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From: Markus Armbruster <armbru@redhat.com>
To: John Snow <jsnow@redhat.com>
Cc: kwolf@redhat.com, ehabkost@redhat.com, qemu-devel@nongnu.org,
	wainersm@redhat.com, "Niteesh G. S." <niteesh.gs@gmail.com>,
	Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: GSoC Intro - TUI interface for QMP
Date: Wed, 09 Jun 2021 13:56:39 +0200	[thread overview]
Message-ID: <87sg1rp7yg.fsf@dusky.pond.sub.org> (raw)
In-Reply-To: <1577ce78-bf98-3f3d-7594-2b91d84967ec@redhat.com> (John Snow's message of "Tue, 8 Jun 2021 11:49:41 -0400")

John Snow <jsnow@redhat.com> writes:

> 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.
>
> We could prototype under the experimental QMP command x-help, and
> limit it to sending help for just one command at a time to limit data
> transfer.
>
> The client could cache the information. (Against what kind of an
> identifier? Can QEMU report some kind of token that uniquely
> identifies its binary or uniquely identifies the set of QAPI commands
> it supports?)

I proposed something like it to permit QMP clients cache
query-qmp-schema output.  Libvirt didn't want it, so it never got beyond
the idea stage.

> This has the potential to exceed our capacity this summer, but a
> prototype experiment might be helpful to inform future work anyway.

Beware of the risk that comes with shiny stretch goals: loss of focus.
I believe this is actually this GSoC project's main risk.



  reply	other threads:[~2021-06-09 11:58 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAN6ztm-J2GoQKkLb=Az0H2Q8UKK4oE3PgXg7g14=T53sQAUyDg@mail.gmail.com>
2021-05-21 19:02 ` Fwd: GSoC Intro - TUI interface for QMP Niteesh G. S.
2021-05-24 13:32   ` Stefan Hajnoczi
2021-05-24 17:34     ` John Snow
2021-06-02 11:08       ` Bruno Piazera Larsen
2021-06-11 14:06       ` Vladimir Sementsov-Ogievskiy via
2021-05-26 15:35     ` Fwd: " Niteesh G. S.
2021-06-01 23:47       ` John Snow
2021-06-08 15:01         ` Markus Armbruster
2021-06-08 15:49           ` John Snow
2021-06-09 11:56             ` Markus Armbruster [this message]
2021-06-09 17:06               ` John Snow
2021-06-10  7:19                 ` Markus Armbruster
2021-06-09 12:07             ` Daniel P. Berrangé
2021-06-10 14:35               ` John Snow
2021-06-09 12:03           ` Daniel P. Berrangé

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