Re: [Qemu-devel] [PATCH v2 35/40] job: Add JOB_STATUS_CHANGE QMP event

[Eric Blake]

On 05/24/2018 12:36 PM, John Snow wrote:

> > > On 05/18/2018 09:21 AM, Kevin Wolf wrote:
> > > > This adds a QMP event that is emitted whenever a job transitions from
> > > > one status to another.
> > > >
> > > > Signed-off-by: Kevin Wolf <address@hidden>

> > The question that I was asking myself was just whether I'd literally
> > duplicate the existing events, just with s/BLOCK_JOB_/JOB_/, or whether
> > a single event with a status field can do. I think the latter is more
> > elegant (also because it can be implemented in a single place), even if
> > it is emitted a bit more often than strictly necessary.
>
> Code-wise I agree that this is more elegant; just wondering if the
> implications of the additional API guarantees were considered. This
> means we have to be a bit more careful about how we restructure the
> state machine in the future, I think.
>
> It also makes the "NULL" state visible, which I didn't really intend...
> It's probably fine, just a little quirky.

Is it worth a special case to avoid emitting the event on transition to 
the NULL state?

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