From: Kevin Wolf <kwolf@redhat.com>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
"Daniel P. Berrangé" <berrange@redhat.com>,
"Denis V. Lunev" <den@virtuozzo.com>,
"Cleber Rosa" <cleber@redhat.com>,
"Stefan Hajnoczi" <stefanha@gmail.com>,
"Markus Armbruster" <armbru@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Dominik Csapak" <d.csapak@proxmox.com>,
"John Snow" <jsnow@redhat.com>,
"Eduardo Habkost" <ehabkost@redhat.com>
Subject: Re: qmp-shell for GSoC/Outreachy?
Date: Fri, 7 Feb 2020 11:49:17 +0100 [thread overview]
Message-ID: <20200207104917.GD6031@linux.fritz.box> (raw)
In-Reply-To: <20200206182639.GL3655@work-vm>
Am 06.02.2020 um 19:26 hat Dr. David Alan Gilbert geschrieben:
> * Kevin Wolf (kwolf@redhat.com) wrote:
> > Am 06.02.2020 um 10:40 hat Markus Armbruster geschrieben:
> > > >> On 2/5/20 8:09 AM, Kevin Wolf wrote:
> > > >> > Am 28.01.2020 um 11:59 hat Kevin Wolf geschrieben:
> > > >> >>>> The other part that it needs to solve is how to be available by default
> > > >> >>>> without specifying anything on the command line. Basically, if I press
> > > >> >>>> Ctrl-Alt-2, I want to get to a monitor shell. If that shell is
> > > >> >>>> implemented internally or by an external Python process, I don't mind.
> > > >> >>>
> > > >> >>> That is a harder part. (I rarely use Ctrl-Alt-2 actually; I mostly
> > > >> >>> use HMP on stdin).
> > > >> >>
> > > >> >> I don't think it would be that hard, actually.
> > > >> >>
> > > >> >> If you have a -qmp-shell option that takes a chardev and defaults to vc,
> > > >> >> you've solved the part with both stdio and Ctrl-Alt-2. Now all you need
> > > >> >> to do is launch the Python child process, pass it a pair of pipes for
> > > >> >> communication and forward everything between the pipes and the chardev.
> > > >> >>
> > > >> >> (That's the theory anyway.)
> > > >> >
> > > >> > If someone is interested, I did a quick proof-of-concept hack:
> > > >> >
> > > >> > https://repo.or.cz/qemu/kevin.git/shortlog/refs/heads/qmp-shell
> > > >> >
> > > >> > It doesn't clean up anything properly (including the qmp-shell processes
> > > >> > it starts), but it spawns a usable qmp-shell on a user-specified
> > > >> > character device. stdio seems to work, though without readline
> > > >> > functionality (I suppose I still have line-buffering somewhere), vc
> > > >> > doesn't really work at all yet.
> > > >> >
> > > >> > Try it out like this:
> > > >> >
> > > >> > $ ./qemu-storage-daemon --chardev stdio,id=m --monitor m,mode=qmp-shell
> > > >> > monitor_qmp_event: 1
> > > >> > Welcome to the QMP low-level shell!
> > > >> > Connected to QEMU 4.2.50
> > > >> >
> > > >> > (QEMU) query-version
> > > >> > {"return": {"qemu": {"micro": 50, "major": 4, "minor": 2}, "package": "v4.2.0-1188-gd95a3885a9"}}
> > > >> > (QEMU) quit
> > > >> >
> > > >> > (Or use x86_64-softmmu/qemu-system-x86_64, but it's based on the
> > > >> > refactorings in the storage daemon branch, so why not try both at once?)
> > > >> >
> > > >> > Polishing this to make it mergable would still require substantial work,
> > > >> > so at the moment I'm not planning to do this. But if someone wants to
> > > >> > pick it up, feel free (just let us know).
> > > >> >
> > > >> > Hm, in fact... A qmp-shell GSoC project?
> > > >> >
> > > >>
> > > >> That would be great. I worry that we should have a clear vision for the
> > > >> syntax before we give this project to an intern, though. With a clear
> > > >> vision and an outline for deliverables, it's an incredibly appropriate
> > > >> project.
> > > >>
> > > >> Some things I think we want to define before we start:
> > > >>
> > > >> 1. What are we trying to achieve with a standalone shell?
> > >
> > > Projects without a clear goal rarely succeed. Success within three
> > > months is even rarer.
> > >
> > > >> 2. What syntax should it use?
> > >
> > > Leaving that to a GSoC student amounts to setting up for failure.
