71478b89ac
Create the basic Service class for binaries running on hosts. A service takes a manager and enables rpc by listening to queues based on topic. It also periodically runs tasks on the manager(optional) and reports it state to the database services table. Also add some unit tests for Service class. Partial-Bug: #1527097 Change-Id: I241c4757d0b2d1880d1a1a59cce007ca9d1037c7
113 lines
3.6 KiB
Python
113 lines
3.6 KiB
Python
# 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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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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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 oslo_log import log as logging
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import oslo_messaging as messaging
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from oslo_service import periodic_task
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from smaug.db import base
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from smaug import version
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CONF = cfg.CONF
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LOG = logging.getLogger(__name__)
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class PeriodicTasks(periodic_task.PeriodicTasks):
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def __init__(self):
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super(PeriodicTasks, self).__init__(CONF)
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class Manager(base.Base, 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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target = messaging.Target(version=RPC_API_VERSION)
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def __init__(self, host=None, db_driver=None):
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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.additional_endpoints = []
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super(Manager, self).__init__(db_driver)
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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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"""Handle initialization if this is a standalone service.
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A hook point for services to execute tasks before the services are made
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available (i.e. showing up on RPC and starting to accept RPC calls) to
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other components. Child classes should override this method.
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"""
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pass
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def init_host_with_rpc(self):
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"""A hook for service to do jobs after RPC is ready.
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Like init_host(), this method is a hook where services get a chance
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to execute tasks that *need* RPC. Child classes should override
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this method.
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"""
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pass
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def service_version(self):
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return version.version_string()
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def service_config(self):
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config = {}
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for key in CONF:
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config[key] = CONF.get(key, None)
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return config
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def is_working(self):
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"""Method indicating if service is working correctly.
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This method is supposed to be overriden by subclasses and return if
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manager is working correctly.
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"""
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return True
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