basic_publish of BlockingConnection does not raise exception after server down

[qwang2505]

We're using pika to connect rabbitmq, but in some condition, there's a chance that the basic_publish method still works even when server's down, and after restarting, the messages are missing. I tested with both the latest stable version(0.9.13) and the code in master in github.

Here is the script I used for test:

#!/usr/bin/env python
import pika
import time

connection = pika.BlockingConnection(pika.ConnectionParameters(
        host='localhost'))
channel = connection.channel()

channel.queue_declare(queue='hello')

count = 0
while True:
    try:
        print channel.basic_publish(exchange='', routing_key='hello', body='Hello World!')
        count += 1
        print 'send %d messages' % count
    except:
        break
    time.sleep(5)
connection.close()
print 'total send %d messages' % count

After the connection was made, I stopped the rabbitmq-server, but it kept printing "send N messages". I tested under ubuntu 12.04, python version is 2.7.3.

Please help fix this ASAP, we're using pika in product.

[eandersson]

You need to add channel.confirm_delivery() when setting up the channel.

[qwang2505]

Thanks! But I got another problem. When I added channel.confirm_delivery(), I got following exception:

Traceback (most recent call last):
File "send.py", line 21, in
connection.close()
File "/home/baina/pikatest/pika/adapters/blocking_connection.py", line 200, in close
self._send_connection_close(reply_code, reply_text)
File "/home/baina/pikatest/pika/connection.py", line 1438, in _send_connection_close
self._on_connection_closed, [spec.Connection.CloseOk])
File "/home/baina/pikatest/pika/connection.py", line 1428, in _rpc
self._send_method(channel_number, method_frame)
File "/home/baina/pikatest/pika/connection.py", line 1492, in _send_method
self._send_frame(frame.Method(channel_number, method_frame))
File "/home/baina/pikatest/pika/adapters/blocking_connection.py", line 396, in _send_frame
super(BlockingConnection, self)._send_frame(frame_value)
File "/home/baina/pikatest/pika/connection.py", line 1479, in _send_frame
self._flush_outbound()
File "/home/baina/pikatest/pika/adapters/blocking_connection.py", line 356, in _flush_outbound
if self._handle_write():
File "/home/baina/pikatest/pika/adapters/base_connection.py", line 338, in _handle_write
total_written += self.socket.send(frame[total_written:])
AttributeError: 'NoneType' object has no attribute 'send'

I'm hoping it would raise a ConnectionError or ChannelError, but why this? Do I miss something? Or it should be like this?

[eandersson]

That might be something worth looking into as I would also expect a proper Exception to be sent. I'll see what I can find out, but Gavin should be able to provide us with a better insight into this.

[qwang2505]

Thanks a lot! I will handle the AtrributeError in my code, but it should be a proper exception. I will leave this open to track this improper exception problem.

[eandersson]

I'll submit a fix in a couple of minutes.

False
send 1 messages
False
send 2 messages
False
send 3 messages
Traceback (most recent call last):
  File "/home/eandersson/repo/x/t2.py", line 25, in <module>
    connection.close()
  File "/usr/local/lib/python2.7/dist-packages/pika-0.9.13-py2.7.egg/pika/adapters/blocking_connection.py", line 197, in close
    self.process_data_events()
  File "/usr/local/lib/python2.7/dist-packages/pika-0.9.13-py2.7.egg/pika/adapters/blocking_connection.py", line 221, in process_data_events
    raise exceptions.ConnectionClosed()
pika.exceptions.ConnectionClosed

[qwang2505]

Thanks for help!

[William-Kong]

Was wondering whether this issue has been fixed or not?

I copied the posted code, and added the line "channel.confirm_delivery()", But for me, the basic_publish functions hangs there.

Done think it matters, but my os: Ubuntu 10.04.4 LTS

Thank you in advace

[William-Kong]

After I hit ctrl-c, I see this:

File "./test1.py", line 21, in
connection.close()
File "/usr/local/lib/python2.6/dist-packages/pika-0.9.14p0-py2.6.egg/pika/adapters/blocking_connection.py", line 211, in close
self.process_data_events()
File "/usr/local/lib/python2.6/dist-packages/pika-0.9.14p0-py2.6.egg/pika/adapters/blocking_connection.py", line 233, in process_data_events
if self._handle_read():
File "/usr/local/lib/python2.6/dist-packages/pika-0.9.14p0-py2.6.egg/pika/adapters/blocking_connection.py", line 345, in _handle_read
if self._read_poller.ready():
File "/usr/local/lib/python2.6/dist-packages/pika-0.9.14p0-py2.6.egg/pika/adapters/blocking_connection.py", line 36, in inner
return f(_args, *_kwargs)
File "/usr/local/lib/python2.6/dist-packages/pika-0.9.14p0-py2.6.egg/pika/adapters/blocking_connection.py", line 78, in ready
events = self.poller.poll(self.poll_timeout)

Thanks

[William-Kong]

Please ignore the previous post, regarding the ctrl-c, the code was trying to close the connection to the server, which is not accessible anymore.