# Copyright 2010 United States Government as represented by the # Administrator of the National Aeronautics and Space Administration. # All Rights Reserved. # Copyright 2011 - 2012, Red Hat, Inc. # # 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. """ Shared code between AMQP based openstack.common.rpc implementations. The code in this module is shared between the rpc implementations based on AMQP. Specifically, this includes impl_kombu and impl_qpid. impl_carrot also uses AMQP, but is deprecated and predates this code. """ import collections import logging import uuid from oslo_config import cfg from oslo_utils import strutils import six from oslo_messaging._drivers import common as rpc_common from oslo_messaging._drivers import pool amqp_opts = [ cfg.BoolOpt('amqp_durable_queues', default=False, deprecated_name='rabbit_durable_queues', deprecated_group='DEFAULT', help='Use durable queues in AMQP.'), cfg.BoolOpt('amqp_auto_delete', default=False, help='Auto-delete queues in AMQP.'), # FIXME(markmc): this was toplevel in openstack.common.rpc cfg.IntOpt('rpc_conn_pool_size', default=30, help='Size of RPC connection pool.'), ] UNIQUE_ID = '_unique_id' LOG = logging.getLogger(__name__) class ConnectionPool(pool.Pool): """Class that implements a Pool of Connections.""" def __init__(self, conf, url, connection_cls): self.connection_cls = connection_cls self.conf = conf self.url = url super(ConnectionPool, self).__init__(self.conf.rpc_conn_pool_size) self.reply_proxy = None # TODO(comstud): Timeout connections not used in a while def create(self): LOG.debug('Pool creating new connection') return self.connection_cls(self.conf, self.url) def empty(self): for item in self.iter_free(): item.close() class ConnectionContext(rpc_common.Connection): """The class that is actually returned to the create_connection() caller. This is essentially a wrapper around Connection that supports 'with'. It can also return a new Connection, or one from a pool. The function will also catch when an instance of this class is to be deleted. With that we can return Connections to the pool on exceptions and so forth without making the caller be responsible for catching them. If possible the function makes sure to return a connection to the pool. """ def __init__(self, connection_pool, pooled=True): """Create a new connection, or get one from the pool.""" self.connection = None self.connection_pool = connection_pool if pooled: self.connection = connection_pool.get() else: # a non-pooled connection is requested, so create a new connection self.connection = connection_pool.create() self.pooled = pooled def __enter__(self): """When with ConnectionContext() is used, return self.""" return self def _done(self): """If the connection came from a pool, clean it up and put it back. If it did not come from a pool, close it. """ if self.connection: if self.pooled: # Reset the connection so it's ready for the next caller # to grab from the pool self.connection.reset() self.connection_pool.put(self.connection) else: try: self.connection.close() except Exception: pass self.connection = None def __exit__(self, exc_type, exc_value, tb): """End of 'with' statement. We're done here.""" self._done() def __del__(self): """Caller is done with this connection. Make sure we cleaned up.""" self._done() def close(self): """Caller is done with this connection.""" self._done() def __getattr__(self, key): """Proxy all other calls to the Connection instance.""" if self.connection: return getattr(self.connection, key) else: raise rpc_common.InvalidRPCConnectionReuse() class RpcContext(rpc_common.CommonRpcContext): """Context that supports replying to a rpc.call.""" def __init__(self, **kwargs): self.msg_id = kwargs.pop('msg_id', None) self.reply_q = kwargs.pop('reply_q', None) self.conf = kwargs.pop('conf') super(RpcContext, self).__init__(**kwargs) def deepcopy(self): values = self.to_dict() values['conf'] = self.conf values['msg_id'] = self.msg_id values['reply_q'] = self.reply_q return self.__class__(**values) def unpack_context(conf, msg): """Unpack context from msg.""" context_dict = {} for key in list(msg.keys()): key = six.text_type(key) if key.startswith('_context_'): value = msg.pop(key) context_dict[key[9:]] = value context_dict['msg_id'] = msg.pop('_msg_id', None) context_dict['reply_q'] = msg.pop('_reply_q', None) context_dict['conf'] = conf ctx = RpcContext.from_dict(context_dict) LOG.debug(u'unpacked context: %s', strutils.mask_password(six.text_type(ctx.to_dict()))) return ctx def pack_context(msg, context): """Pack context into msg. Values for message keys need to be less than 255 chars, so we pull context out into a bunch of separate keys. If we want to support more arguments in rabbit messages, we may want to do the same for args at some point. """ if isinstance(context, dict): context_d = six.iteritems(context) else: context_d = six.iteritems(context.to_dict()) msg.update(('_context_%s' % key, value) for (key, value) in context_d) class _MsgIdCache(object): """This class checks any duplicate messages.""" # NOTE: This value is considered can be a configuration item, but # it is not necessary to change its value in most cases, # so let this value as static for now. DUP_MSG_CHECK_SIZE = 16 def __init__(self, **kwargs): self.prev_msgids = collections.deque([], maxlen=self.DUP_MSG_CHECK_SIZE) def check_duplicate_message(self, message_data): """AMQP consumers may read same message twice when exceptions occur before ack is returned. This method prevents doing it. """ try: msg_id = message_data.pop(UNIQUE_ID) except KeyError: return if msg_id in self.prev_msgids: raise rpc_common.DuplicateMessageError(msg_id=msg_id) return msg_id def add(self, msg_id): if msg_id and msg_id not in self.prev_msgids: self.prev_msgids.append(msg_id) def _add_unique_id(msg): """Add unique_id for checking duplicate messages.""" unique_id = uuid.uuid4().hex msg.update({UNIQUE_ID: unique_id}) LOG.debug('UNIQUE_ID is %s.', unique_id)