[openstack-dev] [Fuel] Changing APIs and API versioning

Maciej Kwiek mkwiek at mirantis.com
Tue Nov 24 08:01:46 UTC 2015


Vitaly,

That's great news. I agree that we need to run fuelclient against every
change in nailgun, but on the other hand - I think we should stick to the
protocol that Igor proposed:

* Announce this change in openstack-dev ML.
* Wait 1 week before approving it, so anyone can prepare.
* Change author has to work with QA in order make sure they are
prepared for this change.

Because some people we may not be aware of can rely on our API behaving in
the way it usually behaves :).

Regards,
Maciej

On Mon, Nov 23, 2015 at 5:46 PM, Vitaly Kramskikh <vkramskikh at mirantis.com>
wrote:

> Roman,
>
> Sorry for breaking all the stuff again. I've got suggestion to change this
> from one of the core reviewers.
>
> Fortunately, separation of Fuel UI is already in progress (Vladimir
> Kozhukalov may want to provide extra info here), but it won't guarantee
> protection from similar issues in future. What we really need is to run
> fuelclient functional tests against every change in nailgun.
>
> 2015-11-23 22:56 GMT+07:00 Roman Prykhodchenko <me at romcheg.me>:
>
>> Folks.
>>
>> This happened again. Nailgun’s API was silently changed [1] breaking
>> python-fuelclient and everything else that was relying on it.
>>
>> I feel like this is the point when just discussing the issue is not
>> enough so I call for a vote: Let’s separate Nailgun from Fuel UI and put
>> them into different repositories now.
>>
>> Please cast your votes (either +1 or -1) to this thread. You can also
>> provide your reasoning and more thoughts.
>>
>>
>> - romcheg
>>
>>
>> 1. https://review.openstack.org/#/c/240234/
>>
>> 26 жовт. 2015 р. о 11:11 Sebastian Kalinowski <skalinowski at mirantis.com>
>> написав(ла):
>>
>> 2015-10-23 11:36 GMT+02:00 Igor Kalnitsky <ikalnitsky at mirantis.com>:
>>
>>> Roman, Vitaly,
>>>
>>> You're both saying right things, and you guys bring a sore topic up
>>> again.
>>>
>>> The thing is that Nailgun's API isn't the best one.. but we're trying
>>> to improve it step-by-step, from release to release. We have so many
>>> things to reconsider and to fix that it'd require a huge effort to
>>> make backward compatible changes and support it. So we decided ignore
>>> backward compatibility for clients for awhile and consider our API as
>>> unstable.
>>>
>>> I agree with Roman that such changes must not be made secretly, and we
>>> should at least announce about them. Moreover, every core must think
>>> about consequences before approving them.
>>>
>>> So I propose to do the following things when backward incompatible
>>> change to API is required:
>>>
>>> * Announce this change in openstack-dev ML.
>>> * Wait 1 week before approving it, so anyone can prepare.
>>> * Change author has to work with QA in order make sure they are
>>> prepared for this change.
>>>
>>> Any thoughts?
>>>
>>
>>
>> +1.
>>
>> Although there is one thing that you didn't mention (but probably
>> everyone know about it)
>> is to solve the issue with fuelclient not beign tested against changes in
>> nailgun.
>> We need not only run it for every change in nailgun (or for only those
>> that touch files under "api"
>> dir) but also cover more endpoints with fuelclient tests against real
>> API, not mocks, to discover
>> such issues earlier.
>>
>>
>>>
>>> Thanks,
>>> Igor
>>>
>>> On Wed, Oct 21, 2015 at 5:24 PM, Vitaly Kramskikh
>>> <vkramskikh at mirantis.com> wrote:
>>> > JFYI: (re-)start of this discussion was instigated by merge of this
>>> change
>>> > (and here is revert).
>>> >
>>> > And this is actually not the first time when we make backward
>>> incompatible
>>> > changes in our API. AFAIR, the last time it was also about the network
>>> > configuration handler. We decided not to consider our API frozen, make
>>> the
>>> > changes and break backward compatibility. So now is the time to
>>> reconsider
>>> > this.
>>> >
>>> > API backward compatibility is a must for good software, but we also
