Open Stack

On Tue, Jul 28, 2015 at 1:57 PM Jim Rollenhagen <jim at jimrollenhagen.com>
wrote:

> On Tue, Jul 28, 2015 at 08:23:34PM +0000, Devananda van der Veen wrote:
> > On Mon, Jul 27, 2015 at 4:58 PM Sean Dague <sean at dague.net> wrote:
> >
> > > On 07/27/2015 07:10 PM, Jim Rollenhagen wrote:
> > > > On Mon, Jul 27, 2015 at 03:28:49PM -0700, Clint Byrum wrote:
> > > >> Excerpts from Sean Dague's message of 2015-07-27 13:41:20 -0700:
> > > >>> So the CLI should actually break less often, and will expose the
> most
> > > >>> functionality you can get out of your cloud.
> > > >>>
> > > >>
> > > >> What I find odd about this is that I want the CLI to be a faithful
> > > >> representation of the API, because many times the CLI is the only
> way I
> > > >> can access the API for integration purposes.
> > > >
> > > > "Faithful representation of the API" is an interesting way to put
> it; it
> > > > is a "faithful representation" either way. This way is a
> representation
> > > > of the newest state of the API. It sounds like you're expecting a
> > > > representation of the oldest state, or the state that you're used to
> > > > (the hardest to predict).
> > > >
> > > >>
> > > >> So lets say I just want a very simple bash script to do something
> with
> > > >> nodes:
> > > >>
> > > >> id=$(ironic node-create ...|getid)
> > > >> while true ; do
> > > >>   state=$(ironic node-get $id | get_state)
> > > >>   case $state in
> > > >>   AVAILABLE)
> > > >>     break;;
> > > >>   ERROR)
> > > >>     # retry or something
> > > >>     ;;
> > > >>   *)
> > > >>     splode("UNKNOWN STATE")
> > > >>     ;;
> > > >>   esac
> > > >> done
> > > >>
> > > >> Then the script is going to start exploding with a CLI that shows me
> > > >> ENROLL state.
> > > >>
> > > >> So I'm not sure having the CLI go faster than the python client is a
> > > >> great way to avoid breakage. It might be the opposite of that, and
> that
> > > >> might just be a large burden on users.
> > > >
> > > > I tend to think that folks using the CLI for automation should be
> > > > pinning the version in that automation. A quick
> IRONIC_API_VERSION=1.8
> > > > or whatever would solve this problem. When new versions are
> available,
> > > > read the notes for that version and adjust your code as necessary. Or
> > > > just leave it at the same version until it breaks. :)
> > >
> > > Yeh, it's a cli, not a bash API. Having had to maintain devstack
> > > exercise code for a while, I'll tell you that the above is just a time
> > > bomb waiting to go off. None of the CLIs have that kind of contract,
> nor
> > > should they. Inflicting the bad UX of today on future generations
> > > because someone thinks, incorrectly, that it's a bash SDK is not a good
> > > trade off.
> > >
> > >
> > And people script against that CLI all. the. time.
> >
> > Is it pretty? No. But is it something that people do? Yep.
> >
> > Does that mean we should try to care? Yea, I think so, and I think that
> > means we should try to avoid breaking it when reasonably possible.
> >
> >
> > > If you want to pin things, explicitly, like jroll said, do that. And
> > > microversions lets you until your clouds uplift past your legacy code.
> > >
> >
> > "if you want to pin the version" != "all users must explicitly specify
> the
> > version"
> >
> > I believe Jim is advocating for the latter. I'm advocating for the
> former.
>
> The problem that I'm now seeing is you're advocating not just that
> people should be able to pin a version. You're advocating for:
>
> 1. People don't need to pin the version. Fine.
>    1.1. Side note: perhaps you're actually advocating for "people should
>         not need to pin the version"? It's starting to sound that way.
> 2. The client should always default to the most recent compatible
>   version. Fine.
> 3. We should never break a user. Fine.
> 4. 1-3 must all be true always. Not fine.
>
> We can't reasonably make progress while having the latest API version be
> compatible with the previous API version. The combination above breaks
> down when we also want to continue to produce software (preferably
> quickly). We need to let one of those things go; they can't all be true
> at the same time.
>
> I think the best thing to let go is 1 or 2, personally. Where we are
> today is letting 3 go, and that's why we're stuck here.
>
>
Mmmm, close. I think I expanded on that in my last email (replying to
Dmitry) ... but... tldr;

1. yes
2. no -- the client should default to the minimum supported version. We got
that wrong previously, and that's what is hurting us now.
3. not quite -- we should be very intentional when ever we're going to
break a user AND we should only do it when there is no other option AND we
must provide a lot of warning and deprecation period.

-Deva



> // jim
>
> >
> >
> > -Deva
>
> >
> __________________________________________________________________________
> > OpenStack Development Mailing List (not for usage questions)
> > Unsubscribe:
> OpenStack-dev-request at lists.openstack.org?subject:unsubscribe
> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>
>
> __________________________________________________________________________
> OpenStack Development Mailing List (not for usage questions)
> Unsubscribe: OpenStack-dev-request at lists.openstack.org?subject:unsubscribe
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20150728/8ff5d91a/attachment-0001.html>