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OpenStack Study: service.py**** CubicPower OpenStack Study ****
# Copyright 2010 United States Government as represented by the # Administrator of the National Aeronautics and Space Administration. # Copyright 2011 Justin Santa Barbara # 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. """Generic Node base class for all workers that run on hosts.""" import inspect import os import random from oslo.config import cfg from oslo import messaging from cinder import context from cinder import db from cinder import exception from cinder.openstack.common import importutils from cinder.openstack.common import log as logging from cinder.openstack.common import loopingcall from cinder.openstack.common import service from cinder import rpc from cinder import version from cinder import wsgi LOG = logging.getLogger(__name__) service_opts = [ cfg.IntOpt('report_interval', default=10, help='seconds between nodes reporting state to datastore'), cfg.IntOpt('periodic_interval', default=60, help='seconds between running periodic tasks'), cfg.IntOpt('periodic_fuzzy_delay', default=60, help='range of seconds to randomly delay when starting the' ' periodic task scheduler to reduce stampeding.' ' (Disable by setting to 0)'), cfg.StrOpt('osapi_volume_listen', default="0.0.0.0", help='IP address for OpenStack Volume API to listen'), cfg.IntOpt('osapi_volume_listen_port', default=8776, help='port for os volume api to listen'), cfg.IntOpt('osapi_volume_workers', help='Number of workers for OpenStack Volume API service'), ] CONF = cfg.CONF CONF.register_opts(service_opts)
**** CubicPower OpenStack Study **** class Service(service.Service): """Service object 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 and reports it state to the database services table. """
**** CubicPower OpenStack Study **** def __init__(self, host, binary, topic, manager, report_interval=None, periodic_interval=None, periodic_fuzzy_delay=None, service_name=None, *args, **kwargs): super(Service, self).__init__() if not rpc.initialized(): rpc.init(CONF) self.host = host self.binary = binary self.topic = topic self.manager_class_name = manager manager_class = importutils.import_class(self.manager_class_name) self.manager = manager_class(host=self.host, service_name=service_name, *args, **kwargs) self.report_interval = report_interval self.periodic_interval = periodic_interval self.periodic_fuzzy_delay = periodic_fuzzy_delay self.basic_config_check() self.saved_args, self.saved_kwargs = args, kwargs self.timers = []
**** CubicPower OpenStack Study **** def start(self): version_string = version.version_string() LOG.audit(_('Starting %(topic)s node (version %(version_string)s)'), {'topic': self.topic, 'version_string': version_string}) self.model_disconnected = False self.manager.init_host() ctxt = context.get_admin_context() try: service_ref = db.service_get_by_args(ctxt, self.host, self.binary) self.service_id = service_ref['id'] except exception.NotFound: self._create_service_ref(ctxt) LOG.debug(_("Creating RPC server for service %s") % self.topic) target = messaging.Target(topic=self.topic, server=self.host) endpoints = [self.manager] endpoints.extend(self.manager.additional_endpoints) self.rpcserver = rpc.get_server(target, endpoints) self.rpcserver.start() if self.report_interval: pulse = loopingcall.LoopingCall(self.report_state) pulse.start(interval=self.report_interval, initial_delay=self.report_interval) self.timers.append(pulse) if self.periodic_interval: if self.periodic_fuzzy_delay: initial_delay = random.randint(0, self.periodic_fuzzy_delay) else: initial_delay = None periodic = loopingcall.LoopingCall(self.periodic_tasks) periodic.start(interval=self.periodic_interval, initial_delay=initial_delay) self.timers.append(periodic)
**** CubicPower OpenStack Study **** def basic_config_check(self): """Perform basic config checks before starting service.""" # Make sure report interval is less than service down time if self.report_interval: if CONF.service_down_time <= self.report_interval: new_down_time = int(self.report_interval * 2.5) LOG.warn(_("Report interval must be less than service down " "time. Current config service_down_time: " "%(service_down_time)s, report_interval for this: " "service is: %(report_interval)s. Setting global " "service_down_time to: %(new_down_time)s") % {'service_down_time': CONF.service_down_time, 'report_interval': self.report_interval, 'new_down_time': new_down_time}) CONF.set_override('service_down_time', new_down_time)
**** CubicPower OpenStack Study **** def _create_service_ref(self, context): zone = CONF.storage_availability_zone service_ref = db.service_create(context, {'host': self.host, 'binary': self.binary, 'topic': self.topic, 'report_count': 0, 'availability_zone': zone}) self.service_id = service_ref['id']
**** CubicPower OpenStack Study **** def __getattr__(self, key): manager = self.__dict__.get('manager', None) return getattr(manager, key) @classmethod
**** CubicPower OpenStack Study **** def create(cls, host=None, binary=None, topic=None, manager=None, report_interval=None, periodic_interval=None, periodic_fuzzy_delay=None, service_name=None): """Instantiates class and passes back application object. :param host: defaults to CONF.host :param binary: defaults to basename of executable :param topic: defaults to bin_name - 'cinder-' part :param manager: defaults to CONF. :param report_interval: defaults to CONF.report_interval :param periodic_interval: defaults to CONF.periodic_interval :param periodic_fuzzy_delay: defaults to CONF.periodic_fuzzy_delay """ if not host: host = CONF.host if not binary: binary = os.path.basename(inspect.stack()[-1][1]) if not topic: topic = binary if not manager: subtopic = topic.rpartition('cinder-')[2] manager = CONF.get('%s_manager' % subtopic, None) if report_interval is None: report_interval = CONF.report_interval if periodic_interval is None: periodic_interval = CONF.periodic_interval if periodic_fuzzy_delay is None: periodic_fuzzy_delay = CONF.periodic_fuzzy_delay service_obj = cls(host, binary, topic, manager, report_interval=report_interval, periodic_interval=periodic_interval, periodic_fuzzy_delay=periodic_fuzzy_delay, service_name=service_name) return service_obj
**** CubicPower OpenStack Study **** def kill(self): """Destroy the service object in the datastore.""" self.stop() try: db.service_destroy(context.get_admin_context(), self.service_id) except exception.NotFound: LOG.warn(_('Service killed that has no database entry'))
**** CubicPower OpenStack Study **** def stop(self): # Try to shut the connection down, but if we get any sort of # errors, go ahead and ignore them.. as we're shutting down anyway try: self.rpcserver.stop() except Exception: pass for x in self.timers: try: x.stop() except Exception: pass self.timers = [] super(Service, self).stop()
**** CubicPower OpenStack Study **** def wait(self): for x in self.timers: try: x.wait() except Exception: pass
**** CubicPower OpenStack Study **** def periodic_tasks(self, raise_on_error=False): """Tasks to be run at a periodic interval.""" ctxt = context.get_admin_context() self.manager.periodic_tasks(ctxt, raise_on_error=raise_on_error)
**** CubicPower OpenStack Study **** def report_state(self): """Update the state of this service in the datastore.""" ctxt = context.get_admin_context() zone = CONF.storage_availability_zone state_catalog = {} try: try: service_ref = db.service_get(ctxt, self.service_id) except exception.NotFound: LOG.debug(_('The service database object disappeared, ' 'Recreating it.')) self._create_service_ref(ctxt) service_ref = db.service_get(ctxt, self.service_id) state_catalog['report_count'] = service_ref['report_count'] + 1 if zone != service_ref['availability_zone']: state_catalog['availability_zone'] = zone db.service_update(ctxt, self.service_id, state_catalog) # TODO(termie): make this pattern be more elegant. if getattr(self, 'model_disconnected', False): self.model_disconnected = False LOG.error(_('Recovered model server connection!')) # TODO(vish): this should probably only catch connection errors except Exception: # pylint: disable=W0702 if not getattr(self, 'model_disconnected', False): self.model_disconnected = True LOG.exception(_('model server went away'))
**** CubicPower OpenStack Study **** class WSGIService(object): """Provides ability to launch API from a 'paste' configuration."""
