On Nov 5, 2014, at 2:48 AM, Adam Pavlidis <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. > Flow removal that is called automatically > 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> > 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> 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 > >
