I added the necessary arguments in the definition of the Event and it
worked. Thank you very much!
About the way the events are raised, i am trying to find another
solution that
doesn't involve the use of of_01. I only used this approach because
out of
the many solutions i tried, only this one worked.
I looked up a bit and i noticed that the GoingUp Event in core.py is
raised like this:"core.raiseEvent(GoingUp/*() */) "
So at first i thought that i found the mistake i made in my previous
attempts
and did some tweaking in the _handle_PacketIn of the l2_learning module:
"core._eventMixin_events.add(CustomEvent)"
"core.raiseEvent(CustomEvent(event.connection, msg))"
Nothing happened. However if i delete the first command i get an error
saying what i expected, that i haven't add the CustomEvent to the
event set.
Also if i add the command "core.raiseEvent(CustomEvent(msg))"
i get another error saying as expected that __init__() expects 3
arguments.
If i provide the arguments needed like i did before nothing happens.
The commands core.raiseEvent(CustomEvent) and/or
core.raiseEvent(CustomEvent, msg) don't work without raising any errors.
If i replace with core.raiseEvent(CustomEvent()) a TypeError is
raised as i said above.
This is a skeleton of my component:
CustomModule.py:
class CustomModule (EventMixin):
def __init__ (self):
self.listenTo(core.openflow)
log.debug("...Enabling Custom Module...")
def _handle_CustomEvent (self, event):
log.debug(‘Event was raised!!!’)
def _handle_FlowRemoved (self, event):
log.debug('Flow Removed from switch: %s', event.connection)
self._eventMixin_events = set([SpamSpam,])
self.raiseEvent(SpamSpam(event.connection, event.ofp))
def launch ():
'''
Starting the module
'''
core.registerNew(CustomModule)
I tried raising the event, when a flow is removed. Nothing happens
this way either.
I don't know if am missing something obvious or if i should try
anything else.
In any case, thanks again for all your help so far, i really
appreciate it.
On Thu, Nov 6, 2014 at 12:30 AM, Murphy McCauley
<murphy.mccau...@gmail.com <mailto:murphy.mccau...@gmail.com>> wrote:
On Nov 5, 2014, at 2:48 AM, Adam Pavlidis <adampavli...@gmail.com
<mailto:adampavli...@gmail.com>> wrote:
I also found it strange that i get no error message whatsoever.
I was always running POX with --verbose plus log.level —DEBUG,
and i did not use .raiseEventNoErrors() method.
I haven't really given much thought on how i want the events to be
raised, i experimented a little in order to find a way that works.
Adding the CustomEvent, in the _eventMixin set of OpenFlowNexus and
did the trick.
In the end it doesn’t really matter for me which way the event
is raised.
I have a module, with 2 distinct functions.
1. Flow removal that is called automatically
2. Flow insertion that has to be manually called everywhere a
new flow is added.
I used the same logic as FlowRemoved, PacketIn e.t.c.
events/handlers,
so i added the following lines in of_01.py
def handle_CUSTOM_EVENT (con, msg): #A
e = con.ofnexus.raiseEvent(
CustomEvent, con, msg)
if e is None or e.halt != True:
con.raiseEvent(CustomEvent, con, msg)
and in order to call the above (e.g. l2_learning):
of_01.handle_CUSTOM_EVENT(event.connection, msg)
The above doesn't work unless i delete the arguments in
handle_CUSTOM_EVENT().
Traceback is:
File "/home/mininet/pox/pox/lib/revent/revent.py", line
234, in
raiseEventNoErrors
return self.raiseEvent(event, *args, **kw)
File "/home/mininet/pox/pox/lib/revent/revent.py", line
281, in raiseEvent
rv = event._invoke(handler, *args, **kw)
File "/home/mininet/pox/pox/lib/revent/revent.py", line
159, in _invoke
return handler(self, *args, **kw)
File "/home/mininet/pox/pox/forwarding/l2_learning.py",
line 182, in
_handle_PacketIn
of_01.handle_CUSTOM_EVENT(event.connection, msg)
File "/home/mininet/pox/pox/openflow/of_01.py", line 68, in
handle_CUSTOM_EVENT
e = con.ofnexus.raiseEvent(CustomEvent, con, msg)
File "/home/mininet/pox/pox/lib/revent/revent.py", line
265, in raiseEvent
event = eventType(*args, **kw)
TypeError: __init__() takes exactly 1 argument (3 given)
From what i understand raiseEvent method expects 1 argument but
receives 3. I don't understand however why
handle_PACKET_IN/FLOW_REMOVED
get to .raiseEventNoErrors the exact same way, and no TypeError
occurs.
