# Copyright (c) 2012 OpenStack Foundation. # Copyright (c) 2014 Red Hat, Inc. # 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. import collections import random import time from neutron_lib import context from neutron_lib import exceptions as lib_exceptions from oslo_config import cfg from oslo_log import log as logging import oslo_messaging from oslo_messaging.rpc import dispatcher from oslo_messaging import serializer as om_serializer from oslo_service import service from oslo_utils import excutils from osprofiler import profiler from neutron.common import exceptions LOG = logging.getLogger(__name__) TRANSPORT = None NOTIFICATION_TRANSPORT = None NOTIFIER = None ALLOWED_EXMODS = [ exceptions.__name__, lib_exceptions.__name__, ] EXTRA_EXMODS = [] # NOTE(salv-orlando): I am afraid this is a global variable. While not ideal, # they're however widely used throughout the code base. It should be set to # true if the RPC server is not running in the current process space. This # will prevent get_connection from creating connections to the AMQP server RPC_DISABLED = False def init(conf): global TRANSPORT, NOTIFICATION_TRANSPORT, NOTIFIER exmods = get_allowed_exmods() TRANSPORT = oslo_messaging.get_rpc_transport(conf, allowed_remote_exmods=exmods) NOTIFICATION_TRANSPORT = oslo_messaging.get_notification_transport( conf, allowed_remote_exmods=exmods) serializer = RequestContextSerializer() NOTIFIER = oslo_messaging.Notifier(NOTIFICATION_TRANSPORT, serializer=serializer) def cleanup(): global TRANSPORT, NOTIFICATION_TRANSPORT, NOTIFIER assert TRANSPORT is not None assert NOTIFICATION_TRANSPORT is not None assert NOTIFIER is not None TRANSPORT.cleanup() NOTIFICATION_TRANSPORT.cleanup() _BackingOffContextWrapper.reset_timeouts() TRANSPORT = NOTIFICATION_TRANSPORT = NOTIFIER = None def add_extra_exmods(*args): EXTRA_EXMODS.extend(args) def clear_extra_exmods(): del EXTRA_EXMODS[:] def get_allowed_exmods(): return ALLOWED_EXMODS + EXTRA_EXMODS def _get_default_method_timeout(): return TRANSPORT.conf.rpc_response_timeout def _get_default_method_timeouts(): return collections.defaultdict(_get_default_method_timeout) class _ContextWrapper(object): def __init__(self, original_context): self._original_context = original_context def __getattr__(self, name): return getattr(self._original_context, name) def cast(self, ctxt, method, **kwargs): try: self._original_context.cast(ctxt, method, **kwargs) except Exception as e: # TODO(kevinbenton): make catch specific to missing exchange once # bug/1705351 is resolved on the oslo.messaging side; if # oslo.messaging auto-creates the exchange, then just remove the # code completely LOG.debug("Ignored exception during cast: %e", e) class _BackingOffContextWrapper(_ContextWrapper): """Wraps oslo messaging contexts to set the timeout for calls. This intercepts RPC calls and sets the timeout value to the globally adapting value for each method. An oslo messaging timeout results in a doubling of the timeout value for the method on which it timed out. There currently is no logic to reduce the timeout since busy Neutron servers are more frequently the cause of timeouts rather than lost messages. """ _METHOD_TIMEOUTS = _get_default_method_timeouts() _max_timeout = None @classmethod def reset_timeouts(cls): # restore the original default timeout factory cls._METHOD_TIMEOUTS = _get_default_method_timeouts() cls._max_timeout = None @classmethod def get_max_timeout(cls): return cls._max_timeout or _get_default_method_timeout() * 10 @classmethod def set_max_timeout(cls, max_timeout): if max_timeout < cls.get_max_timeout(): cls._METHOD_TIMEOUTS = collections.defaultdict( lambda: max_timeout, **{ k: min(v, max_timeout) for k, v in cls._METHOD_TIMEOUTS.items() }) cls._max_timeout = max_timeout def call(self, ctxt, method, **kwargs): # two methods with the same name in different namespaces should # be tracked independently if self._original_context.target.namespace: scoped_method = '%s.%s' % (self._original_context.target.namespace, method) else: scoped_method = method # set the timeout from the global method timeout tracker for this # method self._original_context.timeout = self._METHOD_TIMEOUTS[scoped_method] try: return self._original_context.call(ctxt, method, **kwargs) except oslo_messaging.MessagingTimeout: with excutils.save_and_reraise_exception(): wait = random.uniform( 0, min(self._METHOD_TIMEOUTS[scoped_method], TRANSPORT.conf.rpc_response_timeout) ) LOG.error("Timeout in RPC method %(method)s. Waiting for " "%(wait)s seconds before next attempt. If the " "server is not down, consider increasing the " "rpc_response_timeout option as Neutron " "server(s) may be overloaded and unable to " "respond quickly enough.", {'wait': int(round(wait)), 'method': scoped_method}) new_timeout = min( self._original_context.timeout * 2, self.get_max_timeout()) if new_timeout > self._METHOD_TIMEOUTS[scoped_method]: