Drop xenapi session.get_imported_xenapi()

Historically it was used to allow the xenapi fake module to be inserted
in place of the real XenAPI module. However, it was used inconsistently
and is unnecessary now that the session carries that information as well.

Remove it by using the session.XenAPI attribute consistently, and then
removing the stubs and ensuring that the fake module gets inserted
directly into sys.modules.

Change-Id: Id058e19eb7d932abf7b07a1e4324637a8d4b2ea6

8 files changed, 50 insertions, 58 deletions

diff --git a/nova/tests/test_xenapi.py b/nova/tests/test_xenapi.py
index 5181e6385..c3a311e0e 100644
--- a/nova/tests/test_xenapi.py
+++ b/nova/tests/test_xenapi.py
@@ -134,7 +134,7 @@ def stub_vm_utils_with_vdi_attached_here(function, should_return=True):
     return decorated_function
 
 
-class XenAPIVolumeTestCase(test.TestCase):
+class XenAPIVolumeTestCase(stubs.XenAPITestBase):
     """Unit tests for Volume operations."""
     def setUp(self):
         super(XenAPIVolumeTestCase, self).setUp()
@@ -147,7 +147,6 @@ class XenAPIVolumeTestCase(test.TestCase):
                 firewall_driver='nova.virt.xenapi.firewall.'
                                 'Dom0IptablesFirewallDriver')
         db_fakes.stub_out_db_instance_api(self.stubs)
-        xenapi_fake.reset()
         self.instance_values = {'id': 1,
                   'project_id': self.user_id,
                   'user_id': 'fake',
@@ -252,7 +251,7 @@ class XenAPIVolumeTestCase(test.TestCase):
                           '/dev/sdc')
 
 
-class XenAPIVMTestCase(test.TestCase):
+class XenAPIVMTestCase(stubs.XenAPITestBase):
     """Unit tests for VM operations."""
     def setUp(self):
         super(XenAPIVMTestCase, self).setUp()
@@ -262,7 +261,6 @@ class XenAPIVMTestCase(test.TestCase):
                    instance_name_template='%d',
                    firewall_driver='nova.virt.xenapi.firewall.'
                                    'Dom0IptablesFirewallDriver')
-        xenapi_fake.reset()
         xenapi_fake.create_local_srs()
         xenapi_fake.create_local_pifs()
         db_fakes.stub_out_db_instance_api(self.stubs)
@@ -868,7 +866,7 @@ class XenAPIDiffieHellmanTestCase(test.TestCase):
         self._test_encryption(''.join(['abcd' for i in xrange(1024)]))
 
 
-class XenAPIMigrateInstance(test.TestCase):
+class XenAPIMigrateInstance(stubs.XenAPITestBase):
     """Unit test for verifying migration-related actions."""
 
     def setUp(self):
@@ -880,7 +878,6 @@ class XenAPIMigrateInstance(test.TestCase):
                                 'Dom0IptablesFirewallDriver')
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
         db_fakes.stub_out_db_instance_api(self.stubs)
-        xenapi_fake.reset()
         xenapi_fake.create_network('fake', FLAGS.flat_network_bridge)
         self.user_id = 'fake'
         self.project_id = 'fake'
@@ -1122,7 +1119,7 @@ class CompareVersionTestCase(test.TestCase):
         self.assertTrue(vmops.cmp_version('1.2.3', '1.2.3.4') < 0)
 
 
-class XenAPIHostTestCase(test.TestCase):
+class XenAPIHostTestCase(stubs.XenAPITestBase):
     """Tests HostState, which holds metrics from XenServer that get
     reported back to the Schedulers."""
 
@@ -1131,7 +1128,6 @@ class XenAPIHostTestCase(test.TestCase):
         self.flags(xenapi_connection_url='test_url',
                    xenapi_connection_password='test_pass')
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        xenapi_fake.reset()
         xenapi_fake.create_local_srs()
         self.conn = xenapi_conn.XenAPIDriver(False)
 
@@ -1175,7 +1171,7 @@ class XenAPIHostTestCase(test.TestCase):
         self._test_host_action(self.conn.set_host_enabled, False, 'disabled')
 