> >
> > I think this subthread shows that we actually have many separate
> > projects that people wish to have someone work on. Each of them is
> > probably a bit too small for a whole GSoC, but all of them together are
> > probably too much. So I'll guess the student would pick maybe two of
> > them, and if time is left at the end, more can be added as a bonus.
> >
> > 1. Something like --monitor mode=qmp-shell that just spawns an external
> > Python script and passes it a QMP socket. This is the fundamental
> > building block for having any kind of external monitor script
> > actually integrated in QEMU, so I think just running the existing
> > qmp-shell this way (with proper support for at least stdio and vc
> > chardevs) would make sense as a first milestone.
>
> I was originally going to suggest that should be sugar for a
> -chardev filter that takes an in/out chardev - but I don't know how
> you'd handle tty stuff like formatting and tab completion etc.
Originally I thought the same, but it's actually not enough. The
external process needs not only stdio connected to the chardev, but also
another file descriptor for a QMP socket.
I guess tab completion should be possible if we can turn off line
buffering. Not sure what's the problem with formatting.
> > 2. Rewriting qmp-shell to use a better syntax for nested data
> > structures. This would have to be defined before the project starts.
> >
> > 3. Improving qmp-shell UI-wise, e.g. by having better autocompletion,
> > support for counting brackets, or whatever else was mentioned. We
> > have a few ideas, and there's room for the student to add their own
> > ideas, too.
> >
> > 4. Something HMP-like. This isn't QMP any more, so it could as well be a
> > separate script (hmp-shell?). But it could also be integrated in
> > qmp-shell in the form of additional commands that are implemented
> > client-side. Or maybe have a single shell, but have a QMP mode and an
> > HMP mode and the user can switch between these modes.
> >
> > The syntax for the HMP shell/mode could be the same or different from
> > the QMP syntax. This would have to be defined beforehand, too.
>
> separate script sharing the qmp interface code?
I would certainly expect that any QMP/HMP shell code uses the existing
QEMUMonitorProtocol Python class. qmp-shell already does.
Maybe they could share a bit more (command parsing?) if we want to have
separate scripts for HMP and QMP. Though actually I think I like the
idea of a combined QMP/HMP shell better at the moment.
Kevin
next prev parent reply other threads:[~2020-02-07 10:50 UTC|newest]
Thread overview: 183+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-20 16:13 Making QEMU easier for management tools and applications Stefan Hajnoczi
2019-12-20 21:07 ` Richard W.M. Jones
2020-01-02 11:26 ` Stefan Hajnoczi
2019-12-21 9:02 ` Markus Armbruster
2019-12-23 15:04 ` Michal Prívozník
2020-01-07 9:36 ` Kevin Wolf
2020-01-07 10:55 ` Michal Privoznik
2020-01-07 12:57 ` Kevin Wolf
2020-01-07 17:53 ` Christophe de Dinechin
2019-12-24 13:41 ` Daniel P. Berrangé
2020-01-22 22:28 ` John Snow
2020-01-23 7:19 ` Markus Armbruster
2020-01-23 17:58 ` John Snow
2020-01-23 19:01 ` Daniel P. Berrangé
2020-01-23 21:07 ` John Snow
2020-01-24 7:59 ` Markus Armbruster
2020-01-24 10:27 ` Daniel P. Berrangé
2020-01-24 14:38 ` Kevin Wolf
