60a91f475a
Add a temporary nova.notifier.Notifier helper class which translates oslo.messaging.Notifier compatible calls into openstack.common.notifier compatible calls. This allows us to port the notifier code over to the oslo.messaging API before actually switching over oslo.messaging fully. This patch contains no functional changes at all, except that all notifications go through this temporary helper class. Some notes on the new API: * The notifier API is changed so that what was previously global state is now encapsulated in a Notifier object. This object also includes the publisher_id and has error()/info()/etc. methods rather than just notify(). * The notify_decorator() helper wasn't carried across to the new API because its semantics are a bit weird. Something along these lines could be added in future, though. * We use a fake Notifier implementation for tests because there's no API in oslo.messaging to actually get the notifications queued up in the fake notification driver, which is a bit dumb. However, this feels like the right thing to do anyway. We're not wanting to test oslo.messaging.Notifier itself, but rather we want to test how we call it. blueprint: oslo-messaging Change-Id: I262163c7e05e6a6fb79265e904ce761fc3ac5806
169 lines
6.5 KiB
Python
169 lines
6.5 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2010 United States Government as represented by the
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# Administrator of the National Aeronautics and Space Administration.
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# 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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"""Base Manager class.
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Managers are responsible for a certain aspect of the system. It is a logical
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grouping of code relating to a portion of the system. In general other
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components should be using the manager to make changes to the components that
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it is responsible for.
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For example, other components that need to deal with volumes in some way,
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should do so by calling methods on the VolumeManager instead of directly
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changing fields in the database. This allows us to keep all of the code
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relating to volumes in the same place.
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We have adopted a basic strategy of Smart managers and dumb data, which means
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rather than attaching methods to data objects, components should call manager
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methods that act on the data.
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Methods on managers that can be executed locally should be called directly. If
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a particular method must execute on a remote host, this should be done via rpc
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to the service that wraps the manager
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Managers should be responsible for most of the db access, and
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non-implementation specific data. Anything implementation specific that can't
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be generalized should be done by the Driver.
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In general, we prefer to have one manager with multiple drivers for different
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implementations, but sometimes it makes sense to have multiple managers. You
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can think of it this way: Abstract different overall strategies at the manager
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level(FlatNetwork vs VlanNetwork), and different implementations at the driver
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level(LinuxNetDriver vs CiscoNetDriver).
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Managers will often provide methods for initial setup of a host or periodic
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tasks to a wrapping service.
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This module provides Manager, a base class for managers.
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"""
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from oslo.config import cfg
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from nova import baserpc
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from nova.db import base
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from nova import notifier
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from nova.objects import base as objects_base
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from nova.openstack.common.gettextutils import _
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from nova.openstack.common import log as logging
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from nova.openstack.common import periodic_task
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from nova.openstack.common.rpc import dispatcher as rpc_dispatcher
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from nova.scheduler import rpcapi as scheduler_rpcapi
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CONF = cfg.CONF
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CONF.import_opt('host', 'nova.netconf')
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LOG = logging.getLogger(__name__)
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class Manager(base.Base, periodic_task.PeriodicTasks):
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# Set RPC API version to 1.0 by default.
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RPC_API_VERSION = '1.0'
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def __init__(self, host=None, db_driver=None, service_name='undefined'):
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if not host:
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host = CONF.host
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self.host = host
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self.backdoor_port = None
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self.service_name = service_name
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self.notifier = notifier.get_notifier(self.service_name, self.host)
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super(Manager, self).__init__(db_driver)
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def create_rpc_dispatcher(self, backdoor_port=None, additional_apis=None):
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'''Get the rpc dispatcher for this manager.
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If a manager would like to set an rpc API version, or support more than
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one class as the target of rpc messages, override this method.
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'''
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apis = []
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if additional_apis:
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apis.extend(additional_apis)
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base_rpc = baserpc.BaseRPCAPI(self.service_name, backdoor_port)
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apis.extend([self, base_rpc])
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serializer = objects_base.NovaObjectSerializer()
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return rpc_dispatcher.RpcDispatcher(apis, serializer)
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def periodic_tasks(self, context, raise_on_error=False):
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"""Tasks to be run at a periodic interval."""
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return self.run_periodic_tasks(context, raise_on_error=raise_on_error)
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def init_host(self):
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"""Hook to do additional manager initialization when one requests
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the service be started. This is called before any service record
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is created.
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Child classes should override this method.
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"""
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pass
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def pre_start_hook(self):
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"""Hook to provide the manager the ability to do additional
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start-up work before any RPC queues/consumers are created. This is
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called after other initialization has succeeded and a service
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record is created.
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Child classes should override this method.
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"""
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pass
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def post_start_hook(self):
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"""Hook to provide the manager the ability to do additional
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start-up work immediately after a service creates RPC consumers
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and starts 'running'.
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Child classes should override this method.
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"""
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pass
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class SchedulerDependentManager(Manager):
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"""Periodically send capability updates to the Scheduler services.
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Services that need to update the Scheduler of their capabilities
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should derive from this class. Otherwise they can derive from
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manager.Manager directly. Updates are only sent after
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update_service_capabilities is called with non-None values.
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"""
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def __init__(self, host=None, db_driver=None, service_name='undefined'):
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self.last_capabilities = None
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self.service_name = service_name
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self.scheduler_rpcapi = scheduler_rpcapi.SchedulerAPI()
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super(SchedulerDependentManager, self).__init__(host, db_driver,
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service_name)
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def update_service_capabilities(self, capabilities):
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"""Remember these capabilities to send on next periodic update."""
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if not isinstance(capabilities, list):
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capabilities = [capabilities]
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self.last_capabilities = capabilities
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def publish_service_capabilities(self, context):
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"""Pass data back to the scheduler.
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Called at a periodic interval. And also called via rpc soon after
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the start of the scheduler.
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"""
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#NOTE(jogo): this is now deprecated, unused and can be removed in
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#V3.0 of compute RPCAPI
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if self.last_capabilities:
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LOG.debug(_('Notifying Schedulers of capabilities ...'))
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self.scheduler_rpcapi.update_service_capabilities(context,
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self.service_name, self.host, self.last_capabilities)
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