**** CubicPower OpenStack Study **** def __init__(self, name, loader=None): """Initialize, but do not start the WSGI server. :param name: The name of the WSGI server given to the loader. :param loader: Loads the WSGI application using the given name. :returns: None """ self.name = name self.manager = self._get_manager() self.loader = loader or wsgi.Loader() self.app = self.loader.load_app(name) self.host = getattr(CONF, '%s_listen' % name, "0.0.0.0") self.port = getattr(CONF, '%s_listen_port' % name, 0) self.workers = getattr(CONF, '%s_workers' % name, None) if self.workers < 1: LOG.warn(_("Value of config option %(name)s_workers must be " "integer greater than 1. Input value ignored.") % {'name': name}) # Reset workers to default self.workers = None self.server = wsgi.Server(name, self.app, host=self.host, port=self.port)
**** CubicPower OpenStack Study **** def _get_manager(self): """Initialize a Manager object appropriate for this service. Use the service name to look up a Manager subclass from the configuration and initialize an instance. If no class name is configured, just return None. :returns: a Manager instance, or None. """ fl = '%s_manager' % self.name if fl not in CONF: return None manager_class_name = CONF.get(fl, None) if not manager_class_name: return None manager_class = importutils.import_class(manager_class_name) return manager_class()
**** CubicPower OpenStack Study **** def start(self): """Start serving this service using loaded configuration. Also, retrieve updated port number in case '0' was passed in, which indicates a random port should be used. :returns: None """ if self.manager: self.manager.init_host() self.server.start() self.port = self.server.port
**** CubicPower OpenStack Study **** def stop(self): """Stop serving this API. :returns: None """ self.server.stop()
**** CubicPower OpenStack Study **** def wait(self): """Wait for the service to stop serving this API. :returns: None """ self.server.wait() def process_launcher(): return service.ProcessLauncher() # NOTE(vish): the global launcher is to maintain the existing # functionality of calling service.serve + # service.wait _launcher = None def serve(server, workers=None): global _launcher if _launcher: raise RuntimeError(_('serve() can only be called once')) _launcher = service.launch(server, workers=workers) def wait(): LOG.debug(_('Full set of CONF:')) for flag in CONF: flag_get = CONF.get(flag, None) # hide flag contents from log if contains a password # should use secret flag when switch over to openstack-common if ("_password" in flag or "_key" in flag or (flag == "sql_connection" and ("mysql:" in flag_get or "postgresql:" in flag_get))): LOG.debug(_('%s : FLAG SET ') % flag) else: LOG.debug('%(flag)s : %(flag_get)s' % {'flag': flag, 'flag_get': flag_get}) try: _launcher.wait() except KeyboardInterrupt: _launcher.stop() rpc.cleanup()
**** CubicPower OpenStack Study **** def process_launcher(): return service.ProcessLauncher() # NOTE(vish): the global launcher is to maintain the existing # functionality of calling service.serve + # service.wait _launcher = None
**** CubicPower OpenStack Study **** def serve(server, workers=None): global _launcher if _launcher: raise RuntimeError(_('serve() can only be called once')) _launcher = service.launch(server, workers=workers)
**** CubicPower OpenStack Study **** def wait(): LOG.debug(_('Full set of CONF:')) for flag in CONF: flag_get = CONF.get(flag, None) # hide flag contents from log if contains a password # should use secret flag when switch over to openstack-common if ("_password" in flag or "_key" in flag or (flag == "sql_connection" and ("mysql:" in flag_get or "postgresql:" in flag_get))): LOG.debug(_('%s : FLAG SET ') % flag) else: LOG.debug('%(flag)s : %(flag_get)s' % {'flag': flag, 'flag_get': flag_get}) try: _launcher.wait() except KeyboardInterrupt: _launcher.stop() rpc.cleanup()
**** CubicPower OpenStack Study **** class Launcher(object):
**** CubicPower OpenStack Study **** def __init__(self): self.launch_service = serve self.wait = wait def get_launcher(): # Note(lpetrut): ProcessLauncher uses green pipes which fail on Windows # due to missing support of non-blocking I/O pipes. For this reason, the # service must be spawned differently on Windows, using the ServiceLauncher # class instead. if os.name == 'nt': return Launcher() else: return process_launcher()
**** CubicPower OpenStack Study **** def get_launcher(): # Note(lpetrut): ProcessLauncher uses green pipes which fail on Windows # due to missing support of non-blocking I/O pipes. For this reason, the # service must be spawned differently on Windows, using the ServiceLauncher # class instead. if os.name == 'nt': return Launcher() else: return process_launcher()
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