There seems to be a problem with Debian distributions (tested for both Wheezy and Squeeze) using Odoo for longpolling port. longpolling port is never used. It supposed to be used wen workers parameter is set to be greater than 0, but it is not used anyway. But testing same thing on Ubuntu, longpolling port is used normally.
There is an original Question (last comment of the issue) https://github.com/odoo/odoo/issues/3793
checking nginx log I see this (everytime it tries to access longpolling through reverse proxy):
2015/05/08 07:54:09 [error] 32494#0: *8 connect() failed (111: Connection refused) while connecting to upstream, client: IP address, server: _, request: "POST /longpolling/poll HTTP/1.1", upstream: "http://127.0.0.1:8072/longpolling/poll", host: "db.host.eu", referrer: "http://db.host.eu/web"
And when I try to connect to 8072 port via telnet:
$ telnet 127.0.0.1 8072
Trying 127.0.0.1...
telnet: Unable to connect to remote host: Connection refused
But trying for example:
$ telnet 127.0.0.1 8069
Trying 127.0.0.1...
Connected to 127.0.0.1.
So it seems that 8072 port is not used? In my odoo config it is set to be like this:
longpolling_port = 8072
xmlrpc_port = 8069
workers = 2
xmlrpc_interface = 127.0.0.1
netrpc_interface = 127.0.0.1
The problem was quite simple, but yet disguised. It was missing python package psycogreen. But it was not mentioned as dependency and when installing im_chat it didn't require such package. So if you were running Odoo with --workers=0, then installed im_chat and later switched to for example --workers=2, Odoo would not throw any error and longpolling port would never be opened.
Installing this solved it:
pip install psycogreen==1.0