66 lines
2.1 KiB
Python
66 lines
2.1 KiB
Python
# Copyright (c) 2013 Mirantis Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain 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,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import collections
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import socket
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import time
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from eventlet import patcher
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kombu = patcher.import_patched('kombu')
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from . import message
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class Subscription(object):
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def __init__(self, connection, queue, prefetch_count=1):
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self._buffer = collections.deque()
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self._connection = connection
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self._queue = kombu.Queue(name=queue, exchange=None)
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self._consumer = kombu.Consumer(self._connection, auto_declare=False)
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self._consumer.register_callback(self._receive)
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self._consumer.qos(prefetch_count=prefetch_count)
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def __enter__(self):
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self._consumer.add_queue(self._queue)
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self._consumer.consume()
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return self
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def __exit__(self, exc_type, exc_val, exc_tb):
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if self._consumer is not None:
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self._consumer.cancel()
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return False
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def get_message(self, timeout=None):
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msg_handle = self._get(timeout=timeout)
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if msg_handle is None:
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return None
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return message.Message(self._connection, msg_handle)
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def _get(self, timeout=None):
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elapsed = 0.0
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remaining = timeout
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while True:
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time_start = time.time()
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if self._buffer:
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return self._buffer.pop()
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try:
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self._connection.drain_events(timeout=timeout and remaining)
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except socket.timeout:
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return None
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elapsed += time.time() - time_start
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remaining = timeout and timeout - elapsed or None
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def _receive(self, message_data, message):
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self._buffer.append(message)
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