 
-class XenAPIAutoDiskConfigTestCase(test.TestCase):
+class XenAPIAutoDiskConfigTestCase(stubs.XenAPITestBase):
     def setUp(self):
         super(XenAPIAutoDiskConfigTestCase, self).setUp()
         self.flags(target_host='127.0.0.1',
@@ -1184,7 +1180,6 @@ class XenAPIAutoDiskConfigTestCase(test.TestCase):
                    firewall_driver='nova.virt.xenapi.firewall.'
                                    'Dom0IptablesFirewallDriver')
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        xenapi_fake.reset()
         self.conn = xenapi_conn.XenAPIDriver(False)
 
         self.user_id = 'fake'
@@ -1266,7 +1261,7 @@ class XenAPIAutoDiskConfigTestCase(test.TestCase):
         self.assertIsPartitionCalled(True)
 
 
-class XenAPIGenerateLocal(test.TestCase):
+class XenAPIGenerateLocal(stubs.XenAPITestBase):
     """Test generating of local disks, like swap and ephemeral"""
     def setUp(self):
         super(XenAPIGenerateLocal, self).setUp()
@@ -1278,7 +1273,6 @@ class XenAPIGenerateLocal(test.TestCase):
                                    'Dom0IptablesFirewallDriver')
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
         db_fakes.stub_out_db_instance_api(self.stubs)
-        xenapi_fake.reset()
         self.conn = xenapi_conn.XenAPIDriver(False)
 
         self.user_id = 'fake'
@@ -1343,7 +1337,7 @@ class XenAPIGenerateLocal(test.TestCase):
         self.assertCalled(instance)
 
 
-class XenAPIBWUsageTestCase(test.TestCase):
+class XenAPIBWUsageTestCase(stubs.XenAPITestBase):
     def setUp(self):
         super(XenAPIBWUsageTestCase, self).setUp()
         self.stubs.Set(vm_utils, 'compile_metrics',
@@ -1354,7 +1348,6 @@ class XenAPIBWUsageTestCase(test.TestCase):
                    firewall_driver='nova.virt.xenapi.firewall.'
                                    'Dom0IptablesFirewallDriver')
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        xenapi_fake.reset()
         self.conn = xenapi_conn.XenAPIDriver(False)
 
     @classmethod
@@ -1378,7 +1371,7 @@ class XenAPIBWUsageTestCase(test.TestCase):
 # TODO(salvatore-orlando): this class and
 # nova.tests.test_libvirt.IPTablesFirewallDriverTestCase share a lot of code.
 # Consider abstracting common code in a base class for firewall driver testing.
-class XenAPIDom0IptablesFirewallTestCase(test.TestCase):
+class XenAPIDom0IptablesFirewallTestCase(stubs.XenAPITestBase):
 
     _in_nat_rules = [
       '# Generated by iptables-save v1.4.10 on Sat Feb 19 00:03:19 2011',
@@ -1424,7 +1417,6 @@ class XenAPIDom0IptablesFirewallTestCase(test.TestCase):
                    instance_name_template='%d',
                    firewall_driver='nova.virt.xenapi.firewall.'
                                    'Dom0IptablesFirewallDriver')
-        xenapi_fake.reset()
         xenapi_fake.create_local_srs()
         xenapi_fake.create_local_pifs()
         self.user_id = 'mappin'
@@ -1679,12 +1671,8 @@ class XenAPIDom0IptablesFirewallTestCase(test.TestCase):
         self.assertEqual(1, len(rules))
 
 
-class XenAPISRSelectionTestCase(test.TestCase):
+class XenAPISRSelectionTestCase(stubs.XenAPITestBase):
     """Unit tests for testing we find the right SR."""
-    def setUp(self):
-        super(XenAPISRSelectionTestCase, self).setUp()
-        xenapi_fake.reset()
-
     def test_safe_find_sr_raise_exception(self):
         """Ensure StorageRepositoryNotFound is raise when wrong filter."""
         self.flags(sr_matching_filter='yadayadayada')
@@ -1733,7 +1721,7 @@ class XenAPISRSelectionTestCase(test.TestCase):
                          expected)
 
 
-class XenAPIAggregateTestCase(test.TestCase):
+class XenAPIAggregateTestCase(stubs.XenAPITestBase):
     """Unit tests for aggregate operations."""
     def setUp(self):
         super(XenAPIAggregateTestCase, self).setUp()
@@ -1744,7 +1732,6 @@ class XenAPIAggregateTestCase(test.TestCase):
                    firewall_driver='nova.virt.xenapi.firewall.'
                                    'Dom0IptablesFirewallDriver',
                    host='host')
-        xenapi_fake.reset()
         host_ref = xenapi_fake.get_all('host')[0]
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
         self.context = context.get_admin_context()
diff --git a/nova/tests/test_xensm.py b/nova/tests/test_xensm.py
index 18be0266c..659a7b92f 100644
--- a/nova/tests/test_xensm.py
+++ b/nova/tests/test_xensm.py
@@ -35,7 +35,7 @@ LOG = logging.getLogger(__name__)
 FLAGS = flags.FLAGS
 
