Sync nova with oslo DB exception cleanup.

DB exceptions have moved to openstack/common/db/exception module so that
they can be shared with multiple DB implementations.

Deadlock checking was also added to oslo to consolidate with
DuplicateKey checking.  This allows us to clean up our
_retry_on_deadlock decorator in sqlalchemy/api.py

Fixes unrelated pep8 issue with duplicate test in test_compute also.

Change-Id: I7e985b384d1ef345e0d67c919b84b4faff869699

nova/tests/baremetal/db/test_bm_interface.py

@@ -18,7 +18,7 @@ Bare-metal DB testcase for BareMetalInterface
 """
 
 from nova import exception
-from nova.openstack.common.db.sqlalchemy import session as db_session
+from nova.openstack.common.db import exception as db_exc
 from nova.tests.baremetal.db import base
 from nova.virt.baremetal import db
 
@@ -28,7 +28,7 @@ class BareMetalInterfaceTestCase(base.BMDBTestCase):
     def test_unique_address(self):
         pif1_id = db.bm_interface_create(self.context, 1, '11:11:11:11:11:11',
                                          '0x1', 1)
-        self.assertRaises(db_session.DBError,
+        self.assertRaises(db_exc.DBError,
                           db.bm_interface_create,
                           self.context, 2, '11:11:11:11:11:11', '0x2', 2)
         # succeed after delete pif1

nova/tests/baremetal/db/test_bm_pxe_ip.py

@@ -18,7 +18,7 @@ Bare-metal DB testcase for BareMetalPxeIp
 """
 
 from nova import exception
-from nova.openstack.common.db.sqlalchemy import session as db_session
+from nova.openstack.common.db import exception as db_exc
 from nova.tests.baremetal.db import base
 from nova.tests.baremetal.db import utils
 from nova.virt.baremetal import db
@@ -51,14 +51,14 @@ class BareMetalPxeIpTestCase(base.BMDBTestCase):
         # address duplicates
         i = utils.new_bm_pxe_ip(address='10.1.1.1',
                                 server_address='10.1.1.201')
-        self.assertRaises(db_session.DBError,
+        self.assertRaises(db_exc.DBError,
                           db.bm_pxe_ip_create_direct,
                           self.context, i)
 
         # server_address duplicates
         i = utils.new_bm_pxe_ip(address='10.1.1.3',
                                 server_address='10.1.1.101')
-        self.assertRaises(db_session.DBError,
+        self.assertRaises(db_exc.DBError,
                           db.bm_pxe_ip_create_direct,
                           self.context, i)
 

nova/tests/baremetal/test_pxe.py

@@ -27,7 +27,7 @@ from oslo.config import cfg
 from testtools import matchers
 
 from nova import exception
-from nova.openstack.common.db.sqlalchemy import session as db_session
+from nova.openstack.common.db import exception as db_exc
 from nova.tests.baremetal.db import base as bm_db_base
 from nova.tests.baremetal.db import utils as bm_db_utils
 from nova.tests.image import fake as fake_image
@@ -529,7 +529,7 @@ class PXEPublicMethodsTestCase(BareMetalPXETestCase):
                 AndRaise(exception.NovaException)
         bm_utils.unlink_without_raise(pxe_path)
         self.driver._collect_mac_addresses(self.context, self.node).\
-                AndRaise(db_session.DBError)
+                AndRaise(db_exc.DBError)
         bm_utils.rmtree_without_raise(
                 os.path.join(CONF.baremetal.tftp_root, 'fake-uuid'))
         self.mox.ReplayAll()

nova/virt/baremetal/db/sqlalchemy/api.py

@@ -28,6 +28,7 @@ from sqlalchemy.sql.expression import literal_column
 import nova.context
 from nova.db.sqlalchemy import api as sqlalchemy_api
 from nova import exception
+from nova.openstack.common.db import exception as db_exc
 from nova.openstack.common import log as logging
 from nova.openstack.common import timeutils
 from nova.openstack.common import uuidutils
@@ -399,7 +400,7 @@ def bm_interface_set_vif_uuid(context, if_id, vif_uuid):
         try:
             session.add(bm_interface)
             session.flush()
-        except db_session.DBError, e:
+        except db_exc.DBError, e:
             # TODO(deva): clean up when db layer raises DuplicateKeyError
             if str(e).find('IntegrityError') != -1:
                 raise exception.NovaException(_("Baremetal interface %s "

nova/virt/baremetal/db/sqlalchemy/session.py

@@ -44,8 +44,6 @@ CONF.import_opt('sqlite_db', 'nova.openstack.common.db.sqlalchemy.session')
 _ENGINE = None
 _MAKER = None
 
-DBError = nova_session.DBError
-
 
 def get_session(autocommit=True, expire_on_commit=False):
     """Return a SQLAlchemy session."""

nova/virt/baremetal/pxe.py

@@ -27,7 +27,7 @@ from oslo.config import cfg
 
 from nova.compute import instance_types
 from nova import exception
-from nova.openstack.common.db.sqlalchemy import session as db_session
+from nova.openstack.common.db import exception as db_exc
 from nova.openstack.common import fileutils
 from nova.openstack.common import log as logging
 from nova.openstack.common import timeutils
@@ -428,7 +428,7 @@ class PXE(base.NodeDriver):
         bm_utils.unlink_without_raise(get_pxe_config_file_path(instance))
         try:
             macs = self._collect_mac_addresses(context, node)
-        except db_session.DBError:
+        except db_exc.DBError:
             pass
         else:
             for mac in macs: