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OpenStack Study: manager.py**** CubicPower OpenStack Study ****
# Copyright 2010 United States Government as represented by the # Administrator of the National Aeronautics and Space Administration. # 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. """Base Manager class. Managers are responsible for a certain aspect of the system. It is a logical grouping of code relating to a portion of the system. In general other components should be using the manager to make changes to the components that it is responsible for. For example, other components that need to deal with volumes in some way, should do so by calling methods on the VolumeManager instead of directly changing fields in the database. This allows us to keep all of the code relating to volumes in the same place. We have adopted a basic strategy of Smart managers and dumb data, which means rather than attaching methods to data objects, components should call manager methods that act on the data. Methods on managers that can be executed locally should be called directly. If a particular method must execute on a remote host, this should be done via rpc to the service that wraps the manager Managers should be responsible for most of the db access, and non-implementation specific data. Anything implementation specific that can't be generalized should be done by the Driver. In general, we prefer to have one manager with multiple drivers for different implementations, but sometimes it makes sense to have multiple managers. You can think of it this way: Abstract different overall strategies at the manager level(FlatNetwork vs VlanNetwork), and different implementations at the driver level(LinuxNetDriver vs CiscoNetDriver). Managers will often provide methods for initial setup of a host or periodic tasks to a wrapping service. This module provides Manager, a base class for managers. """ from oslo.config import cfg from oslo import messaging from cinder.db import base from cinder.openstack.common import log as logging from cinder.openstack.common import periodic_task from cinder.scheduler import rpcapi as scheduler_rpcapi from cinder import version CONF = cfg.CONF LOG = logging.getLogger(__name__)
**** CubicPower OpenStack Study **** class Manager(base.Base, periodic_task.PeriodicTasks): # Set RPC API version to 1.0 by
**** CubicPower OpenStack Study **** def __init__(self, host=None, db_driver=None): if not host: host = CONF.host self.host = host self.additional_endpoints = [] super(Manager, self).__init__(db_driver)
**** CubicPower OpenStack Study **** def periodic_tasks(self, context, raise_on_error=False): """Tasks to be run at a periodic interval.""" return self.run_periodic_tasks(context, raise_on_error=raise_on_error)
**** CubicPower OpenStack Study **** def init_host(self): """Handle initialization if this is a standalone service. Child classes should override this method. """ pass
**** CubicPower OpenStack Study **** def service_version(self, context): return version.version_string()
**** CubicPower OpenStack Study **** def service_config(self, context): config = {} for key in CONF: config[key] = CONF.get(key, None) return config
**** CubicPower OpenStack Study **** class SchedulerDependentManager(Manager): """Periodically send capability updates to the Scheduler services. Services that need to update the Scheduler of their capabilities should derive from this class. Otherwise they can derive from manager.Manager directly. Updates are only sent after update_service_capabilities is called with non-None values. """
**** CubicPower OpenStack Study **** def __init__(self, host=None, db_driver=None, service_name='undefined'): self.last_capabilities = None self.service_name = service_name self.scheduler_rpcapi = scheduler_rpcapi.SchedulerAPI() super(SchedulerDependentManager, self).__init__(host, db_driver)
**** CubicPower OpenStack Study **** def update_service_capabilities(self, capabilities): """Remember these capabilities to send on next periodic update.""" self.last_capabilities = capabilities @periodic_task.periodic_task
**** CubicPower OpenStack Study **** def _publish_service_capabilities(self, context): """Pass data back to the scheduler at a periodic interval.""" if self.last_capabilities: LOG.debug(_('Notifying Schedulers of capabilities ...')) self.scheduler_rpcapi.update_service_capabilities( context, self.service_name, self.host, self.last_capabilities)
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