>>> need to
>>> > understand that introducing API versioning is not that easy and will
>>> > increase efforts needed to make new changes in nailgun.
>>> >
>>> > I'd go this way:
>>> >
>>> > Estimate the priority of introducing API versioning - maybe we have
>>> other
>>> > things we should invest our resources to
>>> > Estimate all the disadvantages this decision might have
>>> > Fix all the issues in the current API (like this one)
>>> > Implement API versioning support (yes, we don't have this mechanism
>>> yet, so
>>> > we can't just "bump API version" like Sergii suggested in another
>>> thread)
>>> > Consider the current API as frozen v1, so backward incompatible
>>> changes (or
>>> > maybe all the changes?) should go to v2
>>> >
>>> >
>>> > 2015-10-21 20:25 GMT+07:00 Roman Prykhodchenko <me at romcheg.me>:
>>> >>
>>> >> Hi folks,
>>> >>
>>> >> I’d like to touch the aspect of Fuel development process that seems
>>> to be
>>> >> as wrong as possible. That aspect is how we change the API.
>>> >>
>>> >> The issue is that in Fuel anyone can change API at any point of time
>>> >> without even warning the rest of the same component’s team. Relying
>>> on this
>>> >> kind of API is basically impossible. We constantly have problems when
>>> even
>>> >> components of Fuel stop working due to unexpected changes in the API.
>>> >> Thinking about another software that must be integrated with Fuel is
>>> hardly
>>> >> possible with the current approach.
>>> >>
>>> >> As for a grown-up project there is a strong need for Fuel in general
>>> and
>>> >> for Nailgun in particular to work on a policy for making changes to
>>> their
>>> >> APIs. Living in OpenStack ecosystem we must at least take a look how
>>> it’s
>>> >> done in its components and try to do something similar. After working
>>> with
>>> >> Nova, Keystone, Ironic and other components I would propose to start
>>> with
>>> >> the following: let’s not make any changes to the API. Instead, let’s
>>> create
>>> >> a new version of Nailgun’s API that will appear in Fuel 8.0 and make
>>> all the
>>> >> changes there. That is the thing that will instantaneously make lives
>>> of
>>> >> other components much easier, if we make it now.
>>> >>
>>> >> After doing the essential part let’s think about how we are going to
>>> live
>>> >> with that in the future. There are several APIs in Fuel, the rest of
>>> the
>>> >> email is only touching Nailgun’s REST API. I can see the things
>>> somehow like
>>> >> the following:
>>> >>
>>> >>  - Introduce API documentation by embedding Swagger and Swagger UI.
>>> >>    The current approach when we leave API docs for documentation team
>>> is
>>> >> not effective. Swagger generates the documentation and resolves this
>>> issue.
>>> >>  - After releasing a version of Fuel, it’s API is called stable and
>>> frozen
>>> >> for any changes, unless they allign API to the documentation or
>>> >> documentation to the API.
>>> >>  - All changes to a stable APIs must be backported to the stable
>>> version
>>> >> of Fuel that introduced the corresponding API.
>>> >>  - In order to guarantee that a stable API is not changed, Jenkins
>>> jobs
>>> >> should make automatic checks for every new patch set
>>> >>
>>> >> Details about all the above mentioned proposals can be discussed in
>>> >> separate threads so this one will stay uncluttered. I'd like to also
>>> summon
>>> >> those OpenStack folks, who tried to resolve the same issue and ask
>>> them
>>> >> about any common solutions in the ecosystem.
>>> >>
>>> >>
>>> >> - romcheg
>>> >>
>>> >>
>>> >>
>>> >>
>>> >>
>>> >>
>>> __________________________________________________________________________
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>>> >>
>>> >
>>> >
>>> >
>>> > --
>>> > Vitaly Kramskikh,
>>> > Fuel UI Tech Lead,
>>> > Mirantis, Inc.
>>> >
>>> >
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>
>
> --
> Vitaly Kramskikh,
> Fuel UI Tech Lead,
> Mirantis, Inc.
>
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