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From: Anthony Liguori <anthony@codemonkey.ws>
To: Avi Kivity <avi@redhat.com>
Cc: "ehabkost@redhat.com" <ehabkost@redhat.com>,
	Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
	"jan.kiszka@siemens.com" <jan.kiszka@siemens.com>,
	"dlaor@redhat.com" <dlaor@redhat.com>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	Luiz Capitulino <lcapitulino@redhat.com>,
	Filip Navara <filip.navara@gmail.com>,
	Vincent Hanquez <tab@snarc.org>
Subject: Re: [Qemu-devel] [PATCH 01/11] QMP: Introduce specification file
Date: Sun, 28 Jun 2009 19:42:55 -0500	[thread overview]
Message-ID: <4A480E0F.6030000@codemonkey.ws> (raw)
In-Reply-To: <4A47A9B4.4050600@redhat.com>

Avi Kivity wrote:
> First, I would like to consider the protocol mostly from the point of 
> view of clients, not qemu, and certainly not current qemu code.  There 
> is only one qemu, but many clients.  Code problems can be solved 
> tomorrow, but interface problems remain forever.

I'm trying to consider both.  We need something that we can get into a 
robust state in 6 months.  I don't want to undertake a massive effort 
that will require major changes because history shows that we'll end up 
with something that doesn't really do the job.

> Second, I think it fits quite nicely.  Positional arguments are nasty 
> when you have many of them, especially when some are optional.  And we 
> already support dictionaries: -drive file=blah,cache=none.  We make a 
> dictionary interface, and have both the command line parser and the 
> monitor json thing implement it.

It a fair bit of complexity but I don't think it's too problematic.  The 
current monitor abstraction doesn't have a mechanism to define names of 
arguments but I think it could be added relatively easily although it 
wouldn't be so elegant (another parameter with comma deliminated names 
would do the trick).

>
> Yes, I meant { 'type': 'respose', 'id': 'foo', 'return': value }.  
> 'type' is the new =, and 'id' is the tag.  If multiple return values 
> are needed, value can be a list or dictionary.

I really don't like the syntax you proposed but that's an aesthetic 
problem.  This is an interface consumed by non humans so I don't think 
it's worth arguing about something that is just as easily parsed by a 
computer even if it's hideously ugly :-)

So I'll defer to whatever Luiz (or whoever sends patches) decides to do 
as long as it meets the same requirements.

The main thing missing from the first patchset that this thread has 
revealed is a formal grammar for the data.  This is an important 
requirement to ensure that it's reasonably parse-able by both ends.

>>> I think it's fine to drop jsonrpc as the standard (but retain its 
>>> features) and just adopt json for encoding.
>>
>> Yeah, I think if we focus on defining a grammar and semantics, if it 
>> happens to look like JSON, I don't really care.  I just don't want to 
>> adopt the baggage of json and particularly json-rpc.
>
> If 'looks like' == 'compatible with', I agree.

You lost me here.  JSON interoperability cannot be a requirement.  
Otherwise, we're going to get stuck dealing with all the warts of JSON.  
I don't want people to assume they can just use a JSON parser.

You seem to have conflicting requirements.   You want JSON compatibility 
but then you want C-style floats which JSON doesn't support.

I don't mind if this ends up looking like JSON, but I don't want to have 
to enforce that it's remains JSON compatible in the long term.  We 
should have our own grammar that we can version and that people can use 
as the basis of a client.

If being pure JSON is important to someone (and I don't think it will 
be), then someone can write a JSON proxy.  You don't need any RPC 
knowledge to do that so it can be relatively future-proof.

