Excerpts from Angus Salkeld's message of 2014-11-09 00:15:42 -0800: > On 06/11/2014 8:32 AM, "Clint Byrum" <cl...@fewbar.com> wrote: > > > > Excerpts from Lee, Alexis's message of 2014-11-05 15:46:43 +0100: > > > I'm considering adding a function which takes a list and returns the > first > > > non-null, non-empty value in that list. > > > > > > So you could do EG: > > > > > > some_thing: > > > config: > > > ControlVIP: > > > first_nonnull: > > > - {get_param: ControlVIP} > > > - {get_attr: [ControlVirtualIP, fixed_ips, 0, > ip_address]}]} > > > > > > I'm open to other names, EG "some", "or", "fallback_list" etc. > > > > > > Steve Hardy suggested building this into get_attr or Fn::Select. My > feeling > > > is that those each do one job well right now, I'm happy to take a steer > > > though. > > > > > > What do you think please? > > > > > > > Yes this is super useful for writing responsive, reusable templates. > > > > I'd like to suggest that this be called 'coalesce' as that is what SQL > > calls it. > > Although I have no clue why they called it that (colalesce mean join/merge > not get first non-null). I'd rather it be called what it does > "first_nonnull()" seems more obvious to me. We could also try the > conditional as Zane suggested.
I believe it is called that because it is meant to coalesce a list of variables in descending priority into one, which is precisely the use case presented. That said, first_nonnull is fine too if that nuance is not as obvious to others as it is to me. :-P _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev