* The default database driver still MongoDB
* New storage drivers must implement the interface
  defined by the class BaseDriver
* Flexmock and hamcrest are deprected for new unit tests

Change-Id: I1cf73f28d469d2f22ecbaf345e53b9596cc0c2f6

almanach/api/main.py

@@ -22,7 +22,7 @@ from almanach.api import auth_adapter
 from almanach.api.v1 import routes
 from almanach.core import controller
 from almanach.core import opts
-from almanach.storage import database_adapter
+from almanach.storage import storage_driver
 
 LOG = log.getLogger(__name__)
 
@@ -35,10 +35,10 @@ def main():
         opts.CONF(sys.argv[1:])
         config = opts.CONF
 
-        storage = database_adapter.DatabaseAdapter(config)
-        storage.connect()
+        database_driver = storage_driver.StorageDriver(config).get_database_driver()
+        database_driver.connect()
 
-        routes.controller = controller.Controller(config, storage)
+        routes.controller = controller.Controller(config, database_driver)
         routes.auth_adapter = auth_adapter.AuthenticationAdapter(config).get_authentication_adapter()
 
         LOG.info('Listening on %s:%d', config.api.bind_ip, config.api.bind_port)

almanach/collector/main.py

@@ -20,7 +20,7 @@ from almanach.collector import bus_adapter
 from almanach.collector import retry_adapter
 from almanach.core import controller
 from almanach.core import opts
-from almanach.storage import database_adapter
+from almanach.storage import storage_driver
 
 LOG = log.getLogger(__name__)
 
@@ -30,10 +30,10 @@ def main():
         opts.CONF(sys.argv[1:])
         config = opts.CONF
 
-        storage = database_adapter.DatabaseAdapter(config)
-        storage.connect()
+        database_driver = storage_driver.StorageDriver(config).get_database_driver()
+        database_driver.connect()
 
-        application_controller = controller.Controller(config, storage)
+        application_controller = controller.Controller(config, database_driver)
         connection = kombu.Connection(hostname=config.collector.rabbit_host,
                                       port=config.collector.rabbit_port,
                                       userid=config.collector.rabbit_username,

almanach/core/exception.py

@@ -57,3 +57,7 @@ class VolumeTypeNotFoundException(AlmanachException):
             message = "Unable to find volume_type id '{volume_type_id}'".format(volume_type_id=volume_type_id)
 
         super(VolumeTypeNotFoundException, self).__init__(message)
+
+
+class DatabaseDriverNotSupportedException(AlmanachException):
+    pass

almanach/storage/drivers/base_driver.py

@@ -0,0 +1,93 @@
+# Copyright 2016 Internap.
+#
+# 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 abc
+
+
+class BaseDriver(object):
+
+    def __init__(self, config):
+        self.config = config
+
+    @abc.abstractmethod
+    def connect(self):
+        pass
+
+    @abc.abstractmethod
+    def get_active_entity(self, entity_id):
+        pass
+
+    @abc.abstractmethod
+    def count_entities(self):
+        pass
+
+    @abc.abstractmethod
+    def count_active_entities(self):
+        pass
+
+    @abc.abstractmethod
+    def count_entity_entries(self, entity_id):
+        pass
+
+    @abc.abstractmethod
+    def has_active_entity(self, entity_id):
+        pass
+
+    @abc.abstractmethod
+    def list_entities(self, project_id, start, end, entity_type=None):
+        pass
+
+    @abc.abstractmethod
+    def get_all_entities_by_id(self, entity_id):
+        pass
+
+    @abc.abstractmethod
+    def list_entities_by_id(self, entity_id, start, end):
+        pass
+
+    @abc.abstractmethod
+    def update_closed_entity(self, entity, data):
+        pass
+
+    @abc.abstractmethod
+    def insert_entity(self, entity):
+        pass
+
+    @abc.abstractmethod
+    def close_active_entity(self, entity_id, end):
+        pass
+
+    @abc.abstractmethod
+    def update_active_entity(self, entity):
+        pass
+
+    @abc.abstractmethod
+    def delete_active_entity(self, entity_id):
+        pass
+
+    @abc.abstractmethod
+    def insert_volume_type(self, volume_type):
+        pass
+
+    @abc.abstractmethod
+    def get_volume_type(self, volume_type_id):
+        pass
+
+    @abc.abstractmethod
+    def delete_volume_type(self, volume_type_id):
+        pass
+
+    @abc.abstractmethod
+    def list_volume_types(self):
+        pass

almanach/storage/drivers/mongodb_driver.py

@@ -18,14 +18,15 @@ import pymongo
 from almanach.core import exception
 from almanach.core import model
 from almanach.core.model import build_entity_from_dict
+from almanach.storage.drivers import base_driver
 
