xenapi: Remove unecessary exception handling

The volume code was catching exceptions from the XenAPI only to re-raise
more-generic StorageError exceptions. This practice makes it much more
difficult to discover the root-cause of issues in production by making
the message in the instance-faults table less useful.

The solution is to have the original root-cause exception propogate all
the way up to the instance-faults table where the developer will be able
to make sense of it.

Other cleanups:

* Remove useless logging and stop logging opaque-refs in some places

* Remove dead code (create_iscsi_storage)

* Remove one-off functions (forget_sr_if_present,
  introduce_sr_unless_present); just use forget_sr and introduce_sr

* Removed unused `exception` import

* Added Openstack copyright lines

Future Work:

There are lots of other places where unecessary exception handling is
occuring; this patch just addresses this in the attach/detach code-path.

Fixes bug 1122733

Change-Id: I8c382fb505303e604ff2e86afcf302efe3d6851d

1 files changed, 18 insertions, 14 deletions

diff --git a/nova/tests/virt/xenapi/test_volumeops.py b/nova/tests/virt/xenapi/test_volumeops.py
index 844ae8459..3497babf2 100644
--- a/nova/tests/virt/xenapi/test_volumeops.py
+++ b/nova/tests/virt/xenapi/test_volumeops.py
@@ -14,6 +14,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import collections
+
 from nova import test
 from nova.tests.xenapi import stubs
 from nova.virt.xenapi import volumeops
@@ -125,31 +127,33 @@ class VolumeAttachTestCase(test.TestCase):
         vm_ref = 'vm_ref'
         dev_number = 1
 
-        called = {'xenapi': False}
+        called = collections.defaultdict(bool)
 
-        def fake_call_xenapi(self, *args, **kwargs):
-            # Only used for VBD.plug in this code path.
-            called['xenapi'] = True
-            raise Exception()
+        def fake_call_xenapi(self, method, *args, **kwargs):
+            called[method] = True
 
         self.stubs.Set(ops._session, 'call_xenapi', fake_call_xenapi)
 
         self.mox.StubOutWithMock(volumeops.volume_utils, 'parse_sr_info')
-        self.mox.StubOutWithMock(
-            volumeops.volume_utils, 'introduce_sr_unless_present')
-        self.mox.StubOutWithMock(volumeops.volume_utils, 'introduce_vdi')
-        self.mox.StubOutWithMock(volumeops.vm_utils, 'create_vbd')
-
         volumeops.volume_utils.parse_sr_info(
             connection_data, sr_label).AndReturn(
                 tuple([sr_uuid, sr_label, sr_params]))
 
-        volumeops.volume_utils.introduce_sr_unless_present(
+        self.mox.StubOutWithMock(
+            volumeops.volume_utils, 'find_sr_by_uuid')
+        volumeops.volume_utils.find_sr_by_uuid(session, sr_uuid).AndReturn(
+                None)
+
+        self.mox.StubOutWithMock(
+            volumeops.volume_utils, 'introduce_sr')
+        volumeops.volume_utils.introduce_sr(
             session, sr_uuid, sr_label, sr_params).AndReturn(sr_ref)
 
+        self.mox.StubOutWithMock(volumeops.volume_utils, 'introduce_vdi')
         volumeops.volume_utils.introduce_vdi(
-            session, sr_ref, vdi_uuid, None).AndReturn(vdi_ref)
+            session, sr_ref, vdi_uuid=vdi_uuid).AndReturn(vdi_ref)
 
+        self.mox.StubOutWithMock(volumeops.vm_utils, 'create_vbd')
         volumeops.vm_utils.create_vbd(
             session, vm_ref, vdi_ref, dev_number,
             bootable=False, osvol=True).AndReturn(vbd_ref)
@@ -157,6 +161,6 @@ class VolumeAttachTestCase(test.TestCase):
         self.mox.ReplayAll()
 
         ops._connect_volume(connection_data, dev_number, instance_name,
-                           vm_ref, hotplug=False)
+                            vm_ref, hotplug=False)
 
-        self.assertEquals(False, called['xenapi'])
+        self.assertEquals(False, called['VBD.plug'])