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<pre><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D">To note, if this is an easier description, I’m trying to implement the RPC example on the RabbitMQ tutorial with a synchronous connection. Which I’ve copied below so you guys don’t need to go find it. However, the main impetus to me moving forward is lines 13/14:<br><br></span></pre>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> result = self.channel.queue_declare(exclusive=True)</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> self.callback_queue = result.method.queue</span></p>
<pre><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D"> </span></pre>
<pre><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D">Line 13 declares the result variable as the product of the channel getting an exclusive queue created, which I get. However the part that I get caught up in is where the callback is set to result.method.queue in line 14. What exactly is the method.queue of the result object? I am hoping to simply modify my Monitor/Publish classes to be able to have a synchronous publish/monitor without creating 2 connections. My current attempt at simply using one connection with 2 channels does not seem to be operating how I expected.<br><br></span>#!/usr/bin/env python</pre>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New"">import pika</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New"">import uuid</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New"">class FibonacciRpcClient(object):</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> def __init__(self):</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> self.connection = pika.BlockingConnection(pika.ConnectionParameters(</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> host='localhost'))</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> self.channel = self.connection.channel()</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> result = self.channel.queue_declare(exclusive=True)</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> self.callback_queue = result.method.queue</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> self.channel.basic_consume(self.on_response, no_ack=True,</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> queue=self.callback_queue)</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> def on_response(self, ch, method, props, body):</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> if self.corr_id == props.correlation_id:</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> self.response = body</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> def call(self, n):</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> self.response = None</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> self.corr_id = str(uuid.uuid4())</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> self.channel.basic_publish(exchange='',</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> routing_key='rpc_queue',</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> properties=pika.BasicProperties(</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> reply_to = self.callback_queue,</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> correlation_id = self.corr_id,</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> ),</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> body=str(n))</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> while self.response is None:</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> self.connection.process_data_events()</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> return int(self.response)</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New"">fibonacci_rpc = FibonacciRpcClient()</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New""> </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New"">print " [x] Requesting fib(30)"</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New"">response = fibonacci_rpc.call(30)</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt; font-family:"Courier New"">print " [.] Got %r" % (response,)</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D">-Christopher Lefevre</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
<div style="border:none; border-top:solid #B5C4DF 1.0pt; padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span style="font-size:10.0pt; font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt; font-family:"Tahoma","sans-serif""> Michael Klishin [mailto:michael.s.klishin@gmail.com]
<br>
<b>Sent:</b> Tuesday, September 06, 2011 9:38 AM<br>
<b>To:</b> Christopher Lefevre<br>
<b>Cc:</b> rabbitmq-discuss@lists.rabbitmq.com<br>
<b>Subject:</b> Re: [rabbitmq-discuss] Publish on a queue, then Monitor on a reply queue, with only 1 connection to the RabbitMQ server? Non-blocking?</span></p>
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<p class="MsoNormal"> </p>
<p class="MsoNormal">2011/9/6 Christopher Lefevre <<a href="mailto:CLefevre@transparent.com">CLefevre@transparent.com</a>></p>
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<blockquote style="border:none; border-left:solid #CCCCCC 1.0pt; padding:0in 0in 0in 6.0pt; margin-left:4.8pt; margin-right:0in">
<p class="MsoNormal">Though I also wanted it to be non-blocking so the website isn’t stuck waiting for the reply, but rather can be updated as needed. Currently, I can get it to work if there is a pause, like when stepping through the program in a debugger,
but when it runs without myself stepping through, it simply hangs when the queue is created and the message is never picked up.</p>
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<p class="MsoNormal"><br>
Please post a code example that is at least similar to your actual code.<br clear="all">
</p>
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<p class="MsoNormal"> </p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">-- <br>
MK<br>
<br>
<a href="http://github.com/michaelklishin" target="_blank">http://github.com/michaelklishin</a><br>
<a href="http://twitter.com/michaelklishin" target="_blank">http://twitter.com/michaelklishin</a></p>
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