f6b6aafb06
This framework was merged a year ago and AFAICT hasn't seen use beyond the two initial wikimedia extensions. The framework basically allows a way for a single plugin to register API extensions and notification drivers. Both of these can be done by directly using config opts like osapi_compute_extension and notification_driver so this framework really only helps if we expected to (and wanted to) lots of these plugins in the wild. Change-Id: I09a11f9931ee0436a56e8b0d925683b54f73b104
165 lines
6.3 KiB
Python
165 lines
6.3 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
|
|
|
|
# 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 nova import baserpc
|
|
from nova.db import base
|
|
from nova.objects import base as objects_base
|
|
from nova.openstack.common import log as logging
|
|
from nova.openstack.common import periodic_task
|
|
from nova.openstack.common.rpc import dispatcher as rpc_dispatcher
|
|
from nova.scheduler import rpcapi as scheduler_rpcapi
|
|
|
|
|
|
CONF = cfg.CONF
|
|
CONF.import_opt('host', 'nova.netconf')
|
|
LOG = logging.getLogger(__name__)
|
|
|
|
|
|
class Manager(base.Base, periodic_task.PeriodicTasks):
|
|
# Set RPC API version to 1.0 by default.
|
|
RPC_API_VERSION = '1.0'
|
|
|
|
def __init__(self, host=None, db_driver=None, service_name='undefined'):
|
|
if not host:
|
|
host = CONF.host
|
|
self.host = host
|
|
self.backdoor_port = None
|
|
self.service_name = service_name
|
|
super(Manager, self).__init__(db_driver)
|
|
|
|
def create_rpc_dispatcher(self, backdoor_port=None, additional_apis=None):
|
|
'''Get the rpc dispatcher for this manager.
|
|
|
|
If a manager would like to set an rpc API version, or support more than
|
|
one class as the target of rpc messages, override this method.
|
|
'''
|
|
apis = []
|
|
if additional_apis:
|
|
apis.extend(additional_apis)
|
|
base_rpc = baserpc.BaseRPCAPI(self.service_name, backdoor_port)
|
|
apis.extend([self, base_rpc])
|
|
serializer = objects_base.NovaObjectSerializer()
|
|
return rpc_dispatcher.RpcDispatcher(apis, serializer)
|
|
|
|
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)
|
|
|
|
def init_host(self):
|
|
"""Hook to do additional manager initialization when one requests
|
|
the service be started. This is called before any service record
|
|
is created.
|
|
|
|
Child classes should override this method.
|
|
"""
|
|
pass
|
|
|
|
def pre_start_hook(self, **kwargs):
|
|
"""Hook to provide the manager the ability to do additional
|
|
start-up work before any RPC queues/consumers are created. This is
|
|
called after other initialization has succeeded and a service
|
|
record is created.
|
|
|
|
Child classes should override this method.
|
|
"""
|
|
pass
|
|
|
|
def post_start_hook(self):
|
|
"""Hook to provide the manager the ability to do additional
|
|
start-up work immediately after a service creates RPC consumers
|
|
and starts 'running'.
|
|
|
|
Child classes should override this method.
|
|
"""
|
|
pass
|
|
|
|
|
|
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.
|
|
|
|
"""
|
|
|
|
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,
|
|
service_name)
|
|
|
|
def update_service_capabilities(self, capabilities):
|
|
"""Remember these capabilities to send on next periodic update."""
|
|
if not isinstance(capabilities, list):
|
|
capabilities = [capabilities]
|
|
self.last_capabilities = capabilities
|
|
|
|
@periodic_task.periodic_task
|
|
def publish_service_capabilities(self, context):
|
|
"""Pass data back to the scheduler.
|
|
|
|
Called at a periodic interval. And also called via rpc soon after
|
|
the start of the scheduler.
|
|
"""
|
|
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)
|