2020-01-24 18:23 ` John Snow
2020-01-24 18:30 ` Dr. David Alan Gilbert
2020-01-24 18:48 ` John Snow
2020-01-24 18:52 ` Dr. David Alan Gilbert
2020-01-24 18:58 ` John Snow
2020-01-25 10:18 ` Markus Armbruster
2020-01-27 10:18 ` Daniel P. Berrangé
2020-01-27 12:48 ` Markus Armbruster
2020-01-27 11:56 ` Kevin Wolf
2020-01-27 12:04 ` Peter Maydell
2020-01-27 20:11 ` John Snow
2020-01-27 22:38 ` Paolo Bonzini
2020-01-28 0:37 ` John Snow
2020-01-28 10:16 ` Daniel P. Berrangé
2020-01-28 10:39 ` Kevin Wolf
2020-01-28 15:36 ` Markus Armbruster
2020-01-31 12:25 ` Eric Blake
2020-01-28 10:28 ` Kevin Wolf
2020-01-28 12:36 ` Markus Armbruster
2020-01-28 12:54 ` Kevin Wolf
2020-01-28 13:45 ` Gerd Hoffmann
2020-01-31 6:50 ` Markus Armbruster
2020-01-31 7:48 ` Paolo Bonzini
2020-01-31 8:09 ` Markus Armbruster
2020-02-03 20:07 ` Andrea Bolognani
2020-02-04 9:58 ` Markus Armbruster
2020-01-31 12:27 ` Eric Blake
2020-02-02 9:21 ` Kevin Wolf
2020-02-02 10:44 ` Paolo Bonzini
2020-02-03 6:20 ` Markus Armbruster
2020-02-03 8:48 ` Markus Armbruster
2020-01-27 20:12 ` Dr. David Alan Gilbert
2020-01-24 20:34 ` John Snow
2020-01-27 8:35 ` Gerd Hoffmann
2020-01-27 12:13 ` Kevin Wolf
2020-01-27 16:18 ` Gerd Hoffmann
2020-01-24 9:50 ` Daniel P. Berrangé
2020-01-25 11:52 ` Paolo Bonzini
2020-01-27 10:05 ` Daniel P. Berrangé
2020-01-27 8:25 ` Tooling to help humans use JSON (was: Making QEMU easier for management tools and applications) Markus Armbruster
2020-01-27 9:06 ` Making QEMU easier for management tools and applications Markus Armbruster
2020-01-27 10:00 ` Daniel P. Berrangé
2020-01-27 14:35 ` Kevin Wolf
2020-01-27 20:29 ` Dr. David Alan Gilbert
2020-01-28 10:59 ` Kevin Wolf
2020-02-05 13:09 ` Kevin Wolf
2020-02-05 19:09 ` qmp-shell for GSoC/Outreachy? (Was: Re: Making QEMU easier for management tools and applications) John Snow
2020-02-05 19:49 ` Dr. David Alan Gilbert
2020-02-06 9:40 ` qmp-shell for GSoC/Outreachy? Markus Armbruster
2020-02-06 10:09 ` Daniel P. Berrangé
2020-02-06 12:11 ` Markus Armbruster
2020-02-06 12:15 ` Daniel P. Berrangé
2020-02-06 18:02 ` Dr. David Alan Gilbert
2020-02-07 21:03 ` John Snow
2020-02-08 7:17 ` Markus Armbruster
2020-02-06 14:21 ` Kevin Wolf
2020-02-06 18:26 ` Dr. David Alan Gilbert
2020-02-07 10:49 ` Kevin Wolf [this message]
2020-02-07 21:23 ` John Snow
2020-02-08 7:25 ` Markus Armbruster
2020-02-10 11:59 ` Kevin Wolf
2020-02-10 12:26 ` Kevin Wolf
2020-02-06 18:18 ` Dr. David Alan Gilbert
2020-02-07 7:47 ` Markus Armbruster
2020-02-07 21:31 ` Eric Blake
2020-02-08 7:34 ` Markus Armbruster
2020-02-07 21:56 ` John Snow
2020-02-07 20:56 ` John Snow
2020-01-27 20:59 ` Making QEMU easier for management tools and applications John Snow
2020-01-28 10:16 ` Markus Armbruster
2020-01-28 19:21 ` John Snow
2020-01-24 6:38 ` Markus Armbruster
2020-01-25 22:34 ` Christophe de Dinechin
2020-01-25 11:55 ` Paolo Bonzini
2020-01-02 14:47 ` Stefan Hajnoczi
2020-01-16 11:03 ` Kashyap Chamarthy
2020-01-20 9:55 ` Stefan Hajnoczi
2020-01-20 13:57 ` Kashyap Chamarthy
2020-01-25 11:41 ` Paolo Bonzini
2020-01-27 19:41 ` John Snow
2020-01-02 15:05 ` Dr. David Alan Gilbert
2020-01-13 13:44 ` Markus Armbruster
2019-12-24 13:00 ` Daniel P. Berrangé
2020-01-02 14:22 ` Stefan Hajnoczi
2020-01-22 22:42 ` John Snow
2020-01-23 7:21 ` Markus Armbruster
2020-01-23 10:27 ` Daniel P. Berrangé