Not quite. What it's actually talking about here is the
constructor for the event class itself. In your case, I am
guessing your CustomEvent.__init__() just took self. You'll want
to add additional parameters. As you say below, you want the
match, so you'd pass that into your event object's constructor.
Something to keep in mind:
foo.raiseEvent(BarEvent, spam, eggs)
.. is more or less the same as...
new_event = BarEvent(spam, eggs)
foo.raiseEvent(new_event)
The latter is perhaps a bit easier to understand, though.
Truth is i don't need the connection part, but is necessary for my
module that the msg.match object representing the flow that is
installed is
passed to the handler.
def _handle_CustomEvent(self, msg):
I don’t know if what i did is conceptually correct or if there is a
cleaner way (programming-wise). I just thought that using a separate
module instead of hard-coding the actions i need executed was
better,
considering i will also be able to pass some arguments from the
CLI to
the module less painfully, e.g. misc.CustomModule
--<server>_<hostname>.
I would greatly appreciate your opinion on this.
If there's no compelling reason, I think you shouldn't mess with
of_01/openflow at all. Keep your events within your own module.
Have your component register itself on core, and raise your two
new event types on your component instead of on the OpenFlowNexus
or Connection. Other components can listen there.
Thanks for all your help so far,
Adam Pavlidis
On Tue, Nov 4, 2014 at 12:42 AM, Murphy McCauley
<murphy.mccau...@gmail.com <mailto:murphy.mccau...@gmail.com>>
wrote:
I'm a bit surprised that you're getting no result at all as
opposed to, say, exceptions in the POX log. Have you tried
turning logging to DEBUG level and reading through to make
sure there are no hints as to what might be going wrong?
It's possible that raiseEventNoErrors() is masking the
exceptions. You might try at least temporarily replacing
such calls with just plain raiseEvent().
It looks like you want these events to be raised using the
same sources as normal OpenFlow events. Normally, sources
need to be aware of the events they'll be raising. In your
case, these sources are the Connection (in of_01) and
OpenFlowNexus (in openflow/__init__) classes. Have you
added your event to their set of _eventMixin_events?
On Nov 3, 2014, at 2:15 AM, Adam Pavlidis
<adampavli...@gmail.com <mailto:adampavli...@gmail.com>> wrote:
> Hello,
>
> i am trying to implement a controller module that handles
two types of Events:
> the already existing FlowRemoved and another of my own
creation
> "CustomEvent" that i will execute in various circumstances.
>
> I have read the section on custom events contained in the
POX manual
> (
https://openflow.stanford.edu/display/ONL/POX+Wiki#POXWiki-TheEventSystem%3Apox.lib.revent
> )
> and have successfully executed the examples.
>
> I have looked up a bit how the POX raises events such as
PacketIn.
> I added the following lines of code in
pox/pox/openflow/__init__.py
>
> class CustomEvent(Event):
> """
> Our own custom event
> """
> def __init__(self):
> Event.__init__(self)
>
> Then i added a handler for that event in an already
existing controller module,
>
> def _handle_CustomEvent (self, event):
> log.debug('The Event was raised successfully')
>
> However when i manually raise the above event,
> (e.g. during the handling of a PacketIn event in
> forwarding.l2_learning) nothing happens.
> I used both the method explained in the manual (creating a
subclass of
> EventMixin with _eventMixin_set=([CustomEvent], creating
an instance
> of that class and raising the event on that instance), and the
> core.raiselater method.
>
> Important note: In the same module there is a handler for
FlowRemoved
> Events, that is notified without issues, when a flow is
removed from the
> switch, so i don't think there is a listener issue.
>
> In my efforts to find the problem i tried to experiment in
> openflow/of_01.py and specifically in lines 85, 177 where
FlowRemoved
> and PacketIn events are raised from the Controller, i
tried to force
> raise my own
> event when a PacketIn was supposed to be raised.
>
> def handle_PACKET_IN (con, msg): #A
> e = con.ofnexus.raiseEventNoErrors(CustomEvent, con, msg)
> if e is None or e.halt != True:
> con.raiseEventNoErrors(CustomEvent, con, msg)
>
> Nothing happened either (apart from losing connectivity
between the hosts).
>
> I would appreciate any help,
> Adam Pavlidis
