96 lines
2.9 KiB
Python
96 lines
2.9 KiB
Python
# -*- coding: utf-8 -*-
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright (C) 2012 Yahoo! Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import abc
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import contextlib
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from oslo.config import cfg
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from nova.openstack.common import importutils
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from nova.openstack.common import log as logging
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LOG = logging.getLogger(__name__)
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jobboard_driver_opt = cfg.StrOpt('job_board_driver',
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default='memory',
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help='The driver that satisfies the '
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'job providing service ( '
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'valid options are: db, mq, zk, memory)')
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CONF = cfg.CONF
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CONF.register_opts([jobboard_driver_opt])
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class API(object):
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_driver = None
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_driver_name_class_mapping = {
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# TBD
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}
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def __new__(cls, *args, **kwargs):
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'''Create an instance of the lock provider API.
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args and kwargs are passed down to the job board driver when it gets
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created.
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'''
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if not cls._driver:
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LOG.debug(_('Job board driver defined as an instance of %s'),
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str(CONF.job_board_driver))
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driver_name = CONF.job_board_driver
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try:
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driver_class = cls._driver_name_class_mapping[driver_name]
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except KeyError:
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raise TypeError(_("Unknown job board driver name: %s")
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% driver_name)
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cls._driver = importutils.import_object(driver_class,
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*args, **kwargs)
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utils.check_isinstance(cls._driver, JobBoardDriver)
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return super(API, cls).__new__(cls)
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class JobBoardDriver(object):
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"""Base class for job board drivers."""
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__metaclass__ = abc.ABCMeta
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def __init__(self):
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self._listeners = []
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@abc.abstractmethod
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def post(self, job):
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raise NotImplementedError()
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def _notify_posted(self, job):
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for i in self._listeners:
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i.notify_posted(job)
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@abc.abstractmethod
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def await(self, blocking=True):
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raise NotImplementedError()
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def subscribe(self, listener):
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self._listeners.append(listener)
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def unsubscribe(self, listener):
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if listener in self._listeners:
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self._listeners.remove(listener)
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def close(self):
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"""Allows the job board provider to free any resources that it has."""
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pass
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