Re: [Qemu-block] [Qemu-devel] [PATCH 7/7] qemu-img: allow specifying image as a set of options args

[Daniel P. Berrange]

On Wed, Dec 23, 2015 at 07:03:34PM +0100, Paolo Bonzini wrote:
> 
> 
> On 23/12/2015 17:55, Daniel P. Berrange wrote:
> >>> > > A third option would be to keep using positional arguments, but
> >>> > > add a '--source-opts' *boolean* flag to indicate how to interpret
> >>> > > the positional arguments.  ie without --source-opts we use the
> >>> > > historic syntax, but with --source-opts, we assume the full QemuOpts
> >>> > > syntax.
> >> > 
> >> > Oh, nice compromise. It's relatively discoverable (grep --help output),
> >> > preserves back-compat of old scripts, and offers the full power for
> >> > clients that want the full power.
> > I've implemented this now and it makes the patches soooo much simpler
> > too, so an added win.
> 
> Hmm, looks like I'm a bit late, but here's another possibility: making
> --source-options (aka -o) take an argument, and if you specify both
> --source-options and the positional argument, the latter is added as a
> "file" key.
> 
> This way you can do "qemu-img info --object secret... -o secret=foo
> iscsi://foo/".

This gets somewhat messy for the commands which needs to accept more
than one filename, eg 'compare' (2 files) and 'convert' (any number
of files)'.  eg if you have 3 positional file names and want to set
an option on the 2nd file, '-o foo=bar' is not really going to say
which positional file it applies to. The style I just implemented
with the boolean '--image-opts' flag avoids this messiness nicely.

Regards,
Daniel
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