Make Xen code py3-compatible

A couple places in the Xen code have been using syntax that is
python2-specific. This replaces those instances with code that will
work in both python2 and python3.

PEP 3108 [1] moves urllib.urlopen to urllib.request.urlopen. The six
module is used in order to work in both python2 and python3 [2].

PEP 3110 [3] changed the grammar for except clauses, such that the
'as' keyword is now required in place of a comma when specifying an
exception variable.

[1] https://www.python.org/dev/peps/pep-3108/
[2] https://pythonhosted.org/six/#module-six.moves.urllib.request
[3] https://www.python.org/dev/peps/pep-3110/

Change-Id: I1235d767718a4207f4cef3e5b140319d003ad7b0

nova/virt/xenapi/vm_utils.py

@@ -23,7 +23,6 @@ import contextlib
 import math
 import os
 import time
-import urllib
 from xml.dom import minidom
 from xml.parsers import expat
 
@@ -42,6 +41,7 @@ from oslo_utils import versionutils
 import six
 from six.moves import range
 import six.moves.urllib.parse as urlparse
+import six.moves.urllib.request as urlrequest
 
 from nova.api.metadata import base as instance_metadata
 from nova.compute import power_state
@@ -1950,7 +1950,7 @@ def _get_rrd_server():
 def _get_rrd(server, vm_uuid):
     """Return the VM RRD XML as a string."""
     try:
-        xml = urllib.urlopen("%s://%s:%s@%s/vm_rrd?uuid=%s" % (
+        xml = urlrequest.urlopen("%s://%s:%s@%s/vm_rrd?uuid=%s" % (
             server[0],
             CONF.xenserver.connection_username,
             CONF.xenserver.connection_password,

tools/xenserver/vm_vdi_cleaner.py

@@ -105,7 +105,7 @@ def _get_applicable_vm_recs(xenapi):
     for vm_ref in call_xenapi(xenapi, 'VM.get_all'):
         try:
             vm_rec = call_xenapi(xenapi, 'VM.get_record', vm_ref)
-        except XenAPI.Failure, e:
+        except XenAPI.Failure as e:
             if e.details[0] != 'HANDLE_INVALID':
                 raise
             continue
@@ -161,7 +161,7 @@ def _find_vdis_connected_to_vm(xenapi, connected_vdi_uuids):
                 try:
                     cur_vdi_rec = call_xenapi(xenapi, 'VDI.get_record',
                             cur_vdi_ref)
-                except XenAPI.Failure, e:
+                except XenAPI.Failure as e:
                     if e.details[0] != 'HANDLE_INVALID':
                         raise
                     break
@@ -176,7 +176,7 @@ def _find_vdis_connected_to_vm(xenapi, connected_vdi_uuids):
         for vbd_ref in vbd_refs:
             try:
                 vbd_rec = call_xenapi(xenapi, 'VBD.get_record', vbd_ref)
-            except XenAPI.Failure, e:
+            except XenAPI.Failure as e:
                 if e.details[0] != 'HANDLE_INVALID':
                     raise
                 continue
@@ -191,7 +191,7 @@ def _find_vdis_connected_to_vm(xenapi, connected_vdi_uuids):
 
             try:
                 vdi_rec = call_xenapi(xenapi, 'VDI.get_record', vbd_vdi_ref)
-            except XenAPI.Failure, e:
+            except XenAPI.Failure as e:
                 if e.details[0] != 'HANDLE_INVALID':
                     raise
                 continue
@@ -210,7 +210,7 @@ def _find_all_vdis_and_system_vdis(xenapi, all_vdi_uuids, connected_vdi_uuids):
     for vdi_ref in call_xenapi(xenapi, 'VDI.get_all'):
         try:
             vdi_rec = call_xenapi(xenapi, 'VDI.get_record', vdi_ref)
-        except XenAPI.Failure, e:
+        except XenAPI.Failure as e:
             if e.details[0] != 'HANDLE_INVALID':
                 raise
             continue
@@ -254,7 +254,7 @@ def clean_orphaned_vdis(xenapi, vdi_uuids):
         vdi_ref = call_xenapi(xenapi, 'VDI.get_by_uuid', vdi_uuid)
         try:
             call_xenapi(xenapi, 'VDI.destroy', vdi_ref)
-        except XenAPI.Failure, exc:
+        except XenAPI.Failure as exc:
             sys.stderr.write("Skipping %s: %s" % (vdi_uuid, exc))