[rabbitmq-discuss] Alternative Python AMQP client library

[Dmitriy Samovskiy]

Barry Pederson wrote:
> kyles wrote:
>>
>> Traceback (most recent call last):
>>   File "demo_send.py", line 56, in <module>
>>     main()
>>   File "demo_send.py", line 41, in main
>>     conn = amqp.Connection(options.host, userid=options.userid,
>> password=options.password, ssl=options.ssl)
>>   File "/usr/local/lib/python2.5/site-packages/amqplib/client_0_8.py", line
>> 180, in __init__
>>     self.close()
>>   File "/usr/local/lib/python2.5/site-packages/amqplib/client_0_8.py", line
>> 420, in close
>>     (10, 61),    # Connection.close_ok
>>   File "/usr/local/lib/python2.5/site-packages/amqplib/client_0_8.py", line
>> 356, in wait
>>     frame_type, payload = self._wait_channel(0)
>>   File "/usr/local/lib/python2.5/site-packages/amqplib/client_0_8.py", line
>> 298, in _wait_channel
>>     frame_type, frame_channel, payload = self._wait_frame()
>>   File "/usr/local/lib/python2.5/site-packages/amqplib/client_0_8.py", line
>> 273, in _wait_frame
>>     frame_type = self.input.read_octet()
>>   File "/usr/local/lib/python2.5/site-packages/amqplib/util_0_8.py", line
>> 96, in read_octet
>>     return unpack('B', self.input.read(1))[0]
>>   File "/usr/local/lib/python2.5/struct.py", line 87, in unpack
>>     return o.unpack(s)
>> struct.error: unpack requires a string argument of length 1
>> Exception socket.error: (32, 'Broken pipe') in <bound method
>> Connection.__del__ of <amqplib.client_0_8.Connection object at 0xb7c7470c>>
>> ignored
>>
>> Is this something you've seen before?
>>
>> Thanks,
>> Kyle
> 
> Sorry, I haven't had a multi-node RabbitMQ setup to try anything like
> that particular setup, so haven't seen that particular error.
> 
> It looks like the node you're connecting to is maybe trying to redirect
> you to the other node, and then closing the socket without waiting for
> the client to send a "close" message and then responding with "close-ok".
> 
Yes, I get the same very exception when broker replies with a redirect.

You can also use insist flag when starting a connection:

client = Connection(host=myip, userid='guest', password='guest', insist=True)

This should work with the latest version of amqplib.

In my tests I have never seen a broker respond with redirect when I set insist to True, 
even though according to the spec, a broker SHOULD accept a connection (not MUST):

       <field name="insist" type="bit">
     insist on connecting to server
     <doc>
       In a configuration with multiple load-sharing servers, the server
       may respond to a Connection.Open method with a Connection.Redirect.
       The insist option tells the server that the client is insisting on
       a connection to the specified server.
     </doc>
         <rule implement="SHOULD">
       When the client uses the insist option, the server SHOULD accept
       the client connection unless it is technically unable to do so.
     </rule>
       </field>


- Dmitriy