[libvirt] Determining domain job kind from job stats?

[Daniel P. Berrange]

On Tue, Apr 11, 2017 at 09:49:42AM +0200, Jiri Denemark wrote:
> On Mon, Apr 10, 2017 at 12:01:43 +0100, Daniel P. Berrange wrote:
> > On Mon, Apr 10, 2017 at 12:58:09PM +0200, Milan Zamazal wrote:
> > > I looked how the change could be implemented.  Could you please help me
> > > clarify some things?
> > > 
> > > - I think a new member should be added to _virDomainJobInfo for the
> > >   purpose.  What would be a good name for it?  Maybe "operation"?
> > > - Do I need to care about backends other than QEMU?
> > > - Jobs are classified by qemuDomainAsyncJob, which is a QEMU specific
> > >   type.  Is it OK to use such structures in virsh-domain.c or is there
> > >   any additional abstraction needed?
> > 
> > I don't much like the idea of exposing the QEMU job operation names
> > in the public API. 
> > 
> > Perhaps we instead need to have the method which starts the job, return
> > an integer "job id" that is then reported against the job, so apps can
> > match them up.
> 
> The problem with "job id" is that only the process which started the job
> would know what it means. Not to mention it would require a lot of API
> changes.
> 
> I think we should just introduce a new virDomainJobSomething enum as
> 
>     VIR_DOMAIN_JOB_SOMETHING_INCOMING_MIGRATION,
>     VIR_DOMAIN_JOB_SOMETHING_OUTGOING_MIGRATION,
>     VIR_DOMAIN_JOB_SOMETHING_SAVE,
>     VIR_DOMAIN_JOB_SOMETHING_RESTORE,
>     ...
> 
> and report it in virDomainGetJobStat (definitely not in
> _virDomainJobInfo as it would break ABI).
> 
> I'm not sure what the best name for "Something" would be. "Operation",
> "Action", or something else?

IMHO It would be an "Operation", since a single logical operation can involve
running multiple actions.

Regards,
Daniel
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