libvirt users - Feb 2017 - Determining domain job kind from job stats?

Hi, is there a reliable way to find out to what kind of job does the
information returned from virDomainGetJobStats or provided in
VIR_DOMAIN_EVENT_ID_JOB_COMPLETED event callback belong to?

I'm specifically interested in distinguishing host-to-host migration
jobs (e.g. those started by virDomainMigrateToUri* functions) from other
jobs.  If there is no better way, I'm thinking about examining presence
or values of certain fields in the stats.  I'd be fine with that as long
as I can be sure it's a reliable way to identify the job kind.

Thanks,
Milan

On Fri, Feb 10, 2017 at 21:50:19 +0100, Milan Zamazal
wrote:
> Hi, is there a reliable way to find out to what kind of job does the
> information returned from virDomainGetJobStats or provided in
> VIR_DOMAIN_EVENT_ID_JOB_COMPLETED event callback belong to?
No, libvirt expects that the caller knows what job it started. All jobs
currently reported using virDomainGetJobStats API or
VIR_DOMAIN_EVENT_ID_JOB_COMPLETED event are internally implemented as
migration in QEMU driver (either to a file or to a network socket),
which may confuse any heuristics for detecting the job type from the set
of fields returned by libvirt.

What is the problem you are trying to solve?

Jirka

Jiri Denemark <jdenemar@redhat.com> writes:
> On Fri, Feb 10, 2017 at 21:50:19 +0100, Milan Zamazal wrote:
>> Hi, is there a reliable way to find out to what kind of job does the
>> information returned from virDomainGetJobStats or provided in
>> VIR_DOMAIN_EVENT_ID_JOB_COMPLETED event callback belong to?
>
> No, libvirt expects that the caller knows what job it started. All jobs
> currently reported using virDomainGetJobStats API or
> VIR_DOMAIN_EVENT_ID_JOB_COMPLETED event are internally implemented as
> migration in QEMU driver (either to a file or to a network socket),
> which may confuse any heuristics for detecting the job type from the set
> of fields returned by libvirt.
I see, thank you for explanation.
> What is the problem you are trying to solve?
There are basically two problems:

- When the job completion callback is called, I need to distinguish what
  kind of job was it to perform the appropriate actions.  It would be
  easier if I knew the job type directly in the callback (no need to
  coordinate anything), but "external" job tracking is also possible.

- If I lost track of my jobs (e.g. because of a crash and restart), I'd
  like to find out whether a given VM is migrating.  Examining the job
  looked like a good candidate to get the information, but apparently
  it's not.  Again, I can probably arrange things to handle that, but to
  get the information directly from libvirt (not necessarily via job
  info) would be easier and more reliable.

Thanks,
Milan