Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command

[Avi Kivity <avi@redhat.com>]

On 06/28/2009 08:23 PM, Filip Navara wrote:
> On Sun, Jun 28, 2009 at 5:52 PM, Avi Kivity<avi@redhat.com>  wrote:
>    
>> On 06/27/2009 06:58 PM, Luiz Capitulino wrote:
>>      
>>>   So, IMHO both solutions (QMP and JSON) solves the problem and I
>>> would work on either one. I just would like that Anthony and Avi
>>> get in agreement, because the project will fail if it becomes
>>> one more difference between qemu and qemu-kvm.
>>>
>>>        
>> There's no danger of a diverging implementation in this case since no one is
>> proposing to have different monitor protocols.  We just need to find the
>> best protocol.  Anthony's looking for minimal churn for the existing monitor
>> command set and for libvirt, while I am considering the additional effort
>> for new commands and for new clients.
>>      
>
> I'm with Avi on this issue, but I will be happy as long as the
> protocol is precisely described and extensible for future. Moreover I
> believe that converting the current code to use a new function like
> monitor_print_data could be done now even without knowing the exact
> details of the on-wire protocol. The monitor_print_data function could
> be then adjusted to understand the protocol specifics and emit the
> data accordingly.
>    

In terms of implementation, I think we could structure the human and 
machine monitor as follows:

- the human monitor parses a command (with the current parser) and 
generates a dict
- the machine monitor (using a json-like parser) parses its input which 
contains a parameter dict
- the dict is handed off to common code
- common code does something, returns an error code and a return value
- the human monitor prints the return value (with the current printfs)
- the machine monitor packs the return value according to the protocol 
and lets the json-like emitter emit it

So we don't have to duplicate parsers an emitters; instead we have to 
write some accessor functions for generalized values (which can come 
from the human monitor, command line, machine monitor, and maybe config 
file).

-- 
error compiling committee.c: too many arguments to function