2020-01-23 18:13 ` John Snow
2020-01-23 19:12 ` Daniel P. Berrangé
2020-01-02 15:10 ` Dr. David Alan Gilbert
2020-01-07 17:11 ` Christophe de Dinechin
2020-01-08 10:43 ` Kevin Wolf
2020-01-08 11:40 ` Christophe de Dinechin
2020-01-08 13:38 ` Kevin Wolf
2020-01-14 13:04 ` Markus Armbruster
2020-01-14 17:31 ` Christophe de Dinechin
2020-01-15 9:20 ` Markus Armbruster
2020-01-15 9:34 ` Christophe de Dinechin
2020-01-15 12:15 ` Markus Armbruster
2020-01-15 12:19 ` Daniel P. Berrangé
2020-01-15 14:02 ` Markus Armbruster
2020-01-30 21:09 ` Improving QOM documentation [Was: Re: Making QEMU easier for management tools and applications] Kashyap Chamarthy
2020-01-31 6:11 ` Markus Armbruster
2020-01-31 7:46 ` Paolo Bonzini
2020-01-31 15:37 ` Christophe de Dinechin
2020-01-31 16:28 ` Paolo Bonzini
2020-01-31 9:50 ` Kashyap Chamarthy
2020-01-31 10:35 ` Peter Maydell
2020-01-31 11:02 ` Paolo Bonzini
2020-01-31 15:22 ` Kashyap Chamarthy
2020-01-31 17:23 ` Markus Armbruster
2020-02-03 8:56 ` Paolo Bonzini
2020-02-03 9:54 ` Markus Armbruster
2020-02-03 15:21 ` Paolo Bonzini
2020-02-04 8:42 ` Markus Armbruster
2020-01-31 16:39 ` Markus Armbruster
2020-01-20 10:08 ` Making QEMU easier for management tools and applications Stefan Hajnoczi
2020-01-21 5:42 ` Markus Armbruster
2020-01-21 11:32 ` Stefan Hajnoczi
2020-01-21 12:03 ` Marc-André Lureau
2020-01-21 13:36 ` Integrating QOM into QAPI (was: Making QEMU easier for management tools and applications) Markus Armbruster
2020-01-21 14:36 ` Daniel P. Berrangé
2020-01-21 15:01 ` Integrating QOM into QAPI Markus Armbruster
2020-01-21 15:11 ` Marc-André Lureau
2020-01-21 16:21 ` Peter Maydell
2020-01-22 5:16 ` Getting whole-tree patches reviewed and merged (was: Integrating QOM into QAPI) Markus Armbruster
2020-02-07 21:53 ` Getting whole-tree patches reviewed and merged Eric Blake
2020-02-10 11:26 ` Paolo Bonzini
2020-02-10 16:04 ` Markus Armbruster
2020-02-10 16:12 ` Peter Maydell
2020-01-22 10:50 ` Integrating QOM into QAPI Alex Bennée
2020-01-22 12:24 ` Markus Armbruster
2020-01-22 12:42 ` Marc-André Lureau
2020-01-22 13:28 ` Peter Maydell
2020-01-22 13:32 ` Marc-André Lureau
2020-01-23 7:37 ` Markus Armbruster
2020-01-24 18:32 ` Paolo Bonzini
2020-01-25 4:44 ` Marc-André Lureau
2020-01-25 9:28 ` Paolo Bonzini
2020-01-25 21:25 ` Peter Maydell
2020-01-26 8:09 ` Christophe de Dinechin
2020-01-26 9:11 ` Marc-André Lureau
2020-01-26 16:47 ` Paolo Bonzini
2020-01-27 19:05 ` Christophe de Dinechin
2020-01-27 19:05 ` Christophe de Dinechin
2020-01-26 15:04 ` Peter Maydell
2020-01-27 19:05 ` Christophe de Dinechin
2020-01-28 8:00 ` Markus Armbruster
2020-01-28 10:03 ` Daniel P. Berrangé
2020-01-29 12:42 ` Christophe de Dinechin
2020-01-15 9:35 ` Making QEMU easier for management tools and applications Marc-André Lureau
2020-01-15 12:25 ` Markus Armbruster
2020-01-25 17:18 ` Paolo Bonzini
2020-01-27 9:30 ` Markus Armbruster
2020-01-13 16:30 ` Stefan Hajnoczi
2020-02-04 15:54 ` Summary of " Markus Armbruster
2020-02-05 6:38 ` Markus Armbruster
2020-02-10 10:56 ` Stefan Hajnoczi
2020-02-10 11:01 ` Peter Maydell
2020-02-10 11:08 ` Daniel P. Berrangé
2020-02-10 11:29 ` Peter Maydell
2020-02-10 11:04 ` Paolo Bonzini
2020-02-10 16:43 ` Markus Armbruster
2020-02-12 13:54 ` Stefan Hajnoczi
2020-02-12 14:03 ` Daniel P. Berrangé
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