TypeError when logging device_map

[Avishay Traeger]

At the end of _get_connection_devices(), the device_map is logged. This results in the attached stack trace.

If I change the line from:
LOG.debug('Resulting device map %s', device_map)
To:
LOG.debug('Resulting device map %s', str(device_map))
The following is printed:
Resulting device map defaultdict(<function <lambda> at 0x3d99668>, {(u'10.47.212.21:3260', u'iqn.2010-06.com.purestorage:flasharray.5f252660cfa07c08'): (set([u'sdg']), set([])), (u'10.47.212.22:3260', u'iqn.2010-06.com.purestorage:flasharray.5f252660cfa07c08'): (set([u'sdf']), set([])), (u'10.47.212.11:3260', u'iqn.2010-06.com.purestorage:flasharray.5f252660cfa07c08'): (set([u'sdd']), set([])), (u'10.47.212.12:3260', u'iqn.2010-06.com.purestorage:flasharray.5f252660cfa07c08'): (set([u'sde']), set([]))})(iscsi::_get_connection_devices:823)

Traceback (most recent call last):
  File "/usr/lib64/python2.7/logging/__init__.py", line 851, in emit
    msg = self.format(record)
  File "/usr/lib64/python2.7/logging/__init__.py", line 724, in format
    return fmt.format(record)
  File "/usr/lib/python2.7/site-packages/strato_common/log/machinereadableformatter.py", line 12, in format
    return simplejson.dumps(data, default=self._defaultSerializer, encoding='raw-unicode-escape')
  File "/usr/lib64/python2.7/site-packages/simplejson/__init__.py", line 397, in dumps
    **kw).encode(obj)
  File "/usr/lib64/python2.7/site-packages/simplejson/encoder.py", line 275, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/lib64/python2.7/site-packages/simplejson/encoder.py", line 357, in iterencode
    return _iterencode(o, 0)
TypeError: keys must be a string
Logged from file iscsi.py, line 823

[Avishay Traeger (avishay-il)]

Not reproducible