Re: [Qemu-devel] Proposal for extensions of block job commands in QEMU 1.2

[Anthony Liguori]

On 05/21/2012 09:09 AM, Kevin Wolf wrote:
> Am 21.05.2012 15:59, schrieb Luiz Capitulino:
> > On Fri, 18 May 2012 19:08:42 +0200
> > Paolo Bonzini<address@hidden>  wrote:
> >
> > > Modified QMP commands
> > > =====================
> >
> > As we have discussed on the ML, we're not going to extend QMP commands.
> >
> > I understand your reasoning, and since the beginning I thought this was
> > something useful to do, but we've already settled for not doing this.
> >
> > I also think that we shouldn't have exceptions, as in practice this means
> > we're extending commands anyway. So either, we do it or we don't.
>
> What's the reason for disallowing command extensions? I'd find it rather
> silly to maintain ten different functions that all do basically the
> same, just that some of them have more optional parameters than others...

How does a client figure out if the command supports the new options?  And start 
writing the Python code for it before answering...  Even if we exposed the 
schema via QMP, checking via schema interpretation would be a nightmare.

Regards,

Anthony Liguori

> Kevin