Regards,

Anthony Liguori

  reply	other threads:[~2009-06-29  0:43 UTC|newest]

Thread overview: 199+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cover.1245730845.git.lcapitulino@redhat.com>
2009-06-23  4:28 ` [Qemu-devel] [PATCH 01/11] QMP: Introduce specification file Luiz Capitulino
2009-06-23  8:55   ` [Qemu-devel] " Avi Kivity
2009-06-23  9:57     ` Daniel P. Berrange
2009-06-23 10:08       ` Avi Kivity
2009-06-23 13:22       ` Luiz Capitulino
2009-06-23 13:31         ` Avi Kivity
2009-06-23 13:06     ` Luiz Capitulino
2009-06-23 13:10       ` Daniel P. Berrange
2009-06-23 17:12         ` Luiz Capitulino
2009-06-23 13:27       ` Avi Kivity
2009-06-23 17:15         ` Luiz Capitulino
2009-06-23 13:12     ` Anthony Liguori
2009-06-23 13:30       ` Avi Kivity
2009-06-23 13:34         ` Eduardo Habkost
2009-06-23 13:40         ` Anthony Liguori
2009-06-23 15:01           ` Avi Kivity
2009-06-23 15:47             ` Anthony Liguori
2009-06-23 16:02               ` Avi Kivity
2009-06-23 17:20       ` Luiz Capitulino
2009-06-23 14:45   ` [Qemu-devel] " Vincent Hanquez
2009-06-23 15:56     ` Avi Kivity
2009-06-23 15:56       ` Anthony Liguori
2009-06-23 16:04         ` Avi Kivity
2009-06-23 16:09           ` Anthony Liguori
2009-06-23 16:15             ` Avi Kivity
2009-06-23 18:32               ` Anthony Liguori
2009-06-23 18:47                 ` Avi Kivity
2009-06-23 19:00                   ` Anthony Liguori
2009-06-23 19:44                     ` Avi Kivity
2009-06-23 19:52                     ` Avi Kivity
2009-06-23 20:07                       ` Anthony Liguori
2009-06-23 20:13                         ` Avi Kivity
2009-06-23 22:02                           ` Anthony Liguori
2009-06-23 22:02                     ` Vincent Hanquez
2009-06-23 22:50                       ` Anthony Liguori
2009-06-24  1:01                         ` Vincent Hanquez
2009-06-24 11:55                           ` James
2009-06-24 12:09                             ` Daniel P. Berrange
2009-06-24 12:32                               ` James
2009-06-24 12:54                                 ` Daniel P. Berrange
2009-06-24 14:31                                   ` Stefano Stabellini
2009-06-24 12:46                           ` Anthony Liguori
2009-06-24 13:02                             ` Daniel P. Berrange
2009-06-24 13:21                               ` Avi Kivity
2009-06-24 13:09                             ` Avi Kivity
2009-06-24 16:22                               ` Jamie Lokier
2009-06-24 16:25                                 ` Avi Kivity
2009-06-24 18:52                                   ` Jamie Lokier
2009-06-24 17:39                                 ` Vincent Hanquez
2009-06-24 18:23                                   ` Filip Navara
2009-06-24 18:41                                     ` Jamie Lokier
2009-06-24 18:42                                     ` Vincent Hanquez
2009-06-24 18:55                                       ` Filip Navara
2009-06-24 18:56                                       ` Jamie Lokier
2009-06-24 13:34                             ` Ian Jackson
2009-06-24 16:09                               ` Jamie Lokier
2009-06-24 14:03                             ` Filip Navara
2009-06-25 19:30                               ` Luiz Capitulino
2009-06-24 14:06                             ` Vincent Hanquez
2009-06-24 14:41                             ` Stefano Stabellini
2009-06-24 14:56                             ` Chris Webb
2009-06-24 19:01                               ` Jamie Lokier
2009-06-24 15:57                             ` Filip Navara
2009-06-24 16:22                               ` Avi Kivity
2009-06-24 16:42                                 ` Filip Navara
2009-06-24 19:05                                 ` Jamie Lokier
2009-06-24 19:24                                   ` Filip Navara
2009-06-24 21:13                                     ` Jamie Lokier
2009-06-24 21:29                                       ` Filip Navara
2009-06-24 21:47                                         ` Jamie Lokier
2009-06-25 13:07                                       ` Stefano Stabellini
2009-06-25 14:55                                         ` Avi Kivity
2009-06-25 15:10                                           ` Anthony Liguori
