From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46740) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UuOfI-0005oy-C6 for qemu-devel@nongnu.org; Wed, 03 Jul 2013 11:08:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UuOfG-0005FH-Hd for qemu-devel@nongnu.org; Wed, 03 Jul 2013 11:08:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44974) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UuOfG-0005F0-9Z for qemu-devel@nongnu.org; Wed, 03 Jul 2013 11:08:14 -0400 Date: Wed, 3 Jul 2013 17:08:07 +0200 From: Kevin Wolf Message-ID: <20130703150807.GC2784@dhcp-200-207.str.redhat.com> References: <1371644677-11041-1-git-send-email-akong@redhat.com> <878v1pqak4.fsf@codemonkey.ws> <51D2F1B3.1080903@redhat.com> <87a9m4j3i7.fsf@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87a9m4j3i7.fsf@codemonkey.ws> Subject: Re: [Qemu-devel] [PATCH] full introspection support for QMP List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: armbru@redhat.com, qemu-devel@nongnu.org, lcapitulino@redhat.com, qiaonuohan@cn.fujitsu.com, pbonzini@redhat.com, Amos Kong Am 02.07.2013 um 19:06 hat Anthony Liguori geschrieben: > Eric Blake writes: > > On 07/02/2013 08:51 AM, Anthony Liguori wrote: > >> Amos Kong 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 > >> > >> 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'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. Kevin