Use new enginefacade for quota and provisioning blocks

Use reader and writer for db operations.

Partially-Implements blueprint: enginefacade-switch

Change-Id: I3adaec4cae814c1feb88aa646b99823de9c0eb9e

neutron/api/v2/base.py

@@ -486,7 +486,7 @@ class Controller(object):
         def notify(create_result):
             # Ensure usage trackers for all resources affected by this API
             # operation are marked as dirty
-            with request.context.session.begin():
+            with db_api.context_manager.writer.using(request.context):
                 # Commit the reservation(s)
                 for reservation in reservations:
                     quota.QUOTAS.commit_reservation(

neutron/db/quota/api.py

@@ -85,7 +85,7 @@ def set_quota_usage(context, resource, tenant_id,
     :param delta: Specifies whether in_use is an absolute number
                   or a delta (default to False)
     """
-    with db_api.autonested_transaction(context.session):
+    with db_api.context_manager.writer.using(context):
         usage_data = quota_obj.QuotaUsage.get_object(
             context, resource=resource, project_id=tenant_id)
         if not usage_data:

neutron/db/quota/driver.py

@@ -168,7 +168,7 @@ class DbQuotaDriver(object):
         # locks should be ok to use when support for sending "hotspot" writes
         # to a single node will be available.
         requested_resources = deltas.keys()
-        with db_api.autonested_transaction(context.session):
+        with db_api.context_manager.writer.using(context):
             # get_tenant_quotes needs in input a dictionary mapping resource
             # name to BaseResosurce instances so that the default quota can be
             # retrieved

neutron/pecan_wsgi/hooks/quota_enforcement.py

@@ -19,6 +19,7 @@ from oslo_log import log as logging
 from pecan import hooks
 
 from neutron.common import exceptions
+from neutron.db import api as db_api
 from neutron import manager
 from neutron import quota
 from neutron.quota import resource_registry
@@ -66,7 +67,7 @@ class QuotaEnforcementHook(hooks.PecanHook):
         if not reservations:
             return
         neutron_context = state.request.context.get('neutron_context')
-        with neutron_context.session.begin():
+        with db_api.context_manager.writer.using(neutron_context):
             # Commit the reservation(s)
             for reservation in reservations:
                 quota.QUOTAS.commit_reservation(

neutron/quota/resource.py

@@ -177,7 +177,7 @@ class TrackedResource(BaseResource):
     def mark_dirty(self, context):
         if not self._dirty_tenants:
             return
-        with db_api.autonested_transaction(context.session):
+        with db_api.context_manager.writer.using(context):
             # It is not necessary to protect this operation with a lock.
             # Indeed when this method is called the request has been processed
             # and therefore all resources created or deleted.

neutron/quota/resource_registry.py

@@ -15,6 +15,7 @@ from oslo_log import log
 import six
 
 from neutron._i18n import _, _LI, _LW
+from neutron.db import api as db_api
 from neutron.quota import resource
 
 LOG = log.getLogger(__name__)
@@ -71,7 +72,7 @@ def set_resources_dirty(context):
         return
 
     for res in get_all_resources().values():
-        with context.session.begin(subtransactions=True):
+        with db_api.context_manager.writer.using(context):
             if is_tracked(res.name) and res.dirty:
                 res.mark_dirty(context)
 

neutron/tests/unit/db/test_provisioning_blocks.py

@@ -18,6 +18,7 @@ import testtools
 
 from neutron.callbacks import registry
 from neutron.callbacks import resources
+from neutron.db import api as db_api
 from neutron.db import models_v2
 from neutron.db import provisioning_blocks as pb
 from neutron.tests.unit import testlib_api
@@ -37,7 +38,7 @@ class TestStatusBarriers(testlib_api.SqlTestCase):
                            pb.PROVISIONING_COMPLETE)
 
     def _make_net(self):
-        with self.ctx.session.begin():
+        with db_api.context_manager.writer.using(self.ctx):
             net = models_v2.Network(name='net_net', status='ACTIVE',
                                     tenant_id='1', admin_state_up=True)
             self.ctx.session.add(net)
@@ -45,7 +46,7 @@ class TestStatusBarriers(testlib_api.SqlTestCase):
 
     def _make_port(self):
         net = self._make_net()
-        with self.ctx.session.begin():
+        with db_api.context_manager.writer.using(self.ctx):
             port = models_v2.Port(network_id=net.id, mac_address='1',
                                   tenant_id='1', admin_state_up=True,
                                   status='DOWN', device_id='2',