> -----Original Message----- > From: Joshua Harlow [mailto:harlo...@outlook.com] > Sent: Tuesday, June 16, 2015 4:52 PM > To: OpenStack Development Mailing List (not for usage questions) > Subject: Re: [openstack-dev] [taskflow] Returning information from reverted > flow > > Dulko, Michal wrote: > >> -----Original Message----- > >> From: Joshua Harlow [mailto:harlo...@outlook.com] > >> Sent: Friday, June 12, 2015 5:49 PM > >> To: OpenStack Development Mailing List (not for usage questions) > >> Subject: Re: [openstack-dev] [taskflow] Returning information from > >> reverted flow > >> > >> Dulko, Michal wrote: > >>> Hi, > >>> > >>> In Cinder we had merged a complicated piece of code[1] to be able to > >>> return something from flow that was reverted. Basically outside we > >>> needed an information if volume was rescheduled or not. Right now > >>> this is done by injecting information needed into exception thrown > >>> from the flow. Another idea was to use notifications mechanism of > TaskFlow. > >>> Both ways are rather workarounds than real solutions. > >> Unsure about notifications being a workaround (basically u are > >> notifying to some other entities that rescheduling happened, which > >> seems like exactly what it was made for) but I get the point ;) > > > > Please take a look at this review - > https://review.openstack.org/#/c/185545/. Notifications cannot help if some > further revert decision needs to be based on something that happened > earlier. > > That sounds like conditional reverting, which seems like it should be handled > differently anyway, or am I misunderstanding something?
Current version of the patch takes another approach which I think handles it correctly. So you were probably right. :) > > >>> I wonder if TaskFlow couldn't provide a mechanism to mark stored > >>> element to not be removed when revert occurs. Or maybe another way > >>> of returning something from reverted flow? > >>> > >>> Any thoughts/ideas? > >> I have a couple, I'll make some paste(s) and see what people think, > >> > >> How would this look (as pseudo-code or other) to you, what would be > >> your ideal, and maybe we can work from there (maybe u could do some > >> paste(s) to and we can prototype it), just storing information that > >> is returned from revert() somewhere? Or something else? There has > >> been talk about task 'local storage' (or something like that/along > >> those lines) that could also be used for this similar purpose. > > > > I think that the easiest idea from the perspective of an end user would be > to save items returned from revert into flow engine's storage *and* do not > remove it from storage when whole flow gets reverted. This is completely > backward compatible, because currently revert doesn't return anything. And > if revert has to record some information for further processing - this will > also > work. > > > > Ok, let me see what this looks like and maybe I can have a POC in the next > few days, I don't think its impossible to do (obviously) and hopefully will be > useful for this. Great! > > >>> [1] https://review.openstack.org/#/c/154920/ > >>> > >>> > >> > __________________________________________________________ > >> ________________ > >>> OpenStack Development Mailing List (not for usage questions) > >>> Unsubscribe: OpenStack-dev- > >> requ...@lists.openstack.org?subject:unsubscribe > >>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > >> > __________________________________________________________ > >> ________________ > >> OpenStack Development Mailing List (not for usage questions) > >> Unsubscribe: OpenStack-dev- > >> requ...@lists.openstack.org?subject:unsubscribe > >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > > > > > __________________________________________________________ > ____________ > > ____ OpenStack Development Mailing List (not for usage questions) > > Unsubscribe: > > openstack-dev-requ...@lists.openstack.org?subject:unsubscribe > > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > > __________________________________________________________ > ________________ > OpenStack Development Mailing List (not for usage questions) > Unsubscribe: OpenStack-dev- > requ...@lists.openstack.org?subject:unsubscribe > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
