Re: [Qemu-devel] [PATCH 38/42] job: Add JOB_STATUS_CHANGE QMP event

[Eric Blake]

On 05/16/2018 03:46 PM, Kevin Wolf wrote:

> > > +{ 'event': 'JOB_STATUS_CHANGE',
> > > +  'data': { 'id': 'str',
> > > +            'status': 'JobStatus' } }
> >
> > Is it worth also trying to list the old state that the transition came from?
> > But that's new compared to what block jobs are currently doing, so if we
> > can't come up with a strong reason to add that, I'm okay.
>
> If a management tool needs this information (I don't see why), it just
> needs to keep track of the last state it had seen, no?

And if you miss an event, the previous state is not preserved for any 
later query-job command.  Exposing something in a (possibly-missed) 
event that is not available elsewhere doesn't buy us much.  So I agree - 
there is no strong reason to advertise the previous state.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org