Enable N302: Import modules only

Fix all N302 issues, and re-enable.

Change-Id: Ic94d144c915b228b7ff2fd9c5951875e159ffcdd

10 files changed, 71 insertions, 56 deletions

diff --git a/nova/virt/baremetal/__init__.py b/nova/virt/baremetal/__init__.py
index e3ecef8215..9c8318660f 100644
--- a/nova/virt/baremetal/__init__.py
+++ b/nova/virt/baremetal/__init__.py
@@ -12,4 +12,6 @@
 #    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 nova.virt.baremetal.driver import BareMetalDriver
+from nova.virt.baremetal import driver
+
+BareMetalDriver = driver.BareMetalDriver
diff --git a/nova/virt/baremetal/db/sqlalchemy/api.py b/nova/virt/baremetal/db/sqlalchemy/api.py
index e2240053c5..34bcd12290 100644
--- a/nova/virt/baremetal/db/sqlalchemy/api.py
+++ b/nova/virt/baremetal/db/sqlalchemy/api.py
@@ -23,14 +23,13 @@
 from sqlalchemy.sql.expression import asc
 from sqlalchemy.sql.expression import literal_column
 
-from nova.db.sqlalchemy.api import is_user_context
-from nova.db.sqlalchemy.api import require_admin_context
+from nova.db.sqlalchemy import api as sqlalchemy_api
 from nova import exception
 from nova.openstack.common import log as logging
 from nova.openstack.common import timeutils
 from nova.openstack.common import uuidutils
 from nova.virt.baremetal.db.sqlalchemy import models
-from nova.virt.baremetal.db.sqlalchemy.session import get_session
+from nova.virt.baremetal.db.sqlalchemy import session as db_session
 
 LOG = logging.getLogger(__name__)
 
@@ -44,7 +43,7 @@ def model_query(context, *args, **kwargs):
     :param project_only: if present and context is user-type, then restrict
             query to match the context's project_id.
     """
-    session = kwargs.get('session') or get_session()
+    session = kwargs.get('session') or db_session.get_session()
     read_deleted = kwargs.get('read_deleted') or context.read_deleted
     project_only = kwargs.get('project_only')
 
@@ -60,7 +59,7 @@ def model_query(context, *args, **kwargs):
         raise Exception(
                 _("Unrecognized read_deleted value '%s'") % read_deleted)
 
-    if project_only and is_user_context(context):
+    if project_only and sqlalchemy_api.is_user_context(context):
         query = query.filter_by(project_id=context.project_id)
 
     return query
@@ -68,7 +67,7 @@ def model_query(context, *args, **kwargs):
 
 def _save(ref, session=None):
     if not session:
-        session = get_session()
+        session = db_session.get_session()
     # We must not call ref.save() with session=None, otherwise NovaBase
     # uses nova-db's session, which cannot access bm-db.
     ref.save(session=session)
@@ -81,7 +80,7 @@ def _build_node_order_by(query):
     return query
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_node_get_all(context, service_host=None):
     query = model_query(context, models.BareMetalNode, read_deleted="no")
     if service_host:
@@ -89,7 +88,7 @@ def bm_node_get_all(context, service_host=None):
     return query.all()
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_node_find_free(context, service_host=None,
                       cpus=None, memory_mb=None, local_gb=None):
     query = model_query(context, models.BareMetalNode, read_deleted="no")
@@ -106,7 +105,7 @@ def bm_node_find_free(context, service_host=None,
     return query.first()
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_node_get(context, bm_node_id):
     # bm_node_id may be passed as a string. Convert to INT to improve DB perf.
     bm_node_id = int(bm_node_id)
@@ -120,7 +119,7 @@ def bm_node_get(context, bm_node_id):
     return result
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_node_get_by_instance_uuid(context, instance_uuid):
     if not uuidutils.is_uuid_like(instance_uuid):
         raise exception.InstanceNotFound(instance_id=instance_uuid)
@@ -135,7 +134,7 @@ def bm_node_get_by_instance_uuid(context, instance_uuid):
     return result
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_node_create(context, values):
     bm_node_ref = models.BareMetalNode()
     bm_node_ref.update(values)
@@ -143,14 +142,14 @@ def bm_node_create(context, values):
     return bm_node_ref
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_node_update(context, bm_node_id, values):
     model_query(context, models.BareMetalNode, read_deleted="no").\
             filter_by(id=bm_node_id).\
             update(values)
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_node_set_uuid_safe(context, bm_node_id, values):
     """Associate an instance to a node safely
 
