Using mqtt paho for Python in a raspberry pi

Question

I'm trying to connect to message broker using python 2.7 in raspbian as follows:

import paho.mqtt.client as paho


host="messagesight.demos.ibm.com"
port=1883

def on_connect(pahoClient, obj, rc):
# Once connected, publish message
        print "Connected Code = %d"%(rc)
        client.publish("prueba/123", "Hello World", 0)


def on_log(pahoClient, obj, level, string):
        print string

def on_publish(pahoClient, packet, mid):
# Once published, disconnect
        print "Published"
        pahoClient.disconnect()

def on_disconnect(pahoClient, obj, rc):
        print "Disconnected"

# Create a client instance
client=paho.Client()

# Register callbacks
client.on_connect = on_connect
client.on_log = on_log
client.on_publish = on_publish
client.on_disconnnect = on_disconnect

#Set userid and password
client.username_pw_set(userID, password)

#connect
x = client.connect(host, port, 60)

client.loop_forever()

When I run the script, Im getting the following error:

Traceback (most recent call last): File "ejemplo.py", line 27, in client=paho.Client() File "/usr/local/lib/python2.7/dist-packages/paho/mqtt/client.py", line 410, in init self._sockpairR, self._sockpairW = _socketpair_compat() File "/usr/local/lib/python2.7/dist-packages/paho/mqtt/client.py", line 255, in _socketpair_compat listensock.bind(("localhost", 0)) File "/usr/lib/python2.7/socket.py", line 224, in meth return getattr(self._sock,name)(*args) socket.error: [Errno 99] Cannot assign requested address

How can I fix it?

Solution

I just quickly tired your code and it is publishing to messagesight.demos.ibm.com fine.

The only thing I did was comment out the userID, password.

#client.username_pw_set(userID, password)

Have you installed Paho Python Client correctly, also good example there as well. http://www.eclipse.org/paho/clients/python/

Comments

[ralight]

Feels a bit odd writing this, but do you have IPv4 support on your Pi?

[ralight]

Or perhaps your "lo" interface is down. Try ifconfig lo down; ifconfig lo up

[Maria Borbonés]

yes, Paho Python client is correctly installed... it is still not working. We are still getting the same issue " cannot assing requested address". Which is the content of your client.py file? Can you locate line 260 "listensock.bind(("127.0.0.1", 0))"? Thanks!

[Andy Piper]

can you provide the output of ifconfig -a

[Matt.]

@maria sounds like what the other guys are mentioning , chi network config.

[Maria Borbonés]

thanks, you are right! The problem was the /etc/network/interfaces file, it was not configured properly ...

[Isa A]

For other people, what @MariaBorbones and @Matt was referring to was the comment on the question. The problem is that lo or loopback interface is down. you can enable it using sudo ifconfig lo up