70f44024f9
Signed-off-by: Kevin Carter <kevin.carter@rackspace.com>
177 lines
5.2 KiB
Python
177 lines
5.2 KiB
Python
# Copyright 2017, Kevin Carter <kevin@cloudnull.com>
|
|
#
|
|
# 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.
|
|
"""Common code for utils."""
|
|
|
|
import functools
|
|
import os
|
|
import sys
|
|
import time
|
|
import traceback
|
|
|
|
try:
|
|
if sys.version_info > (3, 2, 0): # pragma: no cover
|
|
import configparser as ConfigParser
|
|
else: # pragma: no cover
|
|
import ConfigParser
|
|
except ImportError: # pragma: no cover
|
|
raise SystemExit('No configparser module was found.')
|
|
|
|
import diskcache
|
|
|
|
|
|
def retry(ExceptionToCheck, tries=3, delay=1, backoff=1): # noqa
|
|
"""Retry calling the decorated function using an exponential backoff.
|
|
|
|
Attributes to sources of inspiration:
|
|
http://www.saltycrane.com/blog/2009/11/trying-out-retry-decorator-python/
|
|
http://wiki.python.org/moin/PythonDecoratorLibrary#Retry
|
|
|
|
:param ExceptionToCheck: the exception to check. may be a tuple of
|
|
exceptions to check
|
|
:type ExceptionToCheck: Exception or tuple
|
|
:param tries: number of times to try (not retry) before giving up
|
|
:type tries: int
|
|
:param delay: initial delay between retries in seconds
|
|
:type delay: int
|
|
:param backoff: backoff multiplier e.g. value of 2 will double the delay
|
|
each retry
|
|
:type backoff: int
|
|
"""
|
|
def deco_retry(f):
|
|
@functools.wraps(f)
|
|
def f_retry(*args, **kwargs):
|
|
mtries, mdelay = tries, delay
|
|
while mtries > 1:
|
|
try:
|
|
return f(*args, **kwargs)
|
|
except ExceptionToCheck:
|
|
time.sleep(mdelay)
|
|
mtries -= 1
|
|
mdelay *= backoff
|
|
return f(*args, **kwargs)
|
|
return f_retry # true decorator
|
|
return deco_retry
|
|
|
|
|
|
def is_int(value):
|
|
"""Check if a variable is an integer.
|
|
|
|
:param value: parameter to evaluate and return
|
|
:type value: str || int || float
|
|
:returns: str || int || float
|
|
"""
|
|
for v_type in [int, float]:
|
|
try:
|
|
value = v_type(value)
|
|
except ValueError:
|
|
pass # v was not a int, float, or long
|
|
else:
|
|
return value
|
|
else:
|
|
return value
|
|
|
|
|
|
class LocalCache(object):
|
|
"""Context Manager for opening and closing access to the cache objects."""
|
|
|
|
def __init__(self, cache_path=None):
|
|
"""Set the Path cache object.
|
|
|
|
:param cache_file: File path to store cache
|
|
:type cache_file: str
|
|
"""
|
|
# If a cache file is provided use it otherwise store one in
|
|
# the user home folder as a hidden folder.
|
|
self.cache_path = cache_path
|
|
if not self.cache_path:
|
|
self.cache_path = os.path.join(
|
|
os.path.expanduser('~'),
|
|
'.cache/monitorstack.cache'
|
|
)
|
|
elif not self.cache_path.endswith('cache'):
|
|
self.cache_path = '{}.cache'.format(self.cache_path)
|
|
|
|
if not os.path.isdir(self.cache_path):
|
|
os.makedirs(self.cache_path)
|
|
|
|
def __enter__(self):
|
|
"""Open the cache object.
|
|
|
|
:returns: object
|
|
"""
|
|
return self.open_cache
|
|
|
|
def __exit__(self, *args, **kwargs):
|
|
"""Close cache object."""
|
|
self.lc_close()
|
|
|
|
@property
|
|
@retry(ExceptionToCheck=Exception)
|
|
def open_cache(self):
|
|
"""Return open caching opbject.
|
|
|
|
:returns: object
|
|
"""
|
|
return diskcache.Cache(directory=self.cache_path)
|
|
|
|
def lc_open(self):
|
|
"""Open shelved data.
|
|
|
|
:param cache_file: File path to store cache
|
|
:type cache_file: str
|
|
:returns: object
|
|
"""
|
|
return self.open_cache
|
|
|
|
def lc_close(self):
|
|
"""Close shelved data."""
|
|
self.open_cache.close()
|
|
|
|
|
|
def read_config(config_file):
|
|
"""Read an OpenStack configuration.
|
|
|
|
:param config_file: path to configuration file.
|
|
:type config_file: str
|
|
"""
|
|
cfg = os.path.abspath(os.path.expanduser(config_file))
|
|
if not os.path.isfile(cfg):
|
|
raise IOError('Config file "{}" was not found'.format(cfg))
|
|
|
|
parser = ConfigParser.ConfigParser()
|
|
parser.optionxform = str
|
|
parser.read([cfg])
|
|
args = dict()
|
|
defaults = dict([(k, v) for k, v in parser.items(section='DEFAULT')])
|
|
for section in parser.sections():
|
|
sec = args[section] = defaults
|
|
for key, value in parser.items(section):
|
|
sec[key] = is_int(value=value)
|
|
|
|
return args
|
|
|
|
|
|
def log_exception(exp):
|
|
"""Return log entries.
|
|
|
|
:param exp: Exception object or name.
|
|
:type exp: str || object
|
|
:return: str
|
|
"""
|
|
_trace = [i.strip() for i in str(traceback.format_exc()).splitlines()]
|
|
trace = ' -> '.join(_trace)
|
|
_exception = [i.strip() for i in str(exp).splitlines()]
|
|
exception = ' -> '.join(_exception)
|
|
return 'Exception [ %s ]: Trace: [ %s ]' % (exception, trace)
|