Additionally, can anyone here summarize the current status of v3 documentation? Is there a process I can currently run against Nova to generate a WADL (I want to make sure the Pecan changes work with it)?
--- Ryan Petrello Senior Developer, DreamHost ryan.petre...@dreamhost.com On Dec 18, 2013, at 9:46 AM, Ryan Petrello <ryan.petre...@dreamhost.com> wrote: > Sounds like what I’m hearing is “Let’s see something that uses this (that > works)”? I’ll work on that :) > > --- > Ryan Petrello > Senior Developer, DreamHost > ryan.petre...@dreamhost.com > > On Dec 18, 2013, at 9:45 AM, Ryan Petrello <ryan.petre...@dreamhost.com> > wrote: > >> Jamie: >> >> Your approach makes sense, but it still uses both pecan and Routes. One of >> the goals of my patch was to (eventually) be able to remove the use of >> Routes entirely in v3 for Nova once all of the extensions are re-implemented >> with pecan (so that we’re not defining a mix of object dispatch and >> regular-expression style routes). >> >> --- >> Ryan Petrello >> Senior Developer, DreamHost >> ryan.petre...@dreamhost.com >> >> On Dec 18, 2013, at 6:05 AM, Jamie Lennox <jamielen...@redhat.com> wrote: >> >>> I attempted this in keystone as part of a very simple extension [1]. I >>> understand that it is a much simpler case but nesting the Pecan within the >>> existing routing infrastructure, rather than have a single Pecan app was >>> fairly simple (though there are some limiting situations). >>> >>> Any reason you decided to go this way rather than the one in my review? >>> >>> [1] https://review.openstack.org/#/c/62810/ >>> >>> ----- Original Message ----- >>>> From: "Ryan Petrello" <ryan.petre...@dreamhost.com> >>>> To: "OpenStack Development Mailing List (not for usage questions)" >>>> <openstack-dev@lists.openstack.org> >>>> Sent: Wednesday, 18 December, 2013 7:08:09 AM >>>> Subject: Re: [openstack-dev] [Nova] Support for Pecan in Nova >>>> >>>> So any additional feedback on this patch? I’d love to start working on >>>> porting some of the other extensions to pecan, but want to make sure I’ve >>>> got approval on this approach first. >>>> >>>> https://review.openstack.org/#/c/61303/7 >>>> >>>> --- >>>> Ryan Petrello >>>> Senior Developer, DreamHost >>>> ryan.petre...@dreamhost.com >>>> >>>> On Dec 14, 2013, at 10:45 AM, Doug Hellmann <doug.hellm...@dreamhost.com> >>>> wrote: >>>> >>>>> >>>>> >>>>> >>>>> On Sat, Dec 14, 2013 at 7:55 AM, Christopher Yeoh <cbky...@gmail.com> >>>>> wrote: >>>>> >>>>> On Sat, Dec 14, 2013 at 8:48 AM, Doug Hellmann >>>>> <doug.hellm...@dreamhost.com> wrote: >>>>> That covers routes. What about the properties of the inputs and outputs? >>>>> >>>>> >>>>> I think the best way for me to describe it is that as the V3 API core and >>>>> all the extensions >>>>> are written, both the routes and input and output parameters are from a >>>>> client's perspective fixed at application >>>>> startup time. Its not an inherent restriction of the framework (an >>>>> extension could for >>>>> example dynamically load another extension at runtime if it really wanted >>>>> to), but we just don't do that. >>>>> >>>>> OK, good. >>>>> >>>>> >>>>> >>>>> Note that values of parameters returned can be changed by an extension >>>>> though. For example os-hide-server-addresses >>>>> can based on a runtime policy check and the vm_state of the server, filter >>>>> whether the values in the >>>>> addresses field are filtered out or not when returning information about a >>>>> server. This isn't a new thing in the >>>>> V3 API though, it already existed in the V2 API. >>>>> >>>>> OK, it seems like as long as the fields are still present that makes the >>>>> API at least consistent for a given deployment's configuration. >>>>> >>>>> Doug >>>>> >>>>> >>>>> >>>>> Chris >>>>> >>>>> >>>>> On Fri, Dec 13, 2013 at 4:43 PM, Ryan Petrello >>>>> <ryan.petre...