Improve Python 3.x compatibility

Mechanical translation of the deprecated
except x,y: construct with except x as y:
The latter works with any Python >= 2.6.
Add Hacking check.

Change-Id: I845829d97d379c1cd9b3a77e7e5786586f263b64

HACKING.rst

@@ -211,6 +211,25 @@ Example::
     LOG.error(msg % {"s_id": "1234", "m_key": "imageId"})
 
 
+Python 3.x compatibility
+------------------------
+Nova code should stay Python 3.x compatible. That means all Python 2.x-only
+constructs should be avoided. An example is
+
+    except x,y:
+
+Use
+
+    except x as y:
+
+instead. Other Python 3.x compatility issues, like e.g. print operator
+can be avoided in new code by using
+
+    from __future__ import print_function
+
+at the top of your module.
+
+
 Creating Unit Tests
 -------------------
 For every new feature, unit tests should be created that both test and

nova/api/ec2/__init__.py

@@ -251,7 +251,7 @@ class EC2KeystoneAuth(wsgi.Middleware):
             project_name = result['access']['token']['tenant'].get('name')
             roles = [role['name'] for role
                      in result['access']['user']['roles']]
-        except (AttributeError, KeyError), e:
+        except (AttributeError, KeyError) as e:
             LOG.exception(_("Keystone failure: %s") % e)
             msg = _("Failure communicating with keystone")
             return ec2_error(req, request_id, "Unauthorized", msg)

nova/api/openstack/compute/contrib/admin_actions.py

@@ -123,7 +123,7 @@ class AdminActionsController(wsgi.Controller):
         except exception.InstanceInvalidState as state_error:
             common.raise_http_conflict_for_instance_invalid_state(state_error,
                     'migrate')
-        except Exception, e:
+        except Exception as e:
             LOG.exception(_("Error in migrate %s"), e)
             raise exc.HTTPBadRequest()
         return webob.Response(status_int=202)

nova/api/openstack/compute/contrib/attach_interfaces.py

@@ -102,13 +102,13 @@ class InterfaceAttachmentController(object):
             LOG.audit(_("Attach interface"), instance=instance)
             network_info = self.compute_api.attach_interface(context,
                 instance, network_id, port_id, req_ip)
-        except exception.NotFound, e:
+        except exception.NotFound as e:
             LOG.exception(e)
             raise exc.HTTPNotFound()
         except NotImplementedError:
             msg = _("Network driver does not support this function.")
             raise webob.exc.HTTPNotImplemented(explanation=msg)
-        except exception.InterfaceAttachFailed, e:
+        except exception.InterfaceAttachFailed as e:
             LOG.exception(e)
             msg = _("Failed to attach interface")
             raise webob.exc.HTTPInternalServerError(explanation=msg)

nova/api/openstack/compute/contrib/flavor_access.py

@@ -191,7 +191,7 @@ class FlavorActionController(wsgi.Controller):
 
         try:
             flavors.remove_instance_type_access(id, tenant, context)
-        except exception.FlavorAccessNotFound, e:
+        except exception.FlavorAccessNotFound as e:
             raise webob.exc.HTTPNotFound(explanation=e.format_message())
 
         return _marshall_flavor_access(id)

nova/api/openstack/compute/contrib/flavormanage.py

@@ -42,7 +42,7 @@ class FlavorManageController(wsgi.Controller):
         try:
             flavor = flavors.get_instance_type_by_flavor_id(
                     id, read_deleted="no")
-        except exception.NotFound, e:
+        except exception.NotFound as e:
             raise webob.exc.HTTPNotFound(explanation=e.format_message())
 
         flavors.destroy(flavor['name'])

nova/cmd/baremetal_deploy_helper.py

@@ -201,7 +201,7 @@ def deploy(address, port, iqn, lun, image_path, pxe_config_path,
     login_iscsi(address, port, iqn)
     try:
         root_uuid = work_on_disk(dev, root_mb, swap_mb, image_path)
-    except processutils.ProcessExecutionError, err:
+    except processutils.ProcessExecutionError as err:
         # Log output if there was a error
         LOG.error("Cmd     : %s" % err.cmd)
         LOG.error("StdOut  : %s" % err.stdout)

