deb-murano/murano/common/messaging/subscription.py
Ravi Shekhar Jethani 7ea4442e9c Fix import order of modules
Make corrections in import order for six, yaml, eventlet and
greenlet as per OpenStack import standards [1].

[1] http://docs.openstack.org/developer/hacking/#import-order-template

Change-Id: I26feb4adb81e8b07a7a36ac7f0a6235536a8c119
2016-01-24 23:34:03 -08:00

68 lines
2.2 KiB
Python

# Copyright (c) 2013 Mirantis 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.
import collections
import socket
import time
from eventlet import patcher
from murano.common.messaging import message
kombu = patcher.import_patched('kombu')
class Subscription(object):
def __init__(self, connection, queue, prefetch_count=1):
self._buffer = collections.deque()
self._connection = connection
self._queue = kombu.Queue(name=queue, exchange=None)
self._consumer = kombu.Consumer(self._connection, auto_declare=False)
self._consumer.register_callback(self._receive)
self._consumer.qos(prefetch_count=prefetch_count)
def __enter__(self):
self._consumer.add_queue(self._queue)
self._consumer.consume()
return self
def __exit__(self, exc_type, exc_val, exc_tb):
if self._consumer is not None:
self._consumer.cancel()
return False
def get_message(self, timeout=None):
msg_handle = self._get(timeout=timeout)
if msg_handle is None:
return None
return message.Message(self._connection, msg_handle)
def _get(self, timeout=None):
elapsed = 0.0
remaining = timeout
while True:
time_start = time.time()
if self._buffer:
return self._buffer.pop()
try:
self._connection.drain_events(timeout=timeout and remaining)
except socket.timeout:
return None
elapsed += time.time() - time_start
remaining = timeout and timeout - elapsed or None
def _receive(self, message_data, message):
self._buffer.append(message)