Move db access out into a seperate file.

This is in preparation for using the openstack.common Service classes.

Change-Id: I5ac78202199217387b91685e9d0409ae08cc18e0

ceilometer/central/manager.py

@@ -19,6 +19,7 @@
 from nova import manager
 
 from ceilometer import extension_manager
+from ceilometer.compute import resources
 from ceilometer.openstack.common import cfg
 from ceilometer.openstack.common import log
 from ceilometer import publish
@@ -38,6 +39,9 @@ PLUGIN_NAMESPACE = 'ceilometer.poll.central'
 
 
 class AgentManager(manager.Manager):
+    def __init__(self, host=None):
+        super(AgentManager, self).__init__(host=host)
+        self.resources = resources.Resources()
 
     def init_host(self):
         self.ext_manager = extension_manager.ActivatedExtensionManager(

ceilometer/compute/manager.py

@@ -21,6 +21,7 @@ from nova import manager
 from ceilometer import extension_manager
 from ceilometer.openstack.common import cfg
 from ceilometer.openstack.common import log
+from ceilometer.compute import resources
 from ceilometer import publish
 
 OPTS = [
@@ -40,6 +41,10 @@ PLUGIN_NAMESPACE = 'ceilometer.poll.compute'
 
 class AgentManager(manager.Manager):
 
+    def __init__(self, host=None):
+        super(AgentManager, self).__init__(host=host)
+        self.resources = resources.Resources()
+
     def init_host(self):
         self.ext_manager = extension_manager.ActivatedExtensionManager(
             namespace=PLUGIN_NAMESPACE,
@@ -75,8 +80,6 @@ class AgentManager(manager.Manager):
 
     def periodic_tasks(self, context, raise_on_error=False):
         """Tasks to be run at a periodic interval."""
-        # FIXME(dhellmann): How do we get a list of instances without
-        # talking directly to the database?
-        for instance in self.db.instance_get_all_by_host(context, self.host):
+        for instance in self.resources.instance_get_all_by_host(context):
             if instance['vm_state'] != 'error':
                 self.poll_instance(context, instance)

ceilometer/compute/resources.py

@@ -0,0 +1,37 @@
+#
+# 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 ceilometer.openstack.common import cfg
+from nova.openstack.common import importutils
+
+
+db_driver_opt = cfg.StrOpt('db_driver',
+                           default='nova.db',
+                           help='driver to use for database access')
+
+
+cfg.CONF.register_opt(db_driver_opt)
+
+
+# FIXME(dhellmann): How do we get a list of instances without
+# talking directly to the database?
+class Resources(object):
+
+    def __init__(self):
+        self.db = importutils.import_module(cfg.CONF.db_driver)
+
+    def instance_get_all_by_host(self, context):
+        return self.db.instance_get_all_by_host(context, cfg.CONF.host)
+
+    def floating_ip_get_all(self, context):
+        return self.db.floating_ip_get_all(context)

ceilometer/network/floatingip.py

@@ -31,7 +31,7 @@ class FloatingIPPollster(plugin.CentralPollster):
 
     def get_counters(self, manager, context):
         try:
-            ips = manager.db.floating_ip_get_all(context)
+            ips = manager.resources.floating_ip_get_all(context)
         except exception.FloatingIpNotFoundForHost:
             pass
         else:

tests/compute/test_manager.py

@@ -84,10 +84,10 @@ class TestRunTasks(base.TestCase):
         stillborn_instance = mock.MagicMock()
         stillborn_instance.name = 'stillborn'
         stillborn_instance.vm_state = 'error'
-        self.mox.StubOutWithMock(self.mgr.db, 'instance_get_all_by_host')
-        self.mgr.db.instance_get_all_by_host(
-            None,
-            self.mgr.host,
+        self.mox.StubOutWithMock(self.mgr.resources,
+                                 'instance_get_all_by_host')
+        self.mgr.resources.instance_get_all_by_host(
+            None
             ).AndReturn([self.instance, stillborn_instance])
 
         self.mox.ReplayAll()