How do these plans fit with the idea of creating a unified client library (either as one package or several, based on a common core)?
On Mon, Jun 18, 2012 at 5:11 PM, Monty Taylor <mord...@inaugust.com> 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 > > _______________________________________________ > Mailing list: https://launchpad.net/~openstack > Post to : openst...@lists.launchpad.net > Unsubscribe : https://launchpad.net/~openstack > More help : https://help.launchpad.net/ListHelp >
_______________________________________________ Mailing list: https://launchpad.net/~openstack-poc Post to : openstack-poc@lists.launchpad.net Unsubscribe : https://launchpad.net/~openstack-poc More help : https://help.launchpad.net/ListHelp