@dreamhost.com> wrote: >>>>> Unless there’s some other trickiness going on that I’m unaware of, the >>>>> routes for the WSGI app are defined at application startup time (by >>>>> methods called in the WSGI app’s __init__). >>>>> >>>>> --- >>>>> Ryan Petrello >>>>> Senior Developer, DreamHost >>>>> ryan.petre...@dreamhost.com >>>>> >>>>> On Dec 13, 2013, at 12:56 PM, Doug Hellmann <doug.hellm...@dreamhost.com> >>>>> wrote: >>>>> >>>>>> >>>>>> >>>>>> >>>>>> On Thu, Dec 12, 2013 at 9:22 PM, Christopher Yeoh <cbky...@gmail.com> >>>>>> wrote: >>>>>> On Fri, Dec 13, 2013 at 4:12 AM, Jay Pipes <jaypi...@gmail.com> wrote: >>>>>> On 12/11/2013 11:47 PM, Mike Perez wrote: >>>>>> On 10:06 Thu 12 Dec , Christopher Yeoh wrote: >>>>>> On Thu, Dec 12, 2013 at 8:59 AM, Doug Hellmann >>>>>> <doug.hellm...@dreamhost.com >>>>>> <mailto:doug.hellm...@dreamhost.com>>wrote: >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> On Wed, Dec 11, 2013 at 3:41 PM, Ryan Petrello < >>>>>> ryan.petre...@dreamhost.com >>>>>> <mailto:ryan.petre...@dreamhost.com>> >>>>>> wrote: >>>>>> >>>>>> Hello, >>>>>> >>>>>> I’ve spent the past week experimenting with using Pecan for >>>>>> Nova’s >>>>>> API >>>>>> and have opened an experimental review: >>>>>> >>>>>> >>>>>> https://review.openstack.org/#/c/61303/6 >>>>>> >>>>>> …which implements the `versions` v3 endpoint using pecan (and >>>>>> paves the >>>>>> way for other extensions to use pecan). This is a *potential* >>>>>> >>>>>> approach >>>>>> I've considered for gradually moving the V3 API, but I’m open >>>>>> to other suggestions (and feedback on this approach). I’ve >>>>>> also got a few open questions/general observations: >>>>>> >>>>>> 1. It looks like the Nova v3 API is composed *entirely* of >>>>>> extensions (including “core” API calls), and that extensions >>>>>> and their routes are discoverable and extensible via installed >>>>>> software that registers >>>>>> itself >>>>>> via stevedore. This seems to lead to an API that’s composed of >>>>>> >>>>>> installed >>>>>> software, which in my opinion, makes it fairly hard to map out >>>>>> the >>>>>> API (as >>>>>> opposed to how routes are manually defined in other WSGI >>>>>> frameworks). I >>>>>> assume at this time, this design decision has already been >>>>>> solidified for >>>>>> v3? >>>>>> >>>>>> >>>>>> Yeah, I brought this up at the summit. I am still having some >>>>>> trouble understanding how we are going to express a stable core >>>>>> API for compatibility testing if the behavior of the API can be >>>>>> varied so significantly by deployment decisions. Will we just >>>>>> list each >>>>>> "required" >>>>>> extension, and forbid any extras for a compliant cloud? >>>>>> >>>>>> >>>>>> Maybe the issue is caused by me misunderstanding the term >>>>>> "extension," which (to me) implies an optional component but is >>>>>> perhaps reflecting a technical implementation detail instead? >>>>>> >>>>>> >>>>>> Yes and no :-) As Ryan mentions, all API code is a plugin in the V3 >>>>>> API. However, some must be loaded or the V3 API refuses to start >>>>>> up. In nova/api/openstack/__init__.py we have >>>>>> API_V3_CORE_EXTENSIONS which hard codes which extensions must be >>>>>> loaded and there is no config option to override this (blacklisting >>>>>> a core plugin will result in the V3 API not starting up). >>>>>> >>>>>> So for compatibility testing I think what will probably happen is >>>>>> that we'll be defining a minimum set (API_V3_CORE_EXTENSIONS) that >>>>>> must be implemented and clients can rely on that always being >>>>>> present >>>>>> on a compliant cloud. But clients can also then query through >>>>>> /extensions what other functionality (which is backwards compatible >>>>>> with respect to core) may also be present on that specific cloud. >>>>>> >>>>>> This really seems similar to the idea of