Synnefo

#!/usr/bin/env python

# Copyright 2011 GRNET S.A. All rights reserved.

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import sys

import logging

from optparse import OptionParser

try:

    from carrot.connection import BrokerConnection

    from carrot.messaging import Consumer

    from carrot.messaging import Publisher

except ImportError:

    sys.stderr.write("Dispatcher requires 'carrot' python library to " \

                     "be installed\n")

    sys.exit(1)

BROKER_HOST = 'localhost'

BROKER_PORT = 5672

BROKER_USER = 'guest'

BROKER_PASSWORD = 'guest'

BROKER_VHOST = '/'

CONSUMER_QUEUE = 'feed'

CONSUMER_EXCHANGE = 'sample'

CONSUMER_KEY = '#'

DEBUG = False

def main():

    parser = OptionParser()

    parser.add_option('-v', '--verbose', action='store_true', default=False,

                      dest='verbose', help='Enable verbose logging')

    parser.add_option('--host', default=BROKER_HOST, dest='host',

                      help='RabbitMQ host (default: %s)' % BROKER_HOST)

    parser.add_option('--port', default=BROKER_PORT, dest='port',

                      help='RabbitMQ port (default: %s)' % BROKER_PORT, type='int')

    parser.add_option('--user', default=BROKER_USER, dest='user',

                      help='RabbitMQ user (default: %s)' % BROKER_USER)

    parser.add_option('--password', default=BROKER_PASSWORD, dest='password',

                      help='RabbitMQ password (default: %s)' % BROKER_PASSWORD)

    parser.add_option('--vhost', default=BROKER_VHOST, dest='vhost',

                      help='RabbitMQ vhost (default: %s)' % BROKER_VHOST)

    parser.add_option('--queue', default=CONSUMER_QUEUE, dest='queue',

                      help='RabbitMQ queue (default: %s)' % CONSUMER_QUEUE)

    parser.add_option('--exchange', default=CONSUMER_EXCHANGE, dest='exchange',

                      help='RabbitMQ exchange (default: %s)' % CONSUMER_EXCHANGE)

    parser.add_option('--key', default=CONSUMER_KEY, dest='key',

                      help='RabbitMQ key (default: %s)' % CONSUMER_KEY)

    parser.add_option('--callback', default=None, dest='callback',

                      help='Callback function to consume messages')

    parser.add_option('--test', action='store_true', default=False,

                      dest='test', help='Produce a dummy message for testing')

    opts, args = parser.parse_args()

    if opts.verbose:

        DEBUG = True

    logging.basicConfig(format='%(asctime)s [%(levelname)s] %(name)s %(message)s',

                        datefmt='%Y-%m-%d %H:%M:%S',

                        level=logging.DEBUG if DEBUG else logging.INFO)

    logger = logging.getLogger('dispatcher')

    conn = BrokerConnection(hostname=opts.host, port=opts.port,

                            userid=opts.user, password=opts.password,

                            virtual_host=opts.vhost)

    if opts.test:

        publisher = Publisher(connection=conn,

                              exchange=opts.exchange, routing_key=opts.key,

                              exchange_type="topic")

        publisher.send({"test": "0123456789"})

        publisher.close()

        conn.close()

        sys.exit()

    consumer = Consumer(connection=conn, queue=opts.queue,

                        exchange=opts.exchange, routing_key=opts.key,

                        exchange_type="topic")

    callback = None

    if opts.callback:

        cb = opts.callback.rsplit('.', 1)

        if len(cb) == 2:

            __import__(cb[0])

            cb_module = sys.modules[cb[0]]

            callback = getattr(cb_module, cb[1])

    def process_message(message_data, message):

        logger.debug('%s', message_data)

        if callback:

            callback(message_data)

        message.ack()

    consumer.register_callback(process_message)

    try:

        consumer.wait()

    except KeyboardInterrupt:

        pass

if __name__ == '__main__':

    main()