[openstack-dev] [Ironic] Command structure for OSC plugin

Doug Hellmann doug at doughellmann.com
Wed Sep 2 14:20:56 UTC 2015


Excerpts from Tim Bell's message of 2015-09-02 05:15:35 +0000:
> That would be great to have plugins on the commands which are relevant to multiple projects… avoiding exposing all of the underlying projects as prefixes and getting more consistency would be very appreciated by the users.

That works in some cases, but in a lot of cases things that are
superficially similar have important differences in the inputs they
take. In those cases, it's better to be explicit about the differences
than to force the concepts together in a way that makes OSC present only
the least-common denominator interface.

Doug

> 
> Tim
> 
> From: Dean Troyer [mailto:dtroyer at gmail.com]
> Sent: 01 September 2015 22:47
> To: OpenStack Development Mailing List (not for usage questions) <openstack-dev at lists.openstack.org>
> Subject: Re: [openstack-dev] [Ironic] Command structure for OSC plugin
> 
> [late catch-up]
> 
> On Mon, Aug 24, 2015 at 2:56 PM, Doug Hellmann <doug at doughellmann.com<mailto:doug at doughellmann.com>> wrote:
> Excerpts from Brad P. Crochet's message of 2015-08-24 15:35:59 -0400:
> > On 24/08/15 18:19 +0000, Tim Bell wrote:
> > >
> > >From a user perspective, where bare metal and VMs are just different flavors (with varying capabilities), can we not use the same commands (server create/rebuild/...) ? Containers will create the same conceptual problems.
> > >
> > >OSC can provide a converged interface but if we just replace '$ ironic XXXX' by '$ openstack baremetal XXXX', this seems to be a missed opportunity to hide the complexity from the end user.
> > >
> > >Can we re-use the existing server structures ?
> 
> I've wondered about how users would see doing this, we've done it already with the quota and limits commands (blurring the distinction between project APIs).  At some level I am sure users really do not care about some of our project distinctions.
> 
> > To my knowledge, overriding or enhancing existing commands like that
> > is not possible.
> 
> You would have to do it in tree, by making the existing commands
> smart enough to talk to both nova and ironic, first to find the
> server (which service knows about something with UUID XYZ?) and
> then to take the appropriate action on that server using the right
> client. So it could be done, but it might lose some of the nuance
> between the server types by munging them into the same command. I
> don't know what sorts of operations are different, but it would be
> worth doing the analysis to see.
> 
> I do have an experimental plugin that hooks the server create command to add some options and change its behaviour so it is possible, but right now I wouldn't call it supported at all.  That might be something that we could consider doing though for things like this.
> 
> The current model for commands calling multiple project APIs is to put them in openstackclient.common, so yes, in-tree.
> 
> Overall, though, to stay consistent with OSC you would map operations into the current verbs as much as possible.  It is best to think in terms of how the CLI user is thinking and what she wants to do, and not how the REST or Python API is written.  In this case, 'baremetal' is a type of server, a set of attributes of a server, etc.  As mentioned earlier, containers will also have a similar paradigm to consider.
> 
> dt
> 



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