having a router class, some >>>>>> controllers and you map them. From my observation at the summit, >>>>>> calling everything an extension creates confusion. An extension >>>>>> "extends" something. For example, Chrome has extensions, and they >>>>>> extend the idea of the core features of a browser. If you want to do >>>>>> more than back/forward, go to an address, stop, etc, that's an >>>>>> extension. If you want it to play an audio clip "stop, hammer time" >>>>>> after clicking the stop button, that's an example of an extension. >>>>>> >>>>>> In OpenStack, we use extensions to extend core. Core are the >>>>>> essential feature(s) of the project. In Cinder for example, core is >>>>>> volume. In core you can create a volume, delete a volume, attach a >>>>>> volume, detach a volume, etc. If you want to go beyond that, that's >>>>>> an extension. If you want to do volume encryption, that's an example >>>>>> of an extension. >>>>>> >>>>>> I'm worried by the discrepancies this will create among the programs. >>>>>> You mentioned maintainability being a plus for this. I don't think >>>>>> it'll be great from the deployers perspective when you have one >>>>>> program that thinks everything is an extension and some of them have >>>>>> to be enabled that the deployer has to be mindful of, while the rest >>>>>> of the programs consider all extensions to be optional. >>>>>> >>>>>> +1. I agree with most of what Mike says above. The idea that there are >>>>>> core "extensions" in Nova's v3 API doesn't make a whole lot of sense to >>>>>> me. >>>>>> >>>>>> >>>>>> So would it help if we used the term "plugin" to talk about the framework >>>>>> that the API is implemented with, >>>>>> and extensions when talking about things which extend the core API? So >>>>>> the whole of the API is implemented >>>>>> using plugins, while the core plugins are not considered to be >>>>>> extensions. >>>>>> >>>>>> That distinction does help. >>>>>> >>>>>> Are the extensions enabled at startup time, or at runtime when an API >>>>>> call is made? That is, could 2 different users of the same cloud service >>>>>> instance see different fields in the value returned from the call >>>>>> because of some runtime decision made inside either an extension (where >>>>>> the extension might not add fields for some reason) or a bit of core >>>>>> code (by deciding not to call an extension at all)? >>>>>> >>>>>> Doug >>>>>> _______________________________________________ >>>>>> OpenStack-dev mailing list >>>>>> OpenStack-dev@lists.openstack.org >>>>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>>>> >>>>> >>>>> _______________________________________________ >>>>> OpenStack-dev mailing list >>>>> OpenStack-dev@lists.openstack.org >>>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>>>> >>>>> >>>>> _______________________________________________ >>>>> OpenStack-dev mailing list >>>>> OpenStack-dev@lists.openstack.org >>>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> OpenStack-dev mailing list >>>>> OpenStack-dev@lists.openstack.org >>>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>>>> >>>>> >>>>> _______________________________________________ >>>>> OpenStack-dev mailing list >>>>> OpenStack-dev@lists.openstack.org >>>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>>> >>>> >>>> _______________________________________________ >>>> OpenStack-dev mailing list >>>> OpenStack-dev@lists.openstack.org >>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>>> >>> >>> _______________________________________________ >>> OpenStack-dev mailing list >>> OpenStack-dev@lists.openstack.org >>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >> > > > _______________________________________________ > OpenStack-dev mailing list > OpenStack-dev@lists.openstack.org > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
