Re: [Qemu-devel] [PATCH 10/10] display: add -display app launching external application

From: Gerd Hoffmann <kraxel@redhat.com>
To: "Marc-André Lureau" <marcandre.lureau@gmail.com>
Cc: "Daniel P. Berrangé" <berrange@redhat.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	QEMU <qemu-devel@nongnu.org>,
	"Markus Armbruster" <armbru@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 10/10] display: add -display app launching external application
Date: Tue, 7 Aug 2018 16:30:55 +0200	[thread overview]
Message-ID: <20180807143055.pkx7l2ufb36lyq3b@sirius.home.kraxel.org> (raw)
In-Reply-To: <CAJ+F1C+=aucconH7EZ8D2g_Wir2wEeq4GMobK+jNPZ8b0LbZKA@mail.gmail.com>

  Hi,

> > spice arguments over time.  So if we want auto-launching of a remote app,
> > I think it is preferrable to do it via extra args to the existing
> > "-display spice" format. eg we could add a "client=yes|no" to control
> > launching the client
> >
> >    -display spice,client=yes
> 
> There is no -display spice, atm.
> 
> However there is a -display vnc.

That should not be there.  Now that we have a deprecation process
I should probably actually deprecate it in favor of -vnc.

> It's a bit unclear to me the relation between -display and
> -vnc/-spice/-curses etc. In the end, I tend to think of -display foo
> as a shortcut for a longer -foo configuration.

-display is for builtin UIs.  You can have exactly one of these.

-spice and -vnc is for remote protocols.  They can be used together with
builtin UIs (even though that isn't a typical use case).  Configuring
both spice and vnc works too.

-sdl and -curses are shortcuts for -display sdl and -display curses.

> So -display spice,client=yes is a reasonable proposal to me, making it
> clear that it will run spice. (client=yes is less clear to me but
> fine)

Hmm, this will both configure some standard stuff and start an external
application.  Doesn't really fit with "-spice ...".

Adding "-display remote-client" doesn't really fit either.  But still
looks better to me.  Or we just create a new -remote-client top level
switch.  Adding higher-level config options (protocol=spice/vnc,
monitor=on/off, serial=on/off, ...) is less confusing then (especially
vnc support :) ), compared to have a bunch of more -spice options which
only have an effect with client=yes.

Also:  remote-viewer accepts config files.  I'd suggest to write one, so
it is easy to restart remote-viewer.  Also I would not use a temp dir
for the files and sockets, but some fixed location.
/run/user/$uid/qemu/$vmname for example (where $vmname is whatever you
passed to qemu using -name).

cheers,
  Gerd