[openstack-dev] [nova][api] New micro-version needed for api bug fix or not?

John Garbutt john at johngarbutt.com
Mon Jun 1 11:31:00 UTC 2015

On 29 May 2015 at 19:58, Jay Pipes <jaypipes at gmail.com> wrote:
> On 05/29/2015 05:04 AM, John Garbutt wrote:
>> On 29 May 2015 at 09:00, Sahid Orentino Ferdjaoui
>> <sahid.ferdjaoui at redhat.com> wrote:
>>> On Fri, May 29, 2015 at 08:47:01AM +0200, Jens Rosenboom wrote:
>>>> As the discussion in https://review.openstack.org/179569 still
>>>> continues about whether this is "just" a bug fix, or an API change
>>>> that will need a new micro version, maybe it makes sense to take this
>>>> issue over here to the ML.
>>> Changing version of the API probably makes sense also for bug if it
>>> changes the behavior of a command/option to something backward
>>> incompatible. I do not believe it is the case for your change.
>>>> My personal opinion is undecided, I can see either option as being
>>>> valid, but maybe after having this open bug for four weeks now we can
>>>> come to some conclusion either way.
>> Apologies for this, we are still trying to evolve the rules for when
>> to bump the API micro versions, there will be some pain while we work
>> that out :(
>>  From the summit discussion, I think got three things roughly agreed
>> (although we have not yet got them written up into a devref document,
>> to make the formal agreement, and we need to do that ASAP):
>> 1)
>> We agreed changing a 500 error to an existing error (or making it
>> succeed in the usual way) is a change that doesn't need a version
>> bump, its a bug fix.
>> 2)
>> We also agreed that all micro version bumps need a spec, to help avoid
>> is adding more "bad" things to the API as we try and move forward.
>> This is heavy weight. In time, we might find certain "good" patterns
>> where we want to relax that restriction, but we haven't done enough
>> changes to agree on those patterns yet. This will mean we are moving a
>> bit slower at first, but it feels like the right trade off against
>> releasing (i.e. something that lands in any commit on master) an API
>> with a massive bug we have to support for a long time.
>> 3)
>> Discuss other cases as they came up, and evolve the plans based on the
>> examples that come up, with a focus on bumping the version being
>> (almost) free, and useful for clients to work out what has changed.
>> Is that how everyone else remembers that discussion?
> Yes.
>> Now when it comes to your change. It is a bug in the default policy.
>> Sadly this policy is also quite hard wired to admin vs non-admin. We
>> still need work to make policy more discoverable, so I don't think we
>> need to make this any more discoverable as such.
>> Having said all that, we probably need to look at this case more
>> carefully, after your patch has merged, and work out how this should
>> work now we assuming strong validation, and granular policy, etc.
> Actually, after reading the IRC conversation between Dims and Sean, I
> believe Sean is right to want a microversion bump for this patch. If two
> clouds are deployed, one with this patch and another without, a client
> issuing commands to both will have no idea whether the ip6 filter will be
> considered or not. Having a microversion increment in the patch would allow
> clients to request behaviour they want (the ip6 filter).

Ah, true.

If the cloud that ignored the ip6 filter actually had errored out when
given an ip6 filter, it would be very different. But you are right, it
silently ignores the param, which can lead to confusion, so its
probably best to bump the version.


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