2009-06-25 15:20                                             ` Avi Kivity
2009-06-25 17:04                                               ` Stefano Stabellini
2009-06-25 18:10                                                 ` Anthony Liguori
2009-06-25 19:03                                                   ` Daniel P. Berrange
2009-06-26  9:00                                                     ` Avi Kivity
2009-06-26  9:10                                                       ` Daniel P. Berrange
2009-06-26  9:16                                                         ` Avi Kivity
2009-06-26  9:44                                                           ` Daniel P. Berrange
2009-06-26 11:41                                                             ` Vincent Hanquez
2009-06-25 18:09                                               ` Anthony Liguori
2009-06-25 18:31                                                 ` Avi Kivity
2009-06-25 19:54                                                   ` Anthony Liguori
2009-06-26  9:12                                                     ` Avi Kivity
2009-06-26 13:21                                                       ` Anthony Liguori
2009-06-26 15:02                                                         ` Anthony Liguori
2009-06-26 17:36                                                           ` Filip Navara
2009-06-26 19:36                                                             ` Anthony Liguori
2009-06-26 20:25                                                               ` Filip Navara
2009-06-28 13:16                                                                 ` Avi Kivity
2009-06-28 17:30                                                                   ` Anthony Liguori
2009-06-28 17:36                                                                     ` Avi Kivity
2009-06-29  9:44                                                                     ` Stefano Stabellini
2009-06-29  9:50                                                                       ` Avi Kivity
2009-06-29 10:09                                                                         ` Stefano Stabellini
2009-06-27  7:03                                                               ` Filip Navara
2009-06-28 12:11                                                           ` Avi Kivity
2009-06-28 13:13                                                           ` Avi Kivity
2009-06-28 17:23                                                             ` Anthony Liguori
2009-06-28 17:34                                                               ` Avi Kivity
2009-06-29  0:42                                                                 ` Anthony Liguori [this message]
2009-06-29  6:04                                                                   ` Avi Kivity
2009-06-29  9:48                                                                     ` Stefano Stabellini
2009-06-29 20:23                                                                     ` Anthony Liguori
2009-06-30  5:37                                                                       ` Avi Kivity
2009-06-30 13:30                                                                         ` Anthony Liguori
2009-06-30 13:51                                                                           ` Stefano Stabellini
2009-06-30 13:52                                                                           ` Avi Kivity
2009-06-30 13:56                                                                             ` Anthony Liguori
2009-06-30 14:03                                                                               ` Luiz Capitulino
2009-06-30 16:05                                                                                 ` Avi Kivity
2009-06-30 18:21                                                                                   ` Anthony Liguori
2009-07-01  8:07                                                                                     ` Avi Kivity
2009-06-29 14:41                                                                   ` Stefano Stabellini
2009-06-29 14:56                                                                     ` Avi Kivity
