serialize_args throws UnicodeError when message contains non-ascii characters

[Matt Rabe]

The EventReporter attempts to serialize exception messages and raises another error in doing so if the message contains non-ascii characters, masking the original exception.

   File "/usr/lib/python2.7/dist-packages/nova/exception.py", line 89, in wrapped
     payload)
   File "/usr/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 119, in __exit__
     six.reraise(self.type_, self.value, self.tb)
   File "/usr/lib/python2.7/dist-packages/nova/exception.py", line 72, in wrapped
     return f(self, context, *args, **kw)
   File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 349, in decorated_function
     LOG.warning(msg, e, instance_uuid=instance_uuid)
   File "/usr/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 119, in __exit__
     six.reraise(self.type_, self.value, self.tb)
   File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 320, in decorated_function
     return function(self, context, *args, **kwargs)
   File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 399, in decorated_function
     return function(self, context, *args, **kwargs)
   File "/usr/lib/python2.7/dist-packages/nova/compute/utils.py", line 492, in __exit__
     exc_tb=exc_tb, want_result=False)
   File "/usr/lib/python2.7/dist-packages/nova/objects/base.py", line 487, in wrapper
     kwargs[k] = str(v)
   File "/usr/lib/python2.7/dist-packages/oslo_i18n/_message.py", line 167, in __str__
     raise UnicodeError(msg)
 UnicodeError: Message objects do not support str() because they may contain non-ascii characters. Please use unicode() or translate() instead.

Found in Liberty

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/221905

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/221905
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=c4d30dbdc50309c5f95eb630840c3c32b4e96c8f
Submitter: Jenkins
Branch: master

commit c4d30dbdc50309c5f95eb630840c3c32b4e96c8f
Author: Matt Rabe <email address hidden>
Date: Wed Sep 9 20:29:57 2015 +0200

    Use six.text_type instead of str in serialize_args

    The EventReporter serializes any exception messages in
    the event of a failure. If the message contains non-ascii
    characters the string translation throws another exception
    masking the original.

    Change-Id: I13d277b803bcbcf010d42bbebe7eea61642be21a
    Closes-Bug: #1493947