 LOG = log.getLogger(__name__)
 
 
-class DatabaseAdapter(object):
+class MongoDbDriver(base_driver.BaseDriver):
     def __init__(self, config, db=None):
+        super(MongoDbDriver, self).__init__(config)
         self.db = db
-        self.config = config
 
     def connect(self):
         connection = pymongo.MongoClient(self.config.database.connection_url, tz_aware=True)

almanach/storage/storage_driver.py

@@ -0,0 +1,32 @@
+# Copyright 2016 Internap.
+#
+# 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 oslo_log import log
+
+from almanach.core import exception
+from almanach.storage.drivers import mongodb_driver
+
+LOG = log.getLogger(__name__)
+
+
+class StorageDriver(object):
+    def __init__(self, config):
+        self.config = config
+
+    def get_database_driver(self):
+        if self.config.database.driver == 'mongodb':
+            LOG.info('Loading MongoDb storage driver')
+            return mongodb_driver.MongoDbDriver(self.config)
+        raise exception.DatabaseDriverNotSupportedException(
+                'Unknown database driver {}'.format(self.config.database.driver))

doc/source/index.rst

@@ -121,8 +121,8 @@ For example with Nova, add the topic "almanach" in the config file :code:`/etc/n
     notification_topics=almanach
 
 
-Database configuration
-----------------------
+MongoDB configuration
+---------------------
 
 Almanach requires a specific user to connect to the database.
 To create a new user, open a new MongoDB shell:

tests/core/test_controller.py

@@ -27,7 +27,7 @@ import pytz
 from almanach.core import controller
 from almanach.core import exception
 from almanach.core import model
-from almanach.storage import database_adapter
+from almanach.storage.drivers import base_driver
 
 from tests import base
 from tests.builder import a
@@ -40,7 +40,7 @@ class ControllerTest(base.BaseTestCase):
 
     def setUp(self):
         super(ControllerTest, self).setUp()
-        self.database_adapter = flexmock(database_adapter.DatabaseAdapter)
+        self.database_adapter = flexmock(base_driver.BaseDriver)
         self.controller = controller.Controller(self.config, self.database_adapter)
 
     def test_instance_created(self):

tests/storage/drivers/test_mongodb_driver.py

@@ -24,7 +24,7 @@ from hamcrest import contains_inanyorder
 
 from almanach.core import exception
 from almanach.core import model
-from almanach.storage.database_adapter import DatabaseAdapter
+from almanach.storage.drivers import mongodb_driver
 
 from tests import base
 from tests.builder import a
@@ -33,12 +33,12 @@ from tests.builder import volume
 from tests.builder import volume_type
 
 
-class DatabaseAdapterTest(base.BaseTestCase):
+class MongoDbDriverTest(base.BaseTestCase):
     def setUp(self):
-        super(DatabaseAdapterTest, self).setUp()
+        super(MongoDbDriverTest, self).setUp()
         mongo_connection = mongomock.Connection()
         self.db = mongo_connection['almanach']
-        self.adapter = DatabaseAdapter(self.config, self.db)
+        self.adapter = mongodb_driver.MongoDbDriver(self.config, self.db)
         flexmock(pymongo.MongoClient).new_instances(mongo_connection)
 
     def test_insert_instance(self):

tests/storage/test_storage_driver.py

@@ -0,0 +1,32 @@
+# Copyright 2016 Internap.
+#
+# 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 almanach.core import exception
+from almanach.storage.drivers import mongodb_driver
+from almanach.storage import storage_driver
+
+from tests import base
+
+
+class StorageDriverTest(base.BaseTestCase):
+    def setUp(self):
+        super(StorageDriverTest, self).setUp()
+        self.storage_driver = storage_driver.StorageDriver(self.config)
+
+    def test_get_default_database_adapter(self):
+        self.assertIsInstance(self.storage_driver.get_database_driver(), mongodb_driver.MongoDbDriver)
+
+    def test_get_unknown_database_adapter(self):
+        self.config_fixture.config(driver='foobar', group='database')
+        self.assertRaises(exception.DatabaseDriverNotSupportedException, self.storage_driver.get_database_driver)