#!/usr/bin/env python

 """

 AMQP Clock

 Fires off simple messages at one-minute intervals to a topic

 exchange named 'clock', with the topic of the message being

 the local time as 'year.month.date.dow.hour.minute',

 for example: '2007.11.26.1.12.33', where the dow (day of week)

 is 0 for Sunday, 1 for Monday, and so on (similar to Unix crontab).

 A consumer could then bind a queue to the routing key '#.0'

 for example to get a message at the beginning of each hour.

 2007-11-26 Barry Pederson <bp@barryp.org>

 """

 from datetime import datetime

 from optparse import OptionParser

 from time import sleep

 import amqplib.client_0_8 as amqp

 Message = amqp.Message

 EXCHANGE_NAME = 'clock'

 TOPIC_PATTERN = '%Y.%m.%d.%w.%H.%M' # Python datetime.strftime() pattern

 def main():

     parser = OptionParser()

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

                         help='AMQP server to connect to (default: %default)',

                         default='localhost')

     parser.add_option('-u', '--userid', dest='userid',

                         help='AMQP userid to authenticate as (default: %default)',

                         default='guest')

     parser.add_option('-p', '--password', dest='password',

                         help='AMQP password to authenticate with (default: %default)',

                         default='guest')

     parser.add_option('--ssl', dest='ssl', action='store_true',

                         help='Enable SSL with AMQP server (default: not enabled)',

                         default=False)

     options, args = parser.parse_args()

     conn = amqp.Connection(options.host, options.userid, options.password)

     ch = conn.channel()

     ch.access_request('/data', write=True, active=True)

     ch.exchange_declare(EXCHANGE_NAME, type='topic')

     # Make sure our first message is close to the beginning

     # of a minute

     now = datetime.now()

     if now.second > 0:

         sleep(60 - now.second)

     while True:

         now = datetime.now()

         msg = Message(timestamp=now)

         topic = now.strftime(TOPIC_PATTERN)

         ch.basic_publish(msg, EXCHANGE_NAME, routing_key=topic)

         # Don't know how long the basic_publish took, so

         # grab the time again.

         now = datetime.now()

         sleep(60 - now.second)

     ch.close()

     conn.close()

 if __name__ == '__main__':

     main()