nova/compute/manager.py

@@ -1774,7 +1774,7 @@ class ComputeManager(manager.SchedulerDependentManager):
                                reboot_type,
                                block_device_info=block_device_info,
                                bad_volumes_callback=bad_volumes_callback)
-        except Exception, exc:
+        except Exception as exc:
             LOG.error(_('Cannot reboot instance: %(exc)s'), locals(),
                       context=context, instance=instance)
             compute_utils.add_instance_fault_from_exc(context,
@@ -4114,7 +4114,7 @@ class ComputeManager(manager.SchedulerDependentManager):
                                         reservations=None):
         try:
             yield
-        except exception.InstanceFaultRollback, error:
+        except exception.InstanceFaultRollback as error:
             self._quota_rollback(context, reservations)
             msg = _("Setting instance back to ACTIVE after: %s")
             LOG.info(msg % error, instance_uuid=instance_uuid)
@@ -4122,7 +4122,7 @@ class ComputeManager(manager.SchedulerDependentManager):
                                   vm_state=vm_states.ACTIVE,
                                   task_state=None)
             raise error.inner_exception
-        except Exception, error:
+        except Exception as error:
             with excutils.save_and_reraise_exception():
                 self._quota_rollback(context, reservations)
                 msg = _('%s. Setting instance vm_state to ERROR')

nova/console/xvp.py

@@ -143,7 +143,7 @@ class XVPConsoleProxy(object):
                           '-p', CONF.console_xvp_pid,
                           '-c', CONF.console_xvp_conf,
                           '-l', CONF.console_xvp_log)
-        except processutils.ProcessExecutionError, err:
+        except processutils.ProcessExecutionError as err:
             LOG.error(_('Error starting xvp: %s') % err)
 
     def _xvp_restart(self):

nova/db/sqlalchemy/api.py

@@ -3739,7 +3739,7 @@ def instance_type_create(context, values):
         if 'flavorid' in e.columns:
             raise exception.InstanceTypeIdExists(flavor_id=values['flavorid'])
         raise exception.InstanceTypeExists(name=values['name'])
-    except Exception, e:
+    except Exception as e:
         raise db_exc.DBError(e)
 
     return _dict_with_extra_specs(instance_type_ref)
@@ -4505,7 +4505,7 @@ def s3_image_create(context, image_uuid):
         s3_image_ref = models.S3Image()
         s3_image_ref.update({'uuid': image_uuid})
         s3_image_ref.save()
-    except Exception, e:
+    except Exception as e:
         raise db_exc.DBError(e)
 
     return s3_image_ref

nova/exception.py

@@ -73,7 +73,7 @@ def wrap_exception(notifier=None, publisher_id=None, event_type=None,
             # contain confidential information.
             try:
                 return f(self, context, *args, **kw)
-            except Exception, e:
+            except Exception as e:
                 with excutils.save_and_reraise_exception():
                     if notifier:
                         payload = dict(exception=e)

nova/hacking/checks.py

@@ -27,5 +27,29 @@ def import_no_db_in_virt(logical_line, filename):
             yield (0, "N307: nova.db import not allowed in nova/virt/*")
 
 
+def except_python3x_compatible(logical_line, filename):
+    """Check for except statements to be Python 3.x compatible
+
+    As of Python 3.x, the construct "except x,y:" has been removed.
+
+    N308
+    """
+
+    def is_old_style_except(logical_line):
+        # Should match:
+        #     except ProcessExecutionError, exn:
+        # Should not match:
+        #     except UncodeError:
+        #     except (x,y):
+        return (',' in logical_line
+                and ')' not in logical_line.rpartition(',')[2])
+
+    if ("except " in logical_line
+            and logical_line.endswith(':')
+            and is_old_style_except(logical_line)):
+        yield(0, "N308: Python 3.x incompatible 'except x,y:' construct")
+
+
 def factory(register):
     register(import_no_db_in_virt)
+    register(except_python3x_compatible)

nova/image/s3.py

@@ -392,14 +392,14 @@ class S3ImageService(object):
             key = self.cert_rpcapi.decrypt_text(elevated,
                     project_id=context.project_id,
                     text=base64.b64encode(encrypted_key))
-        except Exception, exc:
+        except Exception as exc:
             msg = _('Failed to decrypt private key: %s') % exc
             raise exception.NovaException(msg)
         try:
             iv = self.cert_rpcapi.decrypt_text(elevated,
                     project_id=context.project_id,
                     text=base64.b64encode(encrypted_iv))
-        except Exception, exc:
+        except Exception as exc:
             raise exception.NovaException(_('Failed to decrypt initialization '
                                     'vector: %s') % exc)
 