 
-class XenSMTestCase(test.TestCase):
+class XenSMTestCase(stubs.XenAPITestBase):
     """Unit tests for Xen Storage Manager Volume operations."""
 
     def _get_sm_backend_params(self):
diff --git a/nova/tests/xenapi/stubs.py b/nova/tests/xenapi/stubs.py
index 255f26a22..275e3ce63 100644
--- a/nova/tests/xenapi/stubs.py
+++ b/nova/tests/xenapi/stubs.py
@@ -16,8 +16,10 @@
 """Stubouts, mocks and fixtures for the test suite"""
 
 import random
+import sys
 
 from nova.openstack.common import jsonutils
+from nova import test
 import nova.tests.image.fake
 from nova.virt.xenapi import connection as xenapi_conn
 from nova.virt.xenapi import fake
@@ -51,17 +53,9 @@ def stubout_instance_snapshot(stubs):
 
 
 def stubout_session(stubs, cls, product_version=(5, 6, 2), **opt_args):
-    """Stubs out three methods from XenAPISession"""
-    def fake_import(self):
-        """Stubs out get_imported_xenapi of XenAPISession"""
-        fake_module = 'nova.virt.xenapi.fake'
-        from_list = ['fake']
-        return __import__(fake_module, globals(), locals(), from_list, -1)
-
+    """Stubs out methods from XenAPISession"""
     stubs.Set(xenapi_conn.XenAPISession, '_create_session',
               lambda s, url: cls(url, **opt_args))
-    stubs.Set(xenapi_conn.XenAPISession, 'get_imported_xenapi',
-              fake_import)
     stubs.Set(xenapi_conn.XenAPISession, '_get_product_version',
               lambda s: product_version)
 
@@ -363,3 +357,22 @@ def stub_out_migration_methods(stubs):
     stubs.Set(vm_utils, 'get_vdi_for_vm_safely', fake_get_vdi)
     stubs.Set(vm_utils, 'get_sr_path', fake_get_sr_path)
     stubs.Set(vm_utils, 'generate_ephemeral', fake_generate_ephemeral)
+
+
+class XenAPITestBase(test.TestCase):
+    def setUp(self):
+        super(XenAPITestBase, self).setUp()
+
+        self.orig_XenAPI = sys.modules.get('XenAPI')
+        sys.modules['XenAPI'] = fake
+
+        fake.reset()
+
+    def tearDown(self):
+        if self.orig_XenAPI is not None:
+            sys.modules['XenAPI'] = self.orig_XenAPI
+            self.orig_XenAPI = None
+        else:
+            sys.modules.pop('XenAPI')
+
+        super(XenAPITestBase, self).tearDown()
diff --git a/nova/virt/xenapi/connection.py b/nova/virt/xenapi/connection.py
index 2777fa883..4d29b7ed8 100644
--- a/nova/virt/xenapi/connection.py
+++ b/nova/virt/xenapi/connection.py
@@ -500,7 +500,8 @@ class XenAPISession(object):
     """The session to invoke XenAPI SDK calls"""
 
     def __init__(self, url, user, pw):
-        self.XenAPI = self.get_imported_xenapi()
+        import XenAPI
+        self.XenAPI = XenAPI
         self._sessions = queue.Queue()
         self.is_slave = False
         exception = self.XenAPI.Failure(_("Unable to log in to XenAPI "
@@ -558,10 +559,6 @@ class XenAPISession(object):
         product_version = software_version['product_version']
         return tuple(int(part) for part in product_version.split('.'))
 
