131 lines
4.2 KiB
Python
131 lines
4.2 KiB
Python
# Copyright 2010 United States Government as represented by the
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# Administrator of the National Aeronautics and Space Administration.
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# All Rights Reserved.
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# Copyright 2011 - 2012, Red Hat, Inc.
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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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"""
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Utilities for drivers based on the AMQPDriverBase.
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This module contains utility code used by drivers based on the AMQPDriverBase
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class. Specifically this includes the impl_rabbit driver.
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"""
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import collections
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import uuid
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from oslo_config import cfg
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from oslo_messaging._drivers import common as rpc_common
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amqp_opts = [
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cfg.BoolOpt('amqp_durable_queues',
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default=False,
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help='Use durable queues in AMQP, if rabbit_quorum_queue '
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'is enabled, queues will be durable and this value will '
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'be ignored'),
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cfg.BoolOpt('amqp_auto_delete',
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default=False,
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deprecated_group='DEFAULT',
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help='Auto-delete queues in AMQP.'),
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]
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UNIQUE_ID = '_unique_id'
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class RpcContext(rpc_common.CommonRpcContext):
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"""Context that supports replying to a rpc.call."""
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def __init__(self, **kwargs):
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self.msg_id = kwargs.pop('msg_id', None)
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self.reply_q = kwargs.pop('reply_q', None)
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super(RpcContext, self).__init__(**kwargs)
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def deepcopy(self):
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values = self.to_dict()
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values['conf'] = self.conf
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values['msg_id'] = self.msg_id
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values['reply_q'] = self.reply_q
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return self.__class__(**values)
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def unpack_context(msg):
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"""Unpack context from msg."""
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context_dict = {}
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for key in list(msg.keys()):
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key = str(key)
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if key.startswith('_context_'):
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value = msg.pop(key)
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context_dict[key[9:]] = value
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context_dict['msg_id'] = msg.pop('_msg_id', None)
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context_dict['reply_q'] = msg.pop('_reply_q', None)
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context_dict['client_timeout'] = msg.pop('_timeout', None)
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return RpcContext.from_dict(context_dict)
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def pack_context(msg, context):
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"""Pack context into msg.
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Values for message keys need to be less than 255 chars, so we pull
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context out into a bunch of separate keys. If we want to support
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more arguments in rabbit messages, we may want to do the same
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for args at some point.
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"""
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if isinstance(context, dict):
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context_d = context.items()
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else:
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context_d = context.to_dict().items()
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msg.update(('_context_%s' % key, value)
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for (key, value) in context_d)
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class _MsgIdCache(object):
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"""This class checks any duplicate messages."""
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# NOTE: This value is considered can be a configuration item, but
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# it is not necessary to change its value in most cases,
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# so let this value as static for now.
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DUP_MSG_CHECK_SIZE = 16
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def __init__(self, **kwargs):
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self.prev_msgids = collections.deque([],
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maxlen=self.DUP_MSG_CHECK_SIZE)
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def check_duplicate_message(self, message_data):
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"""AMQP consumers may read same message twice when exceptions occur
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before ack is returned. This method prevents doing it.
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"""
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try:
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msg_id = message_data.pop(UNIQUE_ID)
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except KeyError:
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return
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if msg_id in self.prev_msgids:
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raise rpc_common.DuplicateMessageError(msg_id=msg_id)
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return msg_id
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def add(self, msg_id):
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if msg_id and msg_id not in self.prev_msgids:
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self.prev_msgids.append(msg_id)
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def _add_unique_id(msg):
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"""Add unique_id for checking duplicate messages."""
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unique_id = uuid.uuid4().hex
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msg.update({UNIQUE_ID: unique_id})
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class AMQPDestinationNotFound(Exception):
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pass
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