ec2-api/ec2api/utils.py

81 lines
2.2 KiB
Python

# Copyright 2014
# The Cloudscaling Group, Inc.
#
# 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.
"""Utilities and helper functions."""
import contextlib
import hashlib
import hmac
import shutil
import tempfile
from xml.sax import saxutils
from oslo_config import cfg
from oslo_log import log as logging
utils_opts = [
cfg.StrOpt('tempdir',
help='Explicitly specify the temporary working directory'),
]
CONF = cfg.CONF
CONF.register_opts(utils_opts)
LOG = logging.getLogger(__name__)
@contextlib.contextmanager
def tempdir(**kwargs):
argdict = kwargs.copy()
if 'dir' not in argdict:
argdict['dir'] = CONF.tempdir
tmpdir = tempfile.mkdtemp(**argdict)
try:
yield tmpdir
finally:
try:
shutil.rmtree(tmpdir)
except OSError as e:
LOG.error('Could not remove tmpdir: %s', str(e))
def get_hash_str(base_str):
"""returns string that represents hash of base_str (in hex format)."""
return hashlib.md5(base_str).hexdigest()
if hasattr(hmac, 'compare_digest'):
constant_time_compare = hmac.compare_digest
else:
def constant_time_compare(first, second):
"""Returns True if both string inputs are equal, otherwise False.
This function should take a constant amount of time regardless of
how many characters in the strings match.
"""
if len(first) != len(second):
return False
result = 0
for x, y in zip(first, second):
result |= ord(x) ^ ord(y)
return result == 0
def xhtml_escape(value):
"""Escapes a string so it is valid within XML or XHTML.
"""
return saxutils.escape(value, {'"': '"', "'": '''})