@@ -410,7 +410,7 @@ class S3ImageService(object):
                           '-K', '%s' % (key,),
                           '-iv', '%s' % (iv,),
                           '-out', '%s' % (decrypted_filename,))
-        except processutils.ProcessExecutionError, exc:
+        except processutils.ProcessExecutionError as exc:
             raise exception.NovaException(_('Failed to decrypt image file '
                                     '%(image_file)s: %(err)s') %
                                     {'image_file': encrypted_filename,

nova/openstack/common/processutils.py

@@ -203,7 +203,7 @@ def trycmd(*args, **kwargs):
     try:
         out, err = execute(*args, **kwargs)
         failed = False
-    except ProcessExecutionError, exn:
+    except ProcessExecutionError as exn:
         out, err = '', str(exn)
         failed = True
 

nova/scheduler/scheduler_options.py

@@ -66,7 +66,7 @@ class SchedulerOptions(object):
         """Get the last modified datetime. Broken out for testing."""
         try:
             return os.path.getmtime(filename)
-        except os.error, e:
+        except os.error as e:
             with excutils.save_and_reraise_exception():
                 LOG.exception(_("Could not stat scheduler options file "
                                 "%(filename)s: '%(e)s'"), locals())
@@ -75,7 +75,7 @@ class SchedulerOptions(object):
         """Decode the JSON file. Broken out for testing."""
         try:
             return json.load(handle)
-        except ValueError, e:
+        except ValueError as e:
             LOG.exception(_("Could not decode scheduler options: "
                             "'%(e)s'") % locals())
             return {}

nova/tests/api/openstack/compute/test_limits.py

@@ -462,7 +462,7 @@ class ParseLimitsTest(BaseLimitTestSuite):
                                             '(PUT, /foo*, /foo.*, 10, hour);'
                                             '(POST, /bar*, /bar.*, 5, second);'
                                             '(Say, /derp*, /derp.*, 1, day)')
-        except ValueError, e:
+        except ValueError as e:
             assert False, str(e)
 
         # Make sure the number of returned limits are correct

nova/tests/test_api.py

@@ -309,7 +309,7 @@ class ApiEc2TestCase(test.TestCase):
 
         try:
             self.ec2.create_key_pair('test')
-        except boto_exc.EC2ResponseError, e:
+        except boto_exc.EC2ResponseError as e:
             if e.code == 'InvalidKeyPair.Duplicate':
                 pass
             else:

nova/tests/test_migrations.py

@@ -219,7 +219,7 @@ class BaseMigrationTestCase(test.TestCase):
                 for key, value in defaults.items():
                     self.test_databases[key] = value
                 self.snake_walk = cp.getboolean('walk_style', 'snake_walk')
-            except ConfigParser.ParsingError, e:
+            except ConfigParser.ParsingError as e:
                 self.fail("Failed to read test_migrations.conf config "
                           "file. Got error: %s" % e)
         else:

nova/tests/test_notifications.py

@@ -99,7 +99,7 @@ class NotificationsTestCase(test.TestCase):
         try:
             # Get a real exception with a call stack.
             raise test.TestingException("junk")
-        except test.TestingException, e:
+        except test.TestingException as e:
             exception = e
 
         notifications.send_api_fault("http://example.com/foo", 500, exception)