-    def get_imported_xenapi(self):
-        """Stubout point. This can be replaced with a mock xenapi module."""
-        return __import__('XenAPI')
-
     def get_session_id(self):
         """Return a string session_id.  Used for vnc consoles."""
         with self._get_session() as session:
diff --git a/nova/virt/xenapi/host.py b/nova/virt/xenapi/host.py
index 7fe8a7b77..4633695fd 100644
--- a/nova/virt/xenapi/host.py
+++ b/nova/virt/xenapi/host.py
@@ -38,7 +38,6 @@ class Host(object):
     Implements host related operations.
     """
     def __init__(self, session):
-        self.XenAPI = session.get_imported_xenapi()
         self._session = session
 
     def host_power_action(self, _host, action):
@@ -95,7 +94,7 @@ class Host(object):
                     notifications.send_update(ctxt, old_ref, new_ref)
 
                     break
-                except self.XenAPI.Failure:
+                except self._session.XenAPI.Failure:
                     LOG.exception('Unable to migrate VM %(vm_ref)s'
                                   'from %(host)s' % locals())
                     (old_ref, new_ref) = db.instance_update_and_get_original(
@@ -173,7 +172,6 @@ def call_xenhost(session, method, arg_dict):
     out that behavior.
     """
     # Create a task ID as something that won't match any instance ID
-    XenAPI = session.get_imported_xenapi()
     try:
         result = session.call_plugin('xenhost', method, args=arg_dict)
         if not result:
@@ -182,7 +180,7 @@ def call_xenhost(session, method, arg_dict):
     except ValueError:
         LOG.exception(_("Unable to get updated status"))
         return None
-    except XenAPI.Failure as e:
+    except session.XenAPI.Failure as e:
         LOG.error(_("The call to %(method)s returned "
                     "an error: %(e)s.") % locals())
         return e.details[1]
diff --git a/nova/virt/xenapi/pool.py b/nova/virt/xenapi/pool.py
index cb00faed5..07a03d029 100644
--- a/nova/virt/xenapi/pool.py
+++ b/nova/virt/xenapi/pool.py
@@ -48,7 +48,6 @@ class ResourcePool(object):
     Implements resource pool operations.
     """
     def __init__(self, session):
-        self.XenAPI = session.get_imported_xenapi()
         host_ref = session.get_xenapi_host()
         host_rec = session.call_xenapi('host.get_record', host_ref)
         self._host_name = host_rec['hostname']
@@ -139,7 +138,7 @@ class ResourcePool(object):
                     'master_user': FLAGS.xenapi_connection_username,
                     'master_pass': FLAGS.xenapi_connection_password, }
             self._session.call_plugin('xenhost', 'host_join', args)
-        except self.XenAPI.Failure as e:
+        except self._session.XenAPI.Failure as e:
             LOG.error(_("Pool-Join failed: %(e)s") % locals())
             raise exception.AggregateError(aggregate_id=aggregate_id,
                                            action='add_to_aggregate',
@@ -158,7 +157,7 @@ class ResourcePool(object):
 
             host_ref = self._session.call_xenapi('host.get_by_uuid', host_uuid)
             self._session.call_xenapi("pool.eject", host_ref)
-        except self.XenAPI.Failure as e:
+        except self._session.XenAPI.Failure as e:
             LOG.error(_("Pool-eject failed: %(e)s") % locals())
             raise exception.AggregateError(aggregate_id=aggregate_id,
                                            action='remove_from_aggregate',
@@ -170,7 +169,7 @@ class ResourcePool(object):
             pool_ref = self._session.call_xenapi("pool.get_all")[0]
             self._session.call_xenapi("pool.set_name_label",
                                       pool_ref, aggregate_name)
-        except self.XenAPI.Failure as e:
+        except self._session.XenAPI.Failure as e:
             LOG.error(_("Unable to set up pool: %(e)s.") % locals())
             raise exception.AggregateError(aggregate_id=aggregate_id,
                                            action='add_to_aggregate',
@@ -181,7 +180,7 @@ class ResourcePool(object):
         try:
             pool_ref = self._session.call_xenapi('pool.get_all')[0]
             self._session.call_xenapi('pool.set_name_label', pool_ref, '')
-        except self.XenAPI.Failure as e:
+        except self._session.XenAPI.Failure as e:
             LOG.error(_("Pool-set_name_label failed: %(e)s") % locals())
             raise exception.AggregateError(aggregate_id=aggregate_id,
                                            action='remove_from_aggregate',
diff --git a/nova/virt/xenapi/vmops.py b/nova/virt/xenapi/vmops.py
index 85fe73cd8..6af2ac9e0 100644
--- a/nova/virt/xenapi/vmops.py
+++ b/nova/virt/xenapi/vmops.py
@@ -152,7 +152,6 @@ class VMOps(object):
     Management class for VM-related tasks
     """
     def __init__(self, session):
-        self.XenAPI = session.get_imported_xenapi()
         self.compute_api = compute.API()
         self._session = session
         self.poll_rescue_last_ran = None
@@ -619,7 +618,7 @@ class VMOps(object):
             template_vm_ref, template_vdi_uuids = vm_utils.create_snapshot(
                     self._session, instance, vm_ref, label)
             return template_vm_ref, template_vdi_uuids
-        except self.XenAPI.Failure, exc:
+        except self._session.XenAPI.Failure, exc:
             LOG.error(_("Unable to Snapshot instance: %(exc)s"), locals(),
                       instance=instance)
             raise
@@ -635,7 +634,7 @@ class VMOps(object):
             _params = {'params': pickle.dumps(params)}
             self._session.call_plugin('migration', 'transfer_vhd',
                                       _params)
-        except self.XenAPI.Failure:
+        except self._session.XenAPI.Failure:
             msg = _("Failed to transfer vhd to new host")
             raise exception.MigrationError(reason=msg)
 
