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OpenStack Study: api.py**** CubicPower OpenStack Study ****
# Copyright (c) AT&T Labs Inc. 2012 Yun Mao # # 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. """Define APIs for the servicegroup access.""" import random from oslo.config import cfg from nova.openstack.common.gettextutils import _ from nova.openstack.common import importutils from nova.openstack.common import log as logging from nova import utils LOG = logging.getLogger(__name__) _default_driver = 'db' servicegroup_driver_opt = cfg.StrOpt('servicegroup_driver', default=_default_driver, help='The driver for servicegroup ' 'service (valid options are: ' 'db, zk, mc)') CONF = cfg.CONF CONF.register_opt(servicegroup_driver_opt) # NOTE(geekinutah): By default drivers wait 5 seconds before reporting INITIAL_REPORTING_DELAY = 5
**** CubicPower OpenStack Study **** class API(object): _driver = None _driver_name_class_mapping = { 'db': 'nova.servicegroup.drivers.db.DbDriver', 'zk': 'nova.servicegroup.drivers.zk.ZooKeeperDriver', 'mc': 'nova.servicegroup.drivers.mc.MemcachedDriver' }
**** CubicPower OpenStack Study **** def __new__(cls, *args, **kwargs): '''Create an instance of the servicegroup API. args and kwargs are passed down to the servicegroup driver when it gets created. No args currently exist, though. Valid kwargs are: db_allowed - Boolean. False if direct db access is not allowed and alternative data access (conductor) should be used instead. ''' if not cls._driver: LOG.debug(_('ServiceGroup driver defined as an instance of %s'), str(CONF.servicegroup_driver)) driver_name = CONF.servicegroup_driver try: driver_class = cls._driver_name_class_mapping[driver_name] except KeyError: raise TypeError(_("unknown ServiceGroup driver name: %s") % driver_name) cls._driver = importutils.import_object(driver_class, *args, **kwargs) utils.check_isinstance(cls._driver, ServiceGroupDriver) # we don't have to check that cls._driver is not NONE, # check_isinstance does it return super(API, cls).__new__(cls)
**** CubicPower OpenStack Study **** def __init__(self, *args, **kwargs): self.basic_config_check()
**** CubicPower OpenStack Study **** def basic_config_check(self): """Perform basic config check.""" # Make sure report interval is less than service down time report_interval = CONF.report_interval if CONF.service_down_time <= report_interval: new_service_down_time = int(report_interval * 2.5) LOG.warn(_("Report interval must be less than service down " "time. Current config: "%(report_interval)s>. Setting service_down_time to: " "%(new_service_down_time)s"), {'service_down_time': CONF.service_down_time, 'report_interval': report_interval, 'new_service_down_time': new_service_down_time}) CONF.set_override('service_down_time', new_service_down_time)
**** CubicPower OpenStack Study **** def join(self, member_id, group_id, service=None): """Add a new member to the ServiceGroup @param member_id: the joined member ID @param group_id: the group name, of the joined member @param service: the parameter can be used for notifications about disconnect mode and update some internals """ msg = _('Join new ServiceGroup member %(member_id)s to the ' '%(group_id)s group, service = %(service)s') LOG.debug(msg, {'member_id': member_id, 'group_id': group_id, 'service': service}) return self._driver.join(member_id, group_id, service)
**** CubicPower OpenStack Study **** def service_is_up(self, member): """Check if the given member is up.""" msg = _('Check if the given member [%s] is part of the ' 'ServiceGroup, is up') LOG.debug(msg, member) return self._driver.is_up(member)
**** CubicPower OpenStack Study **** def leave(self, member_id, group_id): """Explicitly remove the given member from the ServiceGroup monitoring. """ msg = _('Explicitly remove the given member %(member_id)s from the' '%(group_id)s group monitoring') LOG.debug(msg, {'member_id': member_id, 'group_id': group_id}) return self._driver.leave(member_id, group_id)
**** CubicPower OpenStack Study **** def get_all(self, group_id): """Returns ALL members of the given group.""" LOG.debug(_('Returns ALL members of the [%s] ' 'ServiceGroup'), group_id) return self._driver.get_all(group_id)
**** CubicPower OpenStack Study **** def get_one(self, group_id): """Returns one member of the given group. The strategy to select the member is decided by the driver (e.g. random or round-robin). """ LOG.debug(_('Returns one member of the [%s] group'), group_id) return self._driver.get_one(group_id)
**** CubicPower OpenStack Study **** class ServiceGroupDriver(object): """Base class for ServiceGroup drivers."""
**** CubicPower OpenStack Study **** def join(self, member_id, group_id, service=None): """Join the given service with it's group.""" raise NotImplementedError()
**** CubicPower OpenStack Study **** def is_up(self, member): """Check whether the given member is up.""" raise NotImplementedError()
**** CubicPower OpenStack Study **** def leave(self, member_id, group_id): """Remove the given member from the ServiceGroup monitoring.""" raise NotImplementedError()
**** CubicPower OpenStack Study **** def get_all(self, group_id): """Returns ALL members of the given group.""" raise NotImplementedError()
**** CubicPower OpenStack Study **** def get_one(self, group_id): """The default behavior of get_one is to randomly pick one from the result of get_all(). This is likely to be overridden in the actual driver implementation. """ members = self.get_all(group_id) if members is None: return None length = len(members) if length == 0: return None return random.choice(members)
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