I think I'll look into a version of (2). The difference being that I think using an int is too large of a range and provides unnecessary granularity. If two strategies or providers both have snapshot strategies, they are both simply going to return the max int. However, if we use an enum with values like:
HIGHEST, PLUGIN, HYPERVISOR, DEFAULT and NO, (HIGHEST would be reserved for unforeseen future use, testing, simulators, etc.) then we allow strategies and providers to fall in the same bucket. All strategies and providers would be sorted and asked to handle operations in that order. Ultimately, this requires that plugins do their best to determine whether they can actually handle an operation, because if two say they can, there is no way for the MS to intelligently choose between the two. -- Chris Suich chris.su...@netapp.com NetApp Software Engineer Data Center Platforms – Cloud Solutions Citrix, Cisco & Red Hat On Oct 4, 2013, at 6:10 PM, Darren Shepherd <darren.s.sheph...@gmail.com> wrote: > Sure, I'm open to suggestions. Basically I think we've discussed > > 1) Global Setting > 2) canHandle() returns an int > 3) Strategy has an enum type assigned > > I'm open to all three, I don't have much vested interest in this. > > Darren > > On Fri, Oct 4, 2013 at 3:00 PM, SuichII, Christopher > <chris.su...@netapp.com> wrote: >> Well, it seems OK, but I think we should keep on discussing our options. One >> concern I have with the global config approach is that it adds manual steps >> for 'installing' extensions. Each extension must have installation >> instructions to indicate which global configurations it must be included in >> and where in that list it should be put (and of course, many extension are >> going to say that they should be at the front of the list). >> >> -Chris >> -- >> Chris Suich >> chris.su...@netapp.com >> NetApp Software Engineer >> Data Center Platforms – Cloud Solutions >> Citrix, Cisco & Red Hat >> >> On Oct 4, 2013, at 12:12 PM, Darren Shepherd <darren.s.sheph...@gmail.com> >> wrote: >> >>> On 10/04/2013 11:58 AM, SuichII, Christopher wrote: >>>> Darren, >>>> >>>> I think one of the benefits of allowing the priority to be specified in >>>> the xml is that it can be configured after deployment. If for some reason >>>> two strategies or providers conflict, then their priorities can be changed >>>> in XML to resolve the conflict. I believe the Spring @Order annotation an >>>> be specified in XML, not just as an annotation. >>>> >>>> -Chris >>>> >>> >>> I would *prefer* extensions to be order independent, but if we determine >>> they are order dependant, then that is fine too. So if we conclude that >>> the simplest way to address this is to order the Strategies based on >>> configuration, then I will add an ordering "global configuration" as >>> described at >>> https://cwiki.apache.org/confluence/display/CLOUDSTACK/Extensions. >>> >>> Does the order configuration setting approach seem fine? >>> >>> Darren >>