@@ -977,7 +976,7 @@ class VMOps(object):
                 self._session.call_xenapi('VM.hard_shutdown', vm_ref)
             else:
                 self._session.call_xenapi('VM.clean_shutdown', vm_ref)
-        except self.XenAPI.Failure, exc:
+        except self._session.XenAPI.Failure, exc:
             LOG.exception(exc)
 
     def _find_root_vdi_ref(self, vm_ref):
@@ -1038,7 +1037,7 @@ class VMOps(object):
         """Destroys a VM record."""
         try:
             self._session.call_xenapi('VM.destroy', vm_ref)
-        except self.XenAPI.Failure, exc:
+        except self._session.XenAPI.Failure, exc:
             LOG.exception(exc)
             return
 
@@ -1492,7 +1491,7 @@ class VMOps(object):
         args.update(addl_args)
         try:
             return self._session.call_plugin(plugin, method, args)
-        except self.XenAPI.Failure, e:
+        except self._session.XenAPI.Failure, e:
             err_msg = e.details[-1].splitlines()[-1]
             if 'TIMEOUT:' in err_msg:
                 LOG.error(_('TIMEOUT: The call to %(method)s timed out. '
diff --git a/nova/virt/xenapi/volumeops.py b/nova/virt/xenapi/volumeops.py
index 412b89be5..587c5877a 100644
--- a/nova/virt/xenapi/volumeops.py
+++ b/nova/virt/xenapi/volumeops.py
@@ -33,7 +33,6 @@ class VolumeOps(object):
     """
 
     def __init__(self, session):
-        self.XenAPI = session.get_imported_xenapi()
         self._session = session
 
     def create_volume_for_sm(self, volume, sr_uuid):
@@ -42,7 +41,7 @@ class VolumeOps(object):
         sm_vol_rec = {}
         try:
             sr_ref = self._session.call_xenapi("SR.get_by_uuid", sr_uuid)
-        except self.XenAPI.Failure, exc:
+        except self._session.XenAPI.Failure, exc:
             LOG.exception(exc)
             raise volume_utils.StorageError(_('Unable to get SR using uuid'))
         #Create VDI
@@ -149,7 +148,7 @@ class VolumeOps(object):
         try:
             sr_ref = self.introduce_sr(uuid, label, sr_params)
             LOG.debug(_('Introduced %(label)s as %(sr_ref)s.') % locals())
-        except self.XenAPI.Failure, exc:
+        except self._session.XenAPI.Failure, exc:
             LOG.exception(exc)
             raise volume_utils.StorageError(
                                 _('Unable to introduce Storage Repository'))
@@ -177,7 +176,7 @@ class VolumeOps(object):
         try:
             vbd_ref = vm_utils.create_vbd(self._session, vm_ref, vdi_ref,
                                           dev_number, bootable=False)
-        except self.XenAPI.Failure, exc:
+        except self._session.XenAPI.Failure, exc:
             LOG.exception(exc)
             self.forget_sr(uuid)
             raise Exception(_('Unable to use SR %(sr_ref)s for'
@@ -185,7 +184,7 @@ class VolumeOps(object):
 
         try:
             self._session.call_xenapi("VBD.plug", vbd_ref)
-        except self.XenAPI.Failure, exc:
+        except self._session.XenAPI.Failure, exc:
             LOG.exception(exc)
             self.forget_sr(uuid)
             raise Exception(_('Unable to attach volume to instance %s')