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# Copyright (c) 2016-2017 Intel Corporation
#
# 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.
""" AMQP Consumer scenario definition """
from __future__ import absolute_import
from __future__ import print_function
import logging
import pika
from pika.exceptions import AMQPConnectionError
class AmqpConsumer(object):
""" This Class handles amqp consumer and collects collectd data """
EXCHANGE = 'amq.fanout'
EXCHANGE_TYPE = 'fanout'
QUEUE = ''
ROUTING_KEY = 'collectd'
def __init__(self, amqp_url, queue):
super(AmqpConsumer, self).__init__()
self._connection = None
self._channel = None
self._closing = False
self._consumer_tag = None
self._url = amqp_url
self._queue = queue
def connect(self):
""" connect to amqp url """
try:
return pika.SelectConnection(pika.URLParameters(self._url),
self.on_connection_open,
stop_ioloop_on_close=False)
except AMQPConnectionError:
raise RuntimeError
def on_connection_open(self, unused_connection):
""" call back from pika & open channel """
logging.info("list of unused connections %s", unused_connection)
self._connection.add_on_close_callback(self.on_connection_closed)
self._connection.channel(on_open_callback=self.on_channel_open)
def on_connection_closed(self, connection, reply_code, reply_text):
""" close the amqp connections. if force close, try re-connect """
logging.info("amqp connection (%s)", connection)
self._channel = None
if self._closing:
self._connection.ioloop.stop()
else:
logging.debug(('Connection closed, reopening in 5 sec: (%s) %s',
reply_code, reply_text))
self._connection.add_timeout(5, self.reconnect)
def reconnect(self):
""" re-connect amqp consumer"""
self._connection.ioloop.stop()
if not self._closing:
self._connection = self.connect()
self._connection.ioloop.start()
def on_channel_open(self, channel):
""" add close callback & setup exchange """
self._channel = channel
self.add_on_channel_close_callback()
self._channel.exchange_declare(self.on_exchange_declareok,
self.EXCHANGE,
self.EXCHANGE_TYPE,
durable=True, auto_delete=False)
def add_on_channel_close_callback(self):
""" register for close callback """
self._channel.add_on_close_callback(self.on_channel_closed)
def on_channel_closed(self, channel, reply_code, reply_text):
""" close amqp channel connection """
logging.info("amqp channel closed channel(%s), "
"reply_code(%s) reply_text(%s)",
channel, reply_code, reply_text)
self._connection.close()
def on_exchange_declareok(self, unused_frame):
""" if exchange declare is ok, setup queue """
logging.info("amqp exchange unused frame (%s)", unused_frame)
self.setup_queue(self.QUEUE)
def setup_queue(self, queue_name):
""" setup queue & declare same with channel """
logging.info("amqp queue name (%s)", queue_name)
self._channel.queue_declare(self.on_queue_declareok, queue_name)
def on_queue_declareok(self, method_frame):
""" bind queue to channel """
logging.info("amqp queue method frame (%s)", method_frame)
self._channel.queue_bind(self._on_bindok, self.QUEUE,
self.EXCHANGE, self.ROUTING_KEY)
def _on_bindok(self, unused_frame):
""" call back on bind start consuming data from amqp queue """
logging.info("amqp unused frame %s", unused_frame)
self.add_on_cancel_callback()
self._consumer_tag = self._channel.basic_consume(self.on_message,
self.QUEUE)
def add_on_cancel_callback(self):
""" add cancel func to amqp callback """
self._channel.add_on_cancel_callback(self.on_consumer_cancelled)
def on_consumer_cancelled(self, method_frame):
""" on cancel close the channel """
logging.info("amqp method frame %s", method_frame)
if self._channel:
self._channel.close()
def on_message(self, unused_channel, basic_deliver, properties, body):
""" parse received data from amqp server (collectd) """
logging.info("amqp unused channel %s, properties %s",
unused_channel, properties)
metrics = body.rsplit()
self._queue.put({metrics[1]: metrics[3]})
self.ack_message(basic_deliver.delivery_tag)
def ack_message(self, delivery_tag):
""" acknowledge amqp msg """
self._channel.basic_ack(delivery_tag)
def on_cancelok(self, unused_frame):
""" initiate amqp close channel on callback """
logging.info("amqp unused frame %s", unused_frame)
self._channel.close()
def run(self):
""" Initiate amqp connection. """
self._connection = self.connect()
self._connection.ioloop.start()
def stop(self):
""" stop amqp consuming data """
self._closing = True
if self._channel:
self._channel.basic_cancel(self.on_cancelok, self._consumer_tag)
if self._connection:
self._connection.ioloop.start()
def close_connection(self):
""" close amqp connection """
self._connection.close()
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