On Tue, Nov 20, 2012 at 10:40:58AM -0500, Russell Bryant wrote: > Greetings, > > There is currently a patch in the review queue for nova that adds hooks. > > https://review.openstack.org/#/c/16336/ > > I like the concept, but I think it could benefit from some design > discussion. That's difficult on gerrit and much better suited for the > mailing list, so here we are. My thoughts are - What is the intended usage of the hooks? - What is the usage relationship between hooks & extensions ? - What are they expected to be allowed to do / not do ? - What guarantees are provided wrt hooks continuing to work minor, and major updates ? - What internal APIs (if any) should hooks be allowed to use ? - Is there any way to enforce any rules we make above ? My overriding desire is that we want to avoid sleep-walking into a situation where people write all sorts of hooks; these rely on internal code we consider unstable; we're then forced to maintain stabilty of internal APIs across major and/or minor updates to avoid breaking people's hooks. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|