deb-manila/manila/scheduler/scheduler_options.py
Valeriy Ponomaryov 63a0504c21 Use oslo_log lib
Module 'log' from oslo-incubator was removed after release of oslo_log library.
So, start using oslo_log, but keep oslo-incubator code yet other common modules
within Manila codebase use it.

Implements bp use-oslo-log-lib

Change-Id: I88224f7c2bd99adb78140dfc3fa73cea437f29cd
2015-02-08 10:42:40 +00:00

106 lines
3.5 KiB
Python

# Copyright (c) 2011 OpenStack, LLC.
# All Rights Reserved.
#
# 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.
"""
SchedulerOptions monitors a local .json file for changes and loads
it if needed. This file is converted to a data structure and passed
into the filtering and weighing functions which can use it for
dynamic configuration.
"""
import datetime
import os
from oslo_config import cfg
from oslo_log import log
from oslo_serialization import jsonutils
from oslo_utils import timeutils
from manila.i18n import _LE
scheduler_json_config_location_opt = cfg.StrOpt(
'scheduler_json_config_location',
default='',
help='Absolute path to scheduler configuration JSON file.')
CONF = cfg.CONF
CONF.register_opt(scheduler_json_config_location_opt)
LOG = log.getLogger(__name__)
class SchedulerOptions(object):
"""Monitor and load local .json file for filtering and weighing.
SchedulerOptions monitors a local .json file for changes and loads it
if needed. This file is converted to a data structure and passed into
the filtering and weighing functions which can use it for dynamic
configuration.
"""
def __init__(self):
super(SchedulerOptions, self).__init__()
self.data = {}
self.last_modified = None
self.last_checked = None
def _get_file_handle(self, filename):
"""Get file handle. Broken out for testing."""
return open(filename)
def _get_file_timestamp(self, filename):
"""Get the last modified datetime. Broken out for testing."""
try:
return os.path.getmtime(filename)
except os.error as e:
LOG.exception(_LE("Could not stat scheduler options file "
"%(filename)s: '%(e)s'"),
{"filename": filename, "e": e})
raise
def _load_file(self, handle):
"""Decode the JSON file. Broken out for testing."""
try:
return jsonutils.load(handle)
except ValueError as e:
LOG.exception(_LE("Could not decode scheduler options: "
"'%(e)s'"), {"e": e})
return {}
def _get_time_now(self):
"""Get current UTC. Broken out for testing."""
return timeutils.utcnow()
def get_configuration(self, filename=None):
"""Check the json file for changes and load it if needed."""
if not filename:
filename = CONF.scheduler_json_config_location
if not filename:
return self.data
if self.last_checked:
now = self._get_time_now()
if now - self.last_checked < datetime.timedelta(minutes=5):
return self.data
last_modified = self._get_file_timestamp(filename)
if (not last_modified or not self.last_modified or
last_modified > self.last_modified):
self.data = self._load_file(self._get_file_handle(filename))
self.last_modified = last_modified
if not self.data:
self.data = {}
return self.data