[openstack-dev] [nova] Future of the Nova API

Christopher Yeoh cbkyeoh at gmail.com
Sun Mar 2 03:13:13 UTC 2014

Hi Steve,

On Sat, 1 Mar 2014 16:14:19 -0500 (EST)
Steve Gordon <sgordon at redhat.com> wrote:

> That said I am still under the perhaps misguided impression that
> implementing tasks on v2 would not be *completely* impossible -
> smarter people than me have debated and will no doubt continue to
> debate how practical/reasonable that would really be and the relevant
> compromises to the design though.

Heh, this is software, nothing is *completely* impossible :-) It does
as you say come down to the design and short as well as long
term maintenance tradeoffs. And most API/library based projects have to
eventually make these sorts of decisions . Eg. when to make major
versioning decisions and even if they do, whether they try to backport
features to earlier versions. 

> My feeling both with my product hat and my upstream documentation
> contributor hat on knowing some of the issues we've had there in the
> past is that one release cycle of deprecation for v2 would not be
> enough notice for this kind of change, particularly if it's also a
> cycle where v3 is still being pretty actively worked on and a moving
> target for the rest of the ecosystem (which it looks like will be the
> case for Juno, if we continue in the direction of doing v3).

Thank you to you and everyone else for their feedback around this. With
the exception of XML deprecation I don't think anyone was considering a
single cycle for deprecation for V2 would be reasonable. But numbers
around how long would be reasonable would be helpful to guide as to
what path we take.

I would be interested in your opinion on the impact of a V2 version
release which had backwards incompatibility in only one area - and
that is input validation. So only apps/SDKs which are currently misusing
the API (I think the most common problem would be sending extraneous
data which is currently ignored) would be adversely affected. Other
cases where where the API was used correctly would be unaffected.

In this kind of scenario would we need to maintain the older V2 version
where there is poor input validation as long? Or would the V2 version
with strong input validation be sufficient? 


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