pyrabbit.py

   1 # -*- coding: utf-8 -*-
   2 ##############################################################################
   3 #
   4 #    pyrabbit, a Python library for easy playing with RabbitMQ
   5 #    Copyright (C) 2013 by Javier Sancho Fernandez <jsf at jsancho dot org>
   6 #
   7 #    This program is free software: you can redistribute it and/or modify
   8 #    it under the terms of the GNU General Public License as published by
   9 #    the Free Software Foundation, either version 3 of the License, or
  10 #    (at your option) any later version.
  11 #
  12 #    This program is distributed in the hope that it will be useful,
  13 #    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 #    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 #    GNU General Public License for more details.
  16 #
  17 #    You should have received a copy of the GNU General Public License
  18 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 #
  20 ##############################################################################
  21
  22 import errno
  23 import os
  24 import pika
  25 import signal
  26 import uuid
  27
  28 class TimeoutError(Exception):
  29     pass
  30
  31 class Connection(object):
  32     def __init__(self, host):
  33         self.host = host
  34         self.open(host=self.host)
  35
  36     def open(self, host=None):
  37         if host is None:
  38             host = self.host
  39         self.connection = pika.BlockingConnection(pika.ConnectionParameters(host=host))
  40         self.channel = self.connection.channel()
  41         self.callback_queue = None
  42
  43     def close(self):
  44         self.channel.cancel()
  45         self.connection.close()
  46
  47     def __getattr__(self, queue_name):
  48         return Queue(self, queue_name)
  49
  50     def __getitem__(self, queue_name):
  51         return self.__getattr__(queue_name)
  52
  53
  54 class Queue(object):
  55     def __init__(self, connection, queue_name):
  56         self.connection = connection
  57         self.queue_name = queue_name
  58         self.connection.channel.queue_declare(queue=self.queue_name)
  59
  60     def receive(self, timeout=0, queue_name=None):
  61         if queue_name is None:
  62             queue_name = self.queue_name
  63         def _handle_timeout(signum, frame):
  64             raise TimeoutError(os.strerror(errno.ETIME))
  65         signal.signal(signal.SIGALRM, _handle_timeout)
  66         signal.alarm(timeout)
  67         res = None
  68         try:
  69             method, properties, body = self.connection.channel.consume(queue_name).next()
  70             res = Message(self.connection, method, properties, body)
  71         finally:
  72             signal.alarm(0)
  73         return res
  74
  75     def send(self, body, wait_response=False, timeout=0):
  76         properties = None
  77
  78         if wait_response:
  79             corr_id = str(uuid.uuid4())
  80             if self.connection.callback_queue is None:
  81                 self.connection.callback_queue = self.connection.channel.queue_declare(exclusive=True).method.queue
  82             properties = pika.BasicProperties(
  83                 reply_to=self.connection.callback_queue,
  84                 correlation_id=corr_id,
  85                 )
  86         else:
  87             properties = pika.BasicProperties()
  88
  89         self.connection.channel.basic_publish(exchange='',
  90                                               routing_key=self.queue_name,
  91                                               properties=properties,
  92                                               body=body)
  93
  94         response = None
  95         if wait_response:
  96             response = self.receive(timeout=timeout, queue_name=self.connection.callback_queue)
  97
  98         return response
  99
 100
 101 class Message(object):
 102     def __init__(self, connection, method, properties, body):
 103         self.connection = connection
 104         self.method = method
 105         self.properties = properties
 106         self.body = body
 107
 108     def ack(self):
 109         self.connection.channel.basic_ack(delivery_tag=self.method.delivery_tag)
 110
 111     def response(self, body):
 112         print self.properties
 113         print self.properties.reply_to
 114         if self.properties.reply_to:
 115             self.connection.channel.basic_publish(exchange='',
 116                                                   routing_key=self.properties.reply_to,
 117                                                   properties=pika.BasicProperties(correlation_id=self.properties.correlation_id),
 118                                                   body=body)