nova/tests/virt/libvirt/test_fakelibvirt.py

@@ -136,7 +136,7 @@ class FakeLibvirtTests(test.TestCase):
         conn = self.get_openAuth_curry_func()('qemu:///system')
         try:
             getattr(conn, xmlfunc_name)("this is not valid </xml>", *args)
-        except libvirt.libvirtError, e:
+        except libvirt.libvirtError as e:
             self.assertEqual(e.get_error_code(), libvirt.VIR_ERR_XML_DETAIL)
             self.assertEqual(e.get_error_domain(), libvirt.VIR_FROM_DOMAIN)
             return
@@ -242,7 +242,7 @@ class FakeLibvirtTests(test.TestCase):
         dom_id = conn.listDomainsID()[0]
         try:
             conn.lookupByID(dom_id + 1)
-        except libvirt.libvirtError, e:
+        except libvirt.libvirtError as e:
             self.assertEqual(e.get_error_code(), libvirt.VIR_ERR_NO_DOMAIN)
             self.assertEqual(e.get_error_domain(), libvirt.VIR_FROM_QEMU)
             return
@@ -315,7 +315,7 @@ class FakeLibvirtTests(test.TestCase):
         nwfilter.undefine()
         try:
             conn.nwfilterLookupByName('nova-instance-instance-789320334')
-        except libvirt.libvirtError, e:
+        except libvirt.libvirtError as e:
             self.assertEqual(e.get_error_code(), libvirt.VIR_ERR_NO_NWFILTER)
             self.assertEqual(e.get_error_domain(), libvirt.VIR_FROM_NWFILTER)
             return

nova/tests/virt/libvirt/test_libvirt.py

@@ -2153,7 +2153,7 @@ class LibvirtConnTestCase(test.TestCase):
             conn.ensure_filtering_rules_for_instance(instance_ref,
                                                      network_info,
                                                      time_module=fake_timer)
-        except exception.NovaException, e:
+        except exception.NovaException as e:
             msg = ('The firewall filter for %s does not exist' %
                    instance_ref['name'])
             c1 = (0 <= str(e).find(msg))

nova/utils.py

@@ -927,7 +927,7 @@ def tempdir(**kwargs):
     finally:
         try:
             shutil.rmtree(tmpdir)
-        except OSError, e:
+        except OSError as e:
             LOG.error(_('Could not remove tmpdir: %s'), str(e))
 
 
@@ -1007,7 +1007,7 @@ def last_bytes(file_like_object, num):
 
     try:
         file_like_object.seek(-num, os.SEEK_END)
-    except IOError, e:
+    except IOError as e:
         if e.errno == 22:
             file_like_object.seek(0, os.SEEK_SET)
         else:
@@ -1074,7 +1074,7 @@ class ExceptionHelper(object):
         def wrapper(*args, **kwargs):
             try:
                 return func(*args, **kwargs)
-            except rpc_common.ClientException, e:
+            except rpc_common.ClientException as e:
                 raise (e._exc_info[1], None, e._exc_info[2])
         return wrapper
 

nova/virt/xenapi/vmops.py

@@ -877,7 +877,7 @@ class VMOps(object):
             new_vdi_ref, new_vdi_uuid = create_copy_vdi_and_resize(
                 undo_mgr, old_vdi_ref)
             transfer_vhd_to_dest(new_vdi_ref, new_vdi_uuid)
-        except Exception, error:
+        except Exception as error:
             msg = _("_migrate_disk_resizing_down failed. "
                     "Restoring orig vm due_to: %{exception}.")
             LOG.exception(msg, instance=instance)

smoketests/base.py

@@ -98,7 +98,7 @@ class SmokeTestCase(unittest.TestCase):
             try:
                 conn = self.connect_ssh(ip, key_name)
                 conn.close()
-            except Exception, e:
+            except Exception as e:
                 time.sleep(wait)
             else:
                 return True

tools/conf/extract_opts.py

@@ -104,12 +104,12 @@ def _import_module(mod_str):
             return sys.modules[mod_str[4:]]
         else:
             return importutils.import_module(mod_str)
-    except (ValueError, AttributeError), err:
+    except (ValueError, AttributeError) as err:
         return None
-    except ImportError, ie:
+    except ImportError as ie:
         sys.stderr.write("%s\n" % str(ie))
         return None
-    except Exception, e:
+    except Exception as e:
         return None