On Thu, Sep 17, 2009 at 4:35 AM, Matt Perry <m...@unshift.net> wrote: > Make sure you're using the @inlineCallbacks decorator and the yield > statement referenced previously. Without those you're just adding several > callbacks to the same Deferred; with them, the function will wait until the > Deferred fires before continuing. > > def logRequest(self, *arg, **kw): > obj = copy.deepcopy(kw['obj']) > > d = self.db.runInteraction(obj.first) > > d.addCallback(self.db.runInteraction, obj.second, param1, param2) > d.addErrback(log.err) > > d.addCallback(self.db.runInteraction, obj.third) > d.addErrback(log.err) > > > Note that "d" is the same Deferred throughout. If you change it to: > > @inlineCallbacks > def logRequest(self, *arg, **kw): > obj = copy.deepcopy(kw['obj']) > > firstDeferred = self.db.runInteraction(obj.first) > yield firstDeferred > > # code here won't get resumed until "firstDeferred" has a result > print firstDeferred.result > > secondDeferred = self.db.runInteraction(obj.second) > yield secondDeferred > > # same as above, code won't get executed until "secondDeferred" has a > result > > then you'll get the behavior you're looking for. > > See > http://twistedmatrix.com/documents/8.2.0/api/twisted.internet.defer.html#inlineCallbacks > for some more information. >
Matt and Jean-Paul, thank you for help! Pet > - Matt > > > > On Wed, Sep 16, 2009 at 12:18 PM, Pet <petshm...@googlemail.com> wrote: >> >> On Tue, Sep 15, 2009 at 6:21 PM, Pet <petshm...@googlemail.com> wrote: >> > On Tue, Sep 15, 2009 at 5:19 PM, Mark Visser <ma...@lumierevfx.com> >> > wrote: >> >> exar...@twistedmatrix.com wrote: >> >>> On 10:37 am, petshm...@googlemail.com wrote: >> >>>> >> >>>> I'd like to run several queries in background, some of them may fail. >> >>>> >> >>> >> >>> If you have a function along the lines of this one: >> >>> >> >>> def someInteractions(db): >> >>> interactions = [ >> >>> db.runInteraction(one), >> >>> db.runInteraction(two), >> >>> db.runInteraction(three)] >> >>> >> >>> Then a failure in one shouldn't affect two or three; likewise for any >> >>> other failure or combination of failures. They are naturally (ugh, >> >>> not >> >>> a good word, but I can't think of a better one) independent. You have >> >>> to go out of your way to associate them somehow. >> >>> >> >> I think he might mean he wants them to run sequentially, even if one >> >> fails. >> >> >> >> You can do that explicitly via @inlineCallbacks like this: >> >> >> >> @inlineCallbacks >> >> def someInteractions(db): >> >> try: >> >> yield db.runInteraction(one) >> >> except: >> >> pass >> >> >> >> try: >> >> yield db.runInteraction(two) >> >> except: >> >> pass >> >> >> >> try: >> >> yield db.runInteraction(three) >> >> except: >> >> pass >> >> >> >> Or with callback/errbacks, like this: >> >> >> >> def someInteractions(db) >> >> d = db.runInteraction(one).addBoth(db.runInteraction, >> >> two).addBoth(db.runInteraction, three) >> > >> >> Hi, >> >> >> I've tried to do following: >> >> def logRequest(self, *arg, **kw): >> obj = copy.deepcopy(kw['obj']) >> >> d = self.db.runInteraction(obj.first) >> >> d.addCallback(self.db.runInteraction, obj.second, param1, param2) >> d.addErrback(log.err) >> >> d.addCallback(self.db.runInteraction, obj.third) >> d.addErrback(log.err) >> >> >> unfortunately it doesn't work in that way, because I suppose, obj is >> destroyed if second or third interaction starts. >> Is there a way to solve this? >> >> Thanks, Pet >> >> > Hi Mark! >> > >> > Yes, I'd like run them sequentially, it was not clear for me, how to >> > do it in one deferred. >> > >> > I will try your suggestions out. >> > >> > Thanks for help! >> > >> > Pet >> > >> >> >> >> addBoth is a convenience method that adds the same function as a >> >> callback and an errback: >> >> >> >> >> >> http://twistedmatrix.com/documents/8.2.0/api/twisted.internet.defer.Deferred.html#addBoth >> >> >> >> -- >> >> Mark Visser, Software Director >> >> Lumière VFX >> >> Email: ma...@lumierevfx.com >> >> Phone: +1-514-316-1080 x3030 >> >> >> >> >> >> _______________________________________________ >> >> Twisted-Python mailing list >> >> Twisted-Python@twistedmatrix.com >> >> http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python >> >> >> > >> >> _______________________________________________ >> Twisted-Python mailing list >> Twisted-Python@twistedmatrix.com >> http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python > > > _______________________________________________ > Twisted-Python mailing list > Twisted-Python@twistedmatrix.com > http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python > > _______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