2009-06-28 17:38                                                               ` Filip Navara
2009-06-26 11:36                                                     ` Vincent Hanquez
2009-06-24 16:00                     ` Jamie Lokier
2009-06-23 16:20             ` Avi Kivity
2009-06-23 17:59             ` Vincent Hanquez
2009-06-23 15:41   ` Blue Swirl
2009-06-23  4:28 ` [Qemu-devel] [PATCH 02/11] QMP: Introduce MONITOR_USE_CONTROL flag Luiz Capitulino
2009-06-23  4:28 ` [Qemu-devel] [PATCH 03/11] QMP: Introduce protocol print functions Luiz Capitulino
2009-06-23 13:45   ` Anthony Liguori
2009-06-23 13:53     ` Eduardo Habkost
2009-06-23  4:28 ` [Qemu-devel] [PATCH 04/11] QMP: Make monitor_handle_command() QMP aware Luiz Capitulino
2009-06-23 13:51   ` Anthony Liguori
2009-06-23 17:25     ` Luiz Capitulino
2009-06-23  4:29 ` [Qemu-devel] [PATCH 05/11] QMP: Introduce control mode chardev handling Luiz Capitulino
2009-06-23  4:29 ` [Qemu-devel] [PATCH 06/11] QMP: Introduce asynchronous events infrastructure Luiz Capitulino
2009-06-23  8:59   ` [Qemu-devel] " Jan Kiszka
2009-06-23 13:31     ` Luiz Capitulino
2009-06-23 10:08   ` Daniel P. Berrange
2009-06-23 10:11     ` Avi Kivity
2009-06-23 14:46     ` Paul Brook
2009-06-23 10:32   ` Daniel P. Berrange
2009-06-23 11:23     ` Avi Kivity
2009-06-23 13:36     ` Luiz Capitulino
2009-06-23 13:48       ` Eduardo Habkost
2009-06-23 13:51         ` Jan Kiszka
2009-06-23 16:34           ` Avi Kivity
2009-06-23 16:47           ` Daniel P. Berrange
2009-06-23  4:29 ` [Qemu-devel] [PATCH 07/11] QMP: Enable simple commands Luiz Capitulino
2009-06-23  4:29 ` [Qemu-devel] [PATCH 08/11] QMP: Port balloon command Luiz Capitulino
2009-06-23  9:42   ` [Qemu-devel] " Avi Kivity
2009-06-23 13:59     ` Anthony Liguori
2009-06-23 16:36       ` Avi Kivity
2009-06-23 16:58         ` Anthony Liguori
2009-06-23 16:59       ` Luiz Capitulino
2009-06-23 18:38         ` Anthony Liguori
2009-06-25 11:27           ` Dor Laor
2009-06-25 19:11             ` Luiz Capitulino
2009-06-26  9:21               ` Avi Kivity
2009-06-26  9:42                 ` Daniel P. Berrange
2009-06-26 11:15                   ` Avi Kivity
2009-06-27 15:58                   ` Luiz Capitulino
2009-06-28 15:52                     ` Avi Kivity
2009-06-28 16:30                       ` Blue Swirl
2009-06-28 17:23                       ` Filip Navara
2009-06-28 17:43                         ` Avi Kivity
2009-06-28 17:51                         ` Blue Swirl
2009-06-28 18:36                           ` Avi Kivity
2009-06-28 22:11                           ` Jamie Lokier
2009-06-25 19:59             ` Anthony Liguori
2009-06-23  4:29 ` [Qemu-devel] [PATCH 09/11] QMP: Port 'info blockstats' command Luiz Capitulino
2009-06-23  9:43   ` [Qemu-devel] " Avi Kivity
2009-06-23  9:59     ` Jan Kiszka
2009-06-23 10:09       ` Avi Kivity
2009-06-23 10:10         ` Jan Kiszka
2009-06-23 14:01   ` [Qemu-devel] " Anthony Liguori
2009-06-23  4:29 ` [Qemu-devel] [PATCH 10/11] QMP: Introduce basic events Luiz Capitulino
2009-06-23  9:46   ` [Qemu-devel] " Avi Kivity
2009-06-23 17:07     ` Luiz Capitulino
2009-06-23 10:06   ` Daniel P. Berrange
2009-06-23  4:30 ` [Qemu-devel] [PATCH 11/11] QMP: Command-line flag to enable control mode Luiz Capitulino
2009-06-23  9:03   ` [Qemu-devel] " Jan Kiszka
2009-06-23 10:04     ` Daniel P. Berrange
2009-06-23 10:11       ` Jan Kiszka
2009-06-23 10:17         ` Avi Kivity
2009-06-23 10:54           ` Jan Kiszka
2009-06-23 11:28             ` Avi Kivity
2009-06-23 11:44               ` Jan Kiszka
2009-06-23 11:51                 ` Avi Kivity
2009-06-23 11:53                   ` Jan Kiszka
2009-06-23 12:01                     ` Avi Kivity
2009-06-23 12:39                       ` Jan Kiszka
2009-06-23 12:46                         ` Avi Kivity
2009-06-23 12:48                         ` Avi Kivity
2009-06-23 11:54                   ` Daniel P. Berrange
2009-06-23 11:48               ` Daniel P. Berrange
2009-06-23 12:25                 ` Avi Kivity
2009-06-23 14:06           ` Anthony Liguori
2009-06-23 10:19         ` Daniel P. Berrange
2009-06-23 11:13           ` Jan Kiszka
2009-06-23 13:59     ` Luiz Capitulino
2009-06-23 14:06       ` Jan Kiszka
2009-06-23 17:27         ` Luiz Capitulino

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