[Openstack] [Openstack-poc] Thoughts on client library releasing

Gabriel Hurley Gabriel.Hurley at nebula.com
Tue Jun 19 00:20:03 UTC 2012


Big +1 for automated tagging and releasing (sounds like we're managing wildlife...) from Jenkins!

    - Gabriel

> -----Original Message-----
> From: openstack-bounces+gabriel.hurley=nebula.com at lists.launchpad.net
> [mailto:openstack-
> bounces+gabriel.hurley=nebula.com at lists.launchpad.net] On Behalf Of
> Monty Taylor
> Sent: Monday, June 18, 2012 3:00 PM
> To: Joe Heck
> Cc: openstack-poc at lists.launchpad.net; openstack at lists.launchpad.net
> Subject: Re: [Openstack] [Openstack-poc] Thoughts on client library releasing
> 
> 
> 
> On 06/18/2012 02:26 PM, Joe Heck wrote:
> > Monty -
> >
> > Thierry stated it as an assumption last PPB meeting, but I'd like it
> > to be explicit that we have at least a tag on each client library
> > release that we make so that it's possible to distribute a version of
> > the clients.
> 
> +1000
> 
> I didn't want to get too far into implementation details, but the way I'd really
> like to see this work for the client libs is that releases are actually trigger via
> jenkins by tags on the repo - so there would literally be no way to release
> something _without_ a tag.
> 
> I've got a POC patch to do the tag-based-versioning here:
> 
> https://review.openstack.org/#/c/8427/
> 
> We need to get (aiui) one thing landed to zuul so that we can appropriately
> trigger on tag events... but that's the plan in my brain hole.
> 
> > On Jun 18, 2012, at 2:11 PM, Monty Taylor wrote:
> >> We're trying to figure out how we release client libraries. We're
> >> really close - but there are some sticking points.
> >>
> >> First of all, things that don't really have dissent (with
> >> reasoning)
> >>
> >> - We should release client libs to PyPI
> >>
> >> Client libs are for use in other python things, so they should be
> >> able to be listed as dependencies. Additionally, proper releases to
> >> PyPI will make our cross project depends work more sensibly
> >>
> >> - They should not necessarily be tied to server releases
> >>
> >> There could be a whole version of the server which sees no needed
> >> changes in the client. Alternately, there could be new upcoming
> >> server features which need to go into a released version of the
> >> library even before the server is released.
> >>
> >> - They should not be versioned with the server
> >>
> >> See above.
> >>
> >> - Releases of client libs should support all published versions of
> >> server APIs
> >>
> >> An end user wants to talk to his openstack cloud - not necessarily to
> >> his Essex cloud or his Folsom cloud. That user may also have accounts
> >> on multiple providers, and would like to be able to write one program
> >> to interact with all of them - if the user needed the folsom version
> >> of the client lib to talk to the folsom cloud and the essex version
> >> to talk to the essex cloud, his life is very hard. However, if he can
> >> grab the latest client lib and it will talk to both folsom and essex,
> >> then he will be happy.
> >>
> >> There are three major points where there is a lack of clear
> >> agreement. Here they are, along with suggestions for what we do about
> >> them.
> >>
> >> - need for "official" stable branches
> >>
> >> I would like to defer on this until such a time as we actually need
> >> it, rather than doing the engineering for in case we need it. But
> >> first, I'd like to define we, and that is that "we" are OpenStack as
> >> an upstream. As a project, we are at the moment probably the single
> >> friendliest project for the distros in the history of software. But
> >> that's not really our job. Most people out there writing libraries do
> >> not have multiple parallel releases of those libraries - they have
> >> the stable library, and then they release a new one, and people
> >> either upgrade their apps to use the new lib or they don't.
> >>
> >> One of the reasons this has been brought up as a need is to allow for
> >> drastic re-writes of a library. I'll talk about that in a second, but
> >> I think that is a thing that needs to have allowances for happening.
> >>
> >> So the model that keystone-lite used - create an experimental branch
> >> for the new work, eventually propose that it becomes the new master -
> >> seems like a better fit for the "drastic rewrite" scenario than
> >> copying the stable/* model from the server projects, because I think
> >> the most common thing will be that library changes are evolutionary,
> >> and having two mildly different branches that both represent
> >> something that's actually pretty much stable will just be more
> >> confusing than helpful.
> >>
> >> That being said - at such a time that there is actually a pain-point
> >> or a specific need for a stable branch, creating branches is fairly
> >> easy ... but I think once we have an actual burning need for such a
> >> thing, it will make it easier for us to look at models of how we'll
> >> use it.
> >>
> >> - API or major-rewrite-driven versioning scheme
> >>
> >> I was wondering why bcwaldon and I were missing each other so
> >> strongly in the channel the other day when we were discussing this,
> >> and then I realized that it's because we have one word "API" that's
> >> getting overloaded for a couple of different meanings - and also that
> >> I was being vague in my usage of the word. So to clarify, a client
> >> library has:
> >>
> >> * programming level code APIs * supported server REST APIs
> >>
> >> So I back off everything I said about tying client libs version to
> >> server REST API support. Brian was right, I was wrong. The thing
> >> that's more important here is that the version should indicate
> >> programmer contract, and if it that is changed in a breaking manner,
> >> the major number should bump.
> >>
> >> If we combine that with the point from above that our libraries
> >> should always support the existing server REST APIs, then I think we
> >> can just purely have statements like "support for compute v3 can be
> >> found in 2.7.8 and later" and people will likely be fine, because it
> >> will map easily to the idea "just grab the latest lib and you should
> >> be able to talk to the latest server" Yea?
> >>
> >> So in that case, the client libs versions are purely whatever they
> >> are right now, and we'll increase them moving forward using normal
> >> library version thoughts.
> >>
> >> - room for deprecating old APIs
> >>
> >> The above then leads us to wanting to know what we do about supported
> >> server REST APIs over time, especially since I keep making sweeping
> >> statements about "should support all available server versions" ...
> >> How about this as a straw man: Since we're planning on beginning to
> >> run tests of the client libs against previous versions (so we'll test
> >> trunk novaclient against essex nova in addition to trunk nova) ... we
> >> need support for past versions of servers as long as our automation
> >> can sensibly spin up a past version. (Since the support for that API
> >> version shouldn't need huge amounts of work moving forward) But there
> >> will reach a point where old server versions require stuff that's
> >> older than we feel like supporting, and at that point we drop it.
> >> (or, more to the point, that we reserve the right in the future to
> >> declare that we're going to drop old server API versions - but the
> >> general policy is that we'll keep old support until it becomes a pain
> >> in the ass)
> >>
> >> Does that all sit well with folks?
> >>
> >> Monty
> >>
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> >
> >
> >
> 
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