d'oh! Thanks Murphy, I can't believe I didn't catch that. I thought
the event handler was firing thrice and printing an individual
ofp_port_stats object each time.
I'd facepalm but I have a headache now...
2014-04-23 16:58 GMT-04:00 Murphy McCauley <murphy.mccau...@gmail.com>:
> On Apr 23, 2014, at 1:54 PM, Alison Chan <chan7...@kettering.edu> wrote:
>
>> I am trying to access the port_no field of an ofp_port_stats reply
>> object. printing the object suggests that it is an ofp_port_stats
>> object, but trying to access its port_no field results in an
>> AttributeError: 'list' object has no attribute 'port_no'. How do I
>> access its port_no and other fields?
>
> Well there's your problem. ;) It's a list, not an ofp_port_stats.
>
>> [16:24:42] erinacity:~/Code/pox
>> alisonc $ ./pox.py openflow.of_01 py
>> [snip startup crap]
>> POX> import pox.openflow.libopenflow_01 as of
>> POX>
>> POX> def handle_port_stats(event):
>> ... print event.stats
>> ... print event.stats.port_no
>> ...
>> POX> core.openflow.addListenerByName("PortStatsReceived", handle_port_stats)
>> (<class 'pox.openflow.PortStatsReceived'>, 14)
>> POX>
>> core.openflow.connections[1].send(of.ofp_stats_request(body=of.ofp_port_stats_request(port_no=of.OFPP_NONE)))
>> POX> [<pox.openflow.libopenflow_01.ofp_port_stats object at
>> 0x2a57ad0>, <pox.openflow.libopenflow_01.ofp_port_stats object at
>> 0x2a57a10>, <pox.openflow.libopenflow_01.ofp_port_stats object at
>> 0x2a57b50>]
>
> And there's your list. Of ofp_port_stats.
>
> Try...
> print [p.port_no for p in event.stats]
>
> Or just print event.stats[0].port_no to print only the first one.
>
>> ERROR:core:Exception while handling OpenFlowNexus!PortStatsReceived...
>> Traceback (most recent call last):
>> File "/home/alisonc/Code/pox/pox/lib/revent/revent.py", line 231, in
>> raiseEventNoErrors
>> return self.raiseEvent(event, *args, **kw)
>> File "/home/alisonc/Code/pox/pox/lib/revent/revent.py", line 278, in
>> raiseEvent
>> rv = event._invoke(handler, *args, **kw)
>> File "/home/alisonc/Code/pox/pox/lib/revent/revent.py", line 156, in _invoke
>> return handler(self, *args, **kw)
>> File "<console>", line 3, in handle_port_stats
>> AttributeError: 'list' object has no attribute 'port_no'
>>
>> Cheers,
>> --
>> Alison Chan
>> chan7...@kettering.edu
>> SMS: +1 909 278 7753
>> Fax: +1 206 203 2793
>
> -- Murphy
--
Alison Chan
chan7...@kettering.edu
SMS: +1 909 278 7753
Fax: +1 206 203 2793