LOG.warning("Increasing timeout for %(method)s calls " "to %(new)s seconds. Restart the agent to " "restore it to the default value.", {'method': scoped_method, 'new': new_timeout}) self._METHOD_TIMEOUTS[scoped_method] = new_timeout time.sleep(wait) class BackingOffClient(oslo_messaging.RPCClient): """An oslo messaging RPC Client that implements a timeout backoff. This has all of the same interfaces as oslo_messaging.RPCClient but if the timeout parameter is not specified, the _BackingOffContextWrapper returned will track when call timeout exceptions occur and exponentially increase the timeout for the given call method. """ def prepare(self, *args, **kwargs): ctx = super(BackingOffClient, self).prepare(*args, **kwargs) # don't back off contexts that explicitly set a timeout if 'timeout' in kwargs: return _ContextWrapper(ctx) return _BackingOffContextWrapper(ctx) @staticmethod def set_max_timeout(max_timeout): '''Set RPC timeout ceiling for all backing-off RPC clients.''' _BackingOffContextWrapper.set_max_timeout(max_timeout) def get_client(target, version_cap=None, serializer=None): assert TRANSPORT is not None serializer = RequestContextSerializer(serializer) return BackingOffClient(TRANSPORT, target, version_cap=version_cap, serializer=serializer) def get_server(target, endpoints, serializer=None): assert TRANSPORT is not None serializer = RequestContextSerializer(serializer) access_policy = dispatcher.DefaultRPCAccessPolicy return oslo_messaging.get_rpc_server(TRANSPORT, target, endpoints, 'eventlet', serializer, access_policy=access_policy) def get_notifier(service=None, host=None, publisher_id=None): assert NOTIFIER is not None if not publisher_id: publisher_id = "%s.%s" % (service, host or cfg.CONF.host) return NOTIFIER.prepare(publisher_id=publisher_id) class RequestContextSerializer(om_serializer.Serializer): """This serializer is used to convert RPC common context into Neutron Context. """ def __init__(self, base=None): super(RequestContextSerializer, self).__init__() self._base = base def serialize_entity(self, ctxt, entity): if not self._base: return entity return self._base.serialize_entity(ctxt, entity) def deserialize_entity(self, ctxt, entity): if not self._base: return entity return self._base.deserialize_entity(ctxt, entity) def serialize_context(self, ctxt): _context = ctxt.to_dict() prof = profiler.get() if prof: trace_info = { "hmac_key": prof.hmac_key, "base_id": prof.get_base_id(), "parent_id": prof.get_id() } _context['trace_info'] = trace_info return _context def deserialize_context(self, ctxt): rpc_ctxt_dict = ctxt.copy() trace_info = rpc_ctxt_dict.pop("trace_info", None) if trace_info: profiler.init(**trace_info) return context.Context.from_dict(rpc_ctxt_dict) @profiler.trace_cls("rpc") class Service(service.Service): """Service object for binaries running on hosts. A service enables rpc by listening to queues based on topic and host. """ def __init__(self, host, topic, manager=None, serializer=None): super(Service, self).__init__() self.host = host self.topic = topic self.serializer = serializer if manager is None: self.manager = self else: self.manager = manager def start(self): super(Service, self).start() self.conn = create_connection() LOG.debug("Creating Consumer connection for Service %s", self.topic) endpoints = [self.manager] self.conn.create_consumer(self.topic, endpoints) # Hook to allow the manager to do other initializations after # the rpc connection is created. if callable(getattr(self.manager, 'initialize_service_hook', None)): self.manager.initialize_service_hook(self) # Consume from all consumers in threads self.conn.consume_in_threads() 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.conn.close() except Exception: # nosec pass super(Service, self).stop() class Connection(object): def __init__(self): super(Connection, self).__init__() self.servers = [] def create_consumer(self, topic, endpoints, fanout=False): target = oslo_messaging.Target( topic=topic, server=cfg.CONF.host, fanout=fanout) server = get_server(target, endpoints) self.servers.append(server) def consume_in_threads(self): for server in self.servers: server.start() return self.servers def close(self): for server in self.servers: server.stop() for server in self.servers: server.wait() class VoidConnection(object): def create_consumer(self, topic, endpoints, fanout=False): pass def consume_in_threads(self): pass def close(self): pass # functions def create_connection(): # NOTE(salv-orlando): This is a clever interpretation of the factory design # patter aimed at preventing plugins from initializing RPC servers upon # initialization when they are running in the REST over HTTP API server. # The educated reader will perfectly be able that this a fairly dirty hack # to avoid having to change the initialization process of every plugin. if RPC_DISABLED: return VoidConnection() return Connection()