All event handlers in NOX *really* only get a single parameter -- an event object. The trick is that when you use a helper to register for the event, such as self.register_for_packet_in(), it generates a new event handler function (with a single parameter), which then "breaks out" some of values from the event object and uses them as parameters to the multiple-parameter handler function you gave it. The generation of this intermediate handler function happens in src/nox/lib/util.py in functions such as gen_packet_in_callback() (which has just been called from register_for_packet_in() in core.py).
Hope that helps. -- Murphy On Aug 18, 2011, at 9:31 PM, Chen Gao wrote: > Dear All, > > I’m confused about how do arguments for method callback in component come out. > > For example, I register an event in install like > self.register_for_packet_in(packet_in_callback). > Then, I can do some stuff corresponding to packet_in_event in > packet_in_callback method. > My question is in the > > def packet_in_callback(dpid, inport, reason, len, bufid, packet) > > how do the arguments dpid, inport, reason, len, bufid, packet come out ? > > I understand that according to registering different events, NOX would > generate corresponding parameters for using by corresponding callback method. > Such as for packet_in_event, NOX generate dpid, inport, reason, len, bufid, > packet. > For datapath_leave event, NOX only generate parameter dpid for callback > method uses. > > Is my understanding right? If not, could someone explain how do these > arguments for callback method come out? > > Thank you very much in advance. > > Best regards, > Chen > _______________________________________________ > nox-dev mailing list > nox-dev@noxrepo.org > http://noxrepo.org/mailman/listinfo/nox-dev
_______________________________________________ nox-dev mailing list nox-dev@noxrepo.org http://noxrepo.org/mailman/listinfo/nox-dev