@@ -164,7 +163,7 @@ def bm_node_set_uuid_safe(context, bm_node_id, values):
         raise exception.NovaException(_(
             "instance_uuid must be supplied to bm_node_set_uuid_safe"))
 
-    session = get_session()
+    session = db_session.get_session()
     with session.begin():
         query = model_query(context, models.BareMetalNode,
                                 session=session, read_deleted="no").\
@@ -181,7 +180,7 @@ def bm_node_set_uuid_safe(context, bm_node_id, values):
     return ref
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_node_destroy(context, bm_node_id):
     model_query(context, models.BareMetalNode).\
             filter_by(id=bm_node_id).\
@@ -190,13 +189,13 @@ def bm_node_destroy(context, bm_node_id):
                     'updated_at': literal_column('updated_at')})
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_pxe_ip_get_all(context):
     query = model_query(context, models.BareMetalPxeIp, read_deleted="no")
     return query.all()
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_pxe_ip_create(context, address, server_address):
     ref = models.BareMetalPxeIp()
     ref.address = address
@@ -205,7 +204,7 @@ def bm_pxe_ip_create(context, address, server_address):
     return ref
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_pxe_ip_create_direct(context, bm_pxe_ip):
     ref = bm_pxe_ip_create(context,
                            address=bm_pxe_ip['address'],
@@ -213,7 +212,7 @@ def bm_pxe_ip_create_direct(context, bm_pxe_ip):
     return ref
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_pxe_ip_destroy(context, ip_id):
     # Delete physically since it has unique columns
     model_query(context, models.BareMetalPxeIp, read_deleted="no").\
@@ -221,7 +220,7 @@ def bm_pxe_ip_destroy(context, ip_id):
             delete()
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_pxe_ip_destroy_by_address(context, address):
     # Delete physically since it has unique columns
     model_query(context, models.BareMetalPxeIp, read_deleted="no").\
@@ -229,7 +228,7 @@ def bm_pxe_ip_destroy_by_address(context, address):
             delete()
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_pxe_ip_get(context, ip_id):
     result = model_query(context, models.BareMetalPxeIp, read_deleted="no").\
             filter_by(id=ip_id).\
@@ -238,7 +237,7 @@ def bm_pxe_ip_get(context, ip_id):
     return result
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_pxe_ip_get_by_bm_node_id(context, bm_node_id):
     result = model_query(context, models.BareMetalPxeIp, read_deleted="no").\
             filter_by(bm_node_id=bm_node_id).\
@@ -250,9 +249,9 @@ def bm_pxe_ip_get_by_bm_node_id(context, bm_node_id):
     return result
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_pxe_ip_associate(context, bm_node_id):
-    session = get_session()
+    session = db_session.get_session()
     with session.begin():
         # Check if the node really exists
         node_ref = model_query(context, models.BareMetalNode,
@@ -288,14 +287,14 @@ def bm_pxe_ip_associate(context, bm_node_id):
         return ip_ref.id
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_pxe_ip_disassociate(context, bm_node_id):
     model_query(context, models.BareMetalPxeIp, read_deleted="no").\
             filter_by(bm_node_id=bm_node_id).\
             update({'bm_node_id': None})
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_interface_get(context, if_id):
     result = model_query(context, models.BareMetalInterface,
                          read_deleted="no").\
@@ -309,14 +308,14 @@ def bm_interface_get(context, if_id):
     return result
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_interface_get_all(context):
     query = model_query(context, models.BareMetalInterface,
                         read_deleted="no")
     return query.all()
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_interface_destroy(context, if_id):
     # Delete physically since it has unique columns
     model_query(context, models.BareMetalInterface, read_deleted="no").\
@@ -324,7 +323,7 @@ def bm_interface_destroy(context, if_id):
             delete()
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_interface_create(context, bm_node_id, address, datapath_id, port_no):
     ref = models.BareMetalInterface()
     ref.bm_node_id = bm_node_id
@@ -335,9 +334,9 @@ def bm_interface_create(context, bm_node_id, address, datapath_id, port_no):
     return ref.id
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_interface_set_vif_uuid(context, if_id, vif_uuid):
-    session = get_session()
+    session = db_session.get_session()
     with session.begin():
         bm_interface = model_query(context, models.BareMetalInterface,
                                 read_deleted="no", session=session).\
@@ -361,7 +360,7 @@ def bm_interface_set_vif_uuid(context, if_id, vif_uuid):
                 raise e
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_interface_get_by_vif_uuid(context, vif_uuid):
     result = model_query(context, models.BareMetalInterface,
                          read_deleted="no").\
@@ -375,7 +374,7 @@ def bm_interface_get_by_vif_uuid(context, vif_uuid):
     return result
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_interface_get_all_by_bm_node_id(context, bm_node_id):
     result = model_query(context, models.BareMetalInterface,
                          read_deleted="no").\
@@ -388,7 +387,7 @@ def bm_interface_get_all_by_bm_node_id(context, bm_node_id):
     return result
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_deployment_create(context, key, image_path, pxe_config_path, root_mb,
                          swap_mb):
     ref = models.BareMetalDeployment()
@@ -401,7 +400,7 @@ def bm_deployment_create(context, key, image_path, pxe_config_path, root_mb,
     return ref.id
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_deployment_get(context, dep_id):
     result = model_query(context, models.BareMetalDeployment,
                          read_deleted="no").\
@@ -410,7 +409,7 @@ def bm_deployment_get(context, dep_id):
     return result
 
