os-brick/os_brick/executor.py
Gorka Eguileor a9f50dd382 Fix cmd execution stderr, stdout unicode errors
If we run a command that returns non ascii character on stdout or stderr
using _execute attribute from Executor class or any of the inheriting
classes and we try to use stdout or stderr in the logs without decoding
it first, it will results in an exception like:

 UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position
 19: ordinal not in range(128)

In existing code this can happen in quite a lot of places, and not only
where we are logging an error but also when we are logging progress or
debug information.

For example when running dd we could get in stdout:

 1+0 registros leídos
 1+0 registros escritos
 512 bytes (512 B) copiados, 0,000368406 s, 1,4 MB/s

Instead of decoding stdout and stderr whenever we want to use them, this
patch takes another approach, capturing ProcessExecutionError exceptions
and converting string field to unicode and converting returned values of
the execution as well.  That way we can safely use the exception
contents and returned values anywhere in the code.

Closes-Bug: #1602346
Change-Id: I46d8a47ae4f638dbb4b0dc125008bceb0f29fa15
2016-08-25 16:34:28 +00:00

63 lines
2.2 KiB
Python

# (c) Copyright 2013 Hewlett-Packard Development Company, L.P.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""Generic exec utility that allows us to set the
execute and root_helper attributes for putils.
Some projects need their own execute wrapper
and root_helper settings, so this provides that hook.
"""
from oslo_concurrency import processutils as putils
from oslo_utils import encodeutils
from os_brick.privileged import rootwrap as priv_rootwrap
class Executor(object):
def __init__(self, root_helper, execute=None,
*args, **kwargs):
if execute is None:
execute = priv_rootwrap.execute
self.set_execute(execute)
self.set_root_helper(root_helper)
@staticmethod
def safe_decode(string):
return string and encodeutils.safe_decode(string, errors='ignore')
@classmethod
def make_putils_error_safe(cls, exc):
"""Converts ProcessExecutionError string attributes to unicode."""
for field in ('stderr', 'stdout', 'cmd', 'description'):
value = getattr(exc, field, None)
if value:
setattr(exc, field, cls.safe_decode(value))
def _execute(self, *args, **kwargs):
try:
result = self.__execute(*args, **kwargs)
if result:
result = (self.safe_decode(result[0]),
self.safe_decode(result[1]))
return result
except putils.ProcessExecutionError as e:
self.make_putils_error_safe(e)
raise
def set_execute(self, execute):
self.__execute = execute
def set_root_helper(self, helper):
self._root_helper = helper