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#inlineCallbacksfor some more information. - 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 >
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