 
-@require_admin_context
+@sqlalchemy_api.require_admin_context
 def bm_deployment_destroy(context, dep_id):
     model_query(context, models.BareMetalDeployment).\
                 filter_by(id=dep_id).\
diff --git a/nova/virt/baremetal/db/sqlalchemy/migration.py b/nova/virt/baremetal/db/sqlalchemy/migration.py
index 929793e70d..cfc26c04c4 100644
--- a/nova/virt/baremetal/db/sqlalchemy/migration.py
+++ b/nova/virt/baremetal/db/sqlalchemy/migration.py
@@ -25,7 +25,7 @@ import sqlalchemy
 from nova import exception
 from nova.openstack.common import log as logging
 from nova.virt.baremetal.db import migration
-from nova.virt.baremetal.db.sqlalchemy.session import get_engine
+from nova.virt.baremetal.db.sqlalchemy import session
 
 LOG = logging.getLogger(__name__)
 
@@ -71,24 +71,25 @@ def db_sync(version=None):
     current_version = db_version()
     repository = _find_migrate_repo()
     if version is None or version > current_version:
-        return versioning_api.upgrade(get_engine(), repository, version)
+        return versioning_api.upgrade(session.get_engine(), repository,
+                version)
     else:
-        return versioning_api.downgrade(get_engine(), repository,
+        return versioning_api.downgrade(session.get_engine(), repository,
                                         version)
 
 
 def db_version():
     repository = _find_migrate_repo()
     try:
-        return versioning_api.db_version(get_engine(), repository)
+        return versioning_api.db_version(session.get_engine(), repository)
     except versioning_exceptions.DatabaseNotControlledError:
         meta = sqlalchemy.MetaData()
-        engine = get_engine()
+        engine = session.get_engine()
         meta.reflect(bind=engine)
         tables = meta.tables
         if len(tables) == 0:
             db_version_control(migration.INIT_VERSION)
-            return versioning_api.db_version(get_engine(), repository)
+            return versioning_api.db_version(session.get_engine(), repository)
         else:
             # Some pre-Essex DB's may not be version controlled.
             # Require them to upgrade using Essex first.
@@ -98,7 +99,7 @@ def db_version():
 
 def db_version_control(version=None):
     repository = _find_migrate_repo()
-    versioning_api.version_control(get_engine(), repository, version)
+    versioning_api.version_control(session.get_engine(), repository, version)
     return version
 
 
diff --git a/nova/virt/baremetal/fake.py b/nova/virt/baremetal/fake.py
index 7a400af6fa..b3f39fdc3d 100644
--- a/nova/virt/baremetal/fake.py
+++ b/nova/virt/baremetal/fake.py
@@ -17,7 +17,7 @@
 #    under the License.
 
 from nova.virt.baremetal import base
-from nova.virt.firewall import NoopFirewallDriver
+from nova.virt import firewall
 
 
 class FakeDriver(base.NodeDriver):
@@ -52,7 +52,7 @@ class FakePowerManager(base.PowerManager):
         super(FakePowerManager, self).__init__(**kwargs)
 
