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Date: Fri, 26 Jun 2009 12:00:54 +0300
From: Avi Kivity <avi@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 01/11] QMP: Introduce specification file
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To: "Daniel P. Berrange" <berrange@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>

On 06/25/2009 10:03 PM, Daniel P. Berrange wrote:
> On Thu, Jun 25, 2009 at 01:10:36PM -0500, Anthony Liguori wrote:
>    
>> Stefano Stabellini wrote:
>>      
>>> Clearly I agree with Avi.
>>> I am thinking for example that we could use the RPC protocol directly
>>>        
>> >from Xend and I am sure other people will find it useful too.
>>      
>>>
>>>        
>> But you can also use QMP from Xend.  In fact, it should be pretty easy
>> to convert the current code in Xend to use QMP.
>>      
>
> AFAIK, the current XenD code doesn't talk to the QEMU monitor at all,
> instead having a add-on to QEMU code which pulls info from XenStored.
> That doesn't alter your point though, it would be pretty easy to make
> XenD talk to the proposed QMP monitor if desired.
>    

All it takes is implementing QMP, and an emitter/parser for each qemu 
command.  On the other hand, things like xml-rpc require around one line 
of code in Python per command.

Let's turn this around.  IIRC libvirt uses an RPC interface for its 
clients.  How would you estimate the effort to port this interface to 
QMP, and adapt all its clients?

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.