Re: [RFC PATCH 00/13] migration: Unify capabilities and parameters

[Peter Xu]

On Mon, Apr 14, 2025 at 02:40:25PM -0300, Fabiano Rosas wrote:
> > Can we make the two approaches mutually exclusive ? Taking your
> > 'migrate' command example addition:
> >
> >   { 'command': 'migrate',
> >     'data': {'*uri': 'str',
> >              '*channels': [ 'MigrationChannel' ],
> >   +          '*config': 'MigrationConfig',
> >              '*detach': 'bool', '*resume': 'bool' } }
> >
> > if 'migrate' is invoked with the '*config' data being non-nil,
> > then we should ignore *all* global state previously set with
> > migrate-set-XXXX, and exclusively use '*config'.
> >
> > That gives a clean semantic break between old and new approaches,
> > without us having to worry about removing the existing commands
> > quickly.
> >
> 
> Good idea. I will need to do something about the -global options because
> they also set the defaults for the various options. But we should be
> able to decouple setting defaults from -global. Or I could just apply
> -global again on top of what came in '*config'.

Would it still be possible that we allow whatever options attached to the
"migrate" command to only overwrite the globals (either set via -global or
migrate-set-* QMP commands), rather than ignoring them completely?

If so, we don't need to do anything with current -global and it'll keep
working.  It's the same to most existing way to set the migration options
(e.g., otherwise do we plan to disable HMP "migrate" usage?).

Making the above '*config' to only overwrite also do not stand against the
mgmt using it to ignore the default options, after all the mgmt can decide
to always set everything in the '*config' then it's the same as ignoring
the globals?

-- 
Peter Xu