 
-class FakeFirewallDriver(NoopFirewallDriver):
+class FakeFirewallDriver(firewall.NoopFirewallDriver):
 
     def __init__(self):
         super(FakeFirewallDriver, self).__init__()
diff --git a/nova/virt/baremetal/ipmi.py b/nova/virt/baremetal/ipmi.py
index 393b3657b9..5d4a87625d 100644
--- a/nova/virt/baremetal/ipmi.py
+++ b/nova/virt/baremetal/ipmi.py
@@ -25,7 +25,7 @@ import os
 import stat
 import tempfile
 
-from nova.exception import InvalidParameterValue
+from nova import exception
 from nova.openstack.common import cfg
 from nova.openstack.common import log as logging
 from nova import paths
@@ -104,13 +104,17 @@ class IPMI(base.PowerManager):
         self.port = node['terminal_port']
 
         if self.node_id == None:
-            raise InvalidParameterValue(_("Node id not supplied to IPMI"))
+            raise exception.InvalidParameterValue(_("Node id not supplied "
+                "to IPMI"))
         if self.address == None:
-            raise InvalidParameterValue(_("Address not supplied to IPMI"))
+            raise exception.InvalidParameterValue(_("Address not supplied "
+                "to IPMI"))
         if self.user == None:
-            raise InvalidParameterValue(_("User not supplied to IPMI"))
+            raise exception.InvalidParameterValue(_("User not supplied "
+                "to IPMI"))
         if self.password == None:
-            raise InvalidParameterValue(_("Password not supplied to IPMI"))
+            raise exception.InvalidParameterValue(_("Password not supplied "
+                "to IPMI"))
 
     def _exec_ipmitool(self, command):
         args = ['ipmitool',
diff --git a/nova/virt/baremetal/pxe.py b/nova/virt/baremetal/pxe.py
index 0daac1d463..91de43dd1a 100644
--- a/nova/virt/baremetal/pxe.py
+++ b/nova/virt/baremetal/pxe.py
@@ -67,7 +67,8 @@ CHEETAH = None
 def _get_cheetah():
     global CHEETAH
     if CHEETAH is None:
-        from Cheetah.Template import Template as CHEETAH
+        from Cheetah import Template
+        CHEETAH = Template.Template
     return CHEETAH
 
 
diff --git a/nova/virt/libvirt/__init__.py b/nova/virt/libvirt/__init__.py
index 00f4fd6b02..535d6c7297 100644
--- a/nova/virt/libvirt/__init__.py
+++ b/nova/virt/libvirt/__init__.py
@@ -14,4 +14,6 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from nova.virt.libvirt.driver import LibvirtDriver
+from nova.virt.libvirt import driver
+
+LibvirtDriver = driver.LibvirtDriver
diff --git a/nova/virt/powervm/__init__.py b/nova/virt/powervm/__init__.py
index 83bbcd2899..1b63f83109 100644
--- a/nova/virt/powervm/__init__.py
+++ b/nova/virt/powervm/__init__.py
@@ -26,4 +26,6 @@ refer to the IBM Redbook[1] publication.
     May 2011. <http://www.redbooks.ibm.com/abstracts/sg247940.html>
 """
 
-from nova.virt.powervm.driver import PowerVMDriver
+from nova.virt.powervm import driver
+
+PowerVMDriver = driver.PowerVMDriver
diff --git a/nova/virt/vmwareapi/__init__.py b/nova/virt/vmwareapi/__init__.py
index 66e7d9b027..37d816f8c0 100644
--- a/nova/virt/vmwareapi/__init__.py
+++ b/nova/virt/vmwareapi/__init__.py
@@ -18,4 +18,6 @@
 :mod:`vmwareapi` -- Nova support for VMware ESX/ESXi Server through VMware API.
 """
 # NOTE(sdague) for nicer compute_driver specification
-from nova.virt.vmwareapi.driver import VMwareESXDriver
+from nova.virt.vmwareapi import driver
+
+VMwareESXDriver = driver.VMwareESXDriver
diff --git a/nova/virt/xenapi/__init__.py b/nova/virt/xenapi/__init__.py
index 6a56a918c0..3853f09f2c 100644
--- a/nova/virt/xenapi/__init__.py
+++ b/nova/virt/xenapi/__init__.py
@@ -18,4 +18,6 @@
 :mod:`xenapi` -- Nova support for XenServer and XCP through XenAPI
 ==================================================================
 """
-from nova.virt.xenapi.driver import XenAPIDriver
+from nova.virt.xenapi import driver
+
+XenAPIDriver = driver.XenAPIDriver