Re: [Xen-devel] [PATCH] xl: Change output from xl -N create to be more useful

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

On Fri, 2015-06-26 at 16:30 +0100, Ian Jackson wrote:
> Wei Liu writes ("Re: [PATCH] xl: Change output from xl -N create to be more 
> useful"):
> > On Fri, Jun 26, 2015 at 03:29:15PM +0100, Ian Jackson wrote:
> ...
> > > Note that this change is NOT BACKWARDS COMPATIBLE.  But it would only
> > > adversely affects anyone who uses `xl -N create' and then saves and
> > > processes the JSON.  (The output from xl list et al is not changed; it
> > > normally needs the domid.)  Such a user should probably have already
> > > have complained about the infelicitous output.  If they haven't it
> > > would be simple enough for them to bookend the output so as to provide
> > > compatible output.
> > > 
> > > If this backward compatibility problem is considered a blocker for
> > > this patch, then I will respin, with one of the following two
> > > workarounds:
> > >   - A new option to force sane output
> > >   - Generate output which contains the domain config twice,
> > >     once directly in the main struct, and a copy in "config"
> > 
> > I don't think keeping a broken interface for the sake of backward
> > compatibility is worth it.
> 
> The interface isn't unuseable.  You just have to use jq(1) or
> something to transform the output.
> 
> AFAIAA we have no in-tree consumers of libxl json domain configs and
> further I'm not aware of any out-of-tree consumers apart from the one
> I just introduced into the xs-ring3 ao abort test suite.
> 
> But, thanks for the favourable opinion :-).

I think we should just risk the change and if anyone notices and cares
we could consider retrofitting OUTPUT_FORMAT_JSON_XEN45 to xl. I think
it's unlikely anyone will notice.

Ian.



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