From: Anthony Liguori <aliguori@us.ibm.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-devel@nongnu.org, armbru@redhat.com, lcapitulino@redhat.com,
qiaonuohan@cn.fujitsu.com, pbonzini@redhat.com,
Amos Kong <akong@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] full introspection support for QMP
Date: Wed, 03 Jul 2013 10:59:35 -0500 [thread overview]
Message-ID: <8761wrk520.fsf@codemonkey.ws> (raw)
In-Reply-To: <20130703150807.GC2784@dhcp-200-207.str.redhat.com>
Kevin Wolf <kwolf@redhat.com> writes:
> Am 02.07.2013 um 19:06 hat Anthony Liguori geschrieben:
>> Eric Blake <eblake@redhat.com> writes:
>> > On 07/02/2013 08:51 AM, Anthony Liguori wrote:
>> >> Amos Kong <akong@redhat.com> writes:
>> >>
>> >>> Introduces new monitor command to query QMP schema information,
>> >>> the return data is a nested dict/list, it contains the useful
>> >>> metadata.
>> >>>
>> >>> we can add events definations to qapi-schema.json, then it can
>> >>> also be queried.
>> >>>
>> >>> Signed-off-by: Amos Kong <akong@redhat.com>
>> >>
>> >> Maybe I'm being too meta here, but why not just return qapi-schema.json
>> >> as a string and call it as day?
>
> I know you don't agree with this, but as I mentioned several times
> before, I think the schema as returned by the introspection functions
> shouldn't contain what a qemu of this version _could_ in theory provide,
> but what this specific build actually _does_ provide. It shouldn't
> include things that are compiled out.
I really don't disagree with you here. I just don't like having two
formats for the schema.
>> > I've also been the one arguing that the additional complexity (an array of
>> > {"name":"str","type":"str","optional":bool"}) is better for libvirt in
>> > that the JSON is then well-suited for scanning (it is easier to scan
>> > through an array where the key is a constant "name", and looking for the
>> > value that we are interested in, than it is to scan through a dictionary
>> > where the keys of the dictionary are the names we are interested in).
>> > That is, the JSON in qapi-schema.json is a nice compact representation
>> > that works for humans, but may be a bit TOO compact for handling via
>> > machines.
>>
>> But adding a bunch of code to do JSON translation just adds a bunch of
>> additional complexity.
>>
>> One reasonable compromise would be:
>>
>> { "command": "foo", "arguments": { "name": "str", "id": "int" },
>> "optional": { "bar": "bool" } }
>
> This assumes that optional vs. mandatory is the only property we ever
> want to describe for fields. Eric's approach is much more future-proof.
> Let's keep the format of qapi-schema.json an implementation detail that
> we can change and extend when necessary.
It's always possible to add another argument that describes additional
information.
For instance:
{ "command": "foo",
"arguments": { "name": "str", "id": "int" },
"optional": { "bar": "bool" },
"defaults": { "bar": false } }
That doesn't mean I think exposing defaults is good, but rather that
it's still possible to do this in a compact form.
Regards,
Anthony Liguori
>
> Kevin
next prev parent reply other threads:[~2013-07-03 16:01 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-19 12:24 [Qemu-devel] [PATCH] full introspection support for QMP Amos Kong
2013-06-19 12:49 ` Amos Kong
2013-06-20 10:16 ` Amos Kong
2013-07-02 16:39 ` Eric Blake
2013-06-21 3:20 ` Luiz Capitulino
2013-07-02 8:37 ` Amos Kong
2013-07-02 14:20 ` Luiz Capitulino
2013-07-16 10:52 ` Amos Kong
2013-07-02 14:51 ` Anthony Liguori
2013-07-02 15:28 ` Eric Blake
2013-07-02 15:39 ` Daniel P. Berrange
2013-07-02 16:44 ` Eric Blake
2013-07-02 17:01 ` Paolo Bonzini
2013-07-02 17:06 ` Eric Blake
2013-07-02 18:27 ` Anthony Liguori
2013-07-04 3:54 ` Amos Kong
2013-07-02 18:21 ` Anthony Liguori
2013-07-02 20:00 ` Paolo Bonzini
2013-07-02 20:08 ` Eric Blake
2013-07-02 20:58 ` Anthony Liguori
2013-07-03 5:52 ` Paolo Bonzini
2013-07-03 12:54 ` Anthony Liguori
2013-07-03 14:45 ` Paolo Bonzini
2013-07-03 16:06 ` Anthony Liguori
2013-07-04 7:53 ` Paolo Bonzini
2013-07-11 13:37 ` Amos Kong
2013-07-02 17:06 ` Anthony Liguori
2013-07-02 17:11 ` Eric Blake
2013-07-02 18:28 ` Anthony Liguori
2013-07-03 15:08 ` Kevin Wolf
2013-07-03 15:59 ` Anthony Liguori [this message]
2013-07-04 7:42 ` Kevin Wolf
2013-07-04 7:55 ` Paolo Bonzini
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