Re: [Qemu-devel] [Qemu-block] Making QMP 'block-job-cancel' transactionable

[Kashyap Chamarthy <kchamart@redhat.com>]

On Tue, Apr 11, 2017 at 11:42:28AM +0200, Markus Armbruster wrote:
> Eric Blake <eblake@redhat.com> writes:
> 
> > On 04/04/2017 08:28 AM, Kashyap Chamarthy wrote:
> >
> >>> Minor or not, it is a useful viewpoint. Either way, as long as the new
> >>> way of getting a transactional non-pivot successful completion is
> >>> something that libvirt can learn via introspection, 
> >> 
> >> Can you elaborate a little more on the above, for my own edification --
> >> how might it be possible for "libvirt can learn via introspection"?  Is
> >> it via some method using the QMP 'query-commands' /
> >> 'query-command-line-options'?
> >
> > Those, and query-qmp-schema.
> 
> Avoid query-command-line-options if you can.  If you can't, know its
> limitations and quirks.

Thanks; I actually meant to mention 'query-qmp-schema' (thanks to Eric
for correcting).  And I didn't fortet your reminder of the
incompleteness / limitations of 'query-command-line-options' from your
KVMForum 2015 presentation :-)

> 
> >                               If the change includes the addition of
> > something new in the .json files describing QMP, then query-qmp-schema
> > will let libvirt probe whether the version of qemu it it talking to has
> > that new field or not (presumably, in this case it would be a new
> > optional bool member to select the mode when creating a job, as well as
> > a new command visible through query-commands to change the mode of a
> > running job).

-- 
/kashyap