Re: GSoC Intro - TUI interface for QMP

From: "Daniel P. Berrangé" <berrange@redhat.com>
To: John Snow <jsnow@redhat.com>
Cc: kwolf@redhat.com, ehabkost@redhat.com, qemu-devel@nongnu.org,
	wainersm@redhat.com, Markus Armbruster <armbru@redhat.com>,
	"Niteesh G. S." <niteesh.gs@gmail.com>,
	Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: GSoC Intro - TUI interface for QMP
Date: Wed, 9 Jun 2021 13:07:42 +0100	[thread overview]
Message-ID: <YMCvDpooagPkPN2H@redhat.com> (raw)
In-Reply-To: <1577ce78-bf98-3f3d-7594-2b91d84967ec@redhat.com>

On Tue, Jun 08, 2021 at 11:49:41AM -0400, John Snow wrote:
> On 6/8/21 11:01 AM, Markus Armbruster wrote:
> > John Snow <jsnow@redhat.com> writes:
> > 
> > [...]
> > 
> > > A challenge will be where to pull the help text from. The QEMU server
> > > is not capable (today) of sending help information over the QMP socket
> > > itself.
> > > 
> > > We will need to implement a QMP command inside of QEMU directly that
> > > is capable of delivering this information to the client so that it can
> > > render it.
> > > 
> > > Since not all versions of QEMU will have this feature, the qmp-shell
> > > will need to be able to gracefully deal with the lack of help text,
> > > displaying an error indicating that this version of QEMU does not have
> > > help information compiled into it.
> > 
> > The doc text is bulky: my bld/docs/manual/interop/qemu-qmp-ref.html is
> > 1.7 MiB and growing.  Less lavish markup results in smaller data.  We
> > may want to store it compressed, or load it on demand.  We might even
> > have to make it compile-time optional for some use cases.
> > 
> > 
> 
> ACK, understood.
> 
> raw QAPI directory, including only the json files, is "only" 551.3 kB.
> 
> I assume we can compile help text to something json (or json-like) and then
> compress it. Perhaps we could compile something like
> qapi-help-introspect.json.tgz and load it on-demand from the QEMU binary
> when help text is requested.

I think that's  overthinking things. Even a small QEMU install is 
10s of MB in size once you add up the qemu binary, firmware blobs
and depedancies. If we only keep the raw help text from the json,
we'll have < 1/2 MB, which is lost in the noise of the overall
deploymnt size. No need for compression or complex load-on-demand,
just keep it small and simple.

Regards,
Daniel
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