Re: [Qemu-devel] [PATCH 01/11] QMP: Introduce specification file

[Anthony Liguori <aliguori@us.ibm.com>]

Avi Kivity wrote:
>
> An RPC makes it a lot easier for clients to parse, there's no need for 
> a regular expression per command, or to bother with line continuations 
> etc.  You just focus on the data.
>
> We have an opportunity to make a clean break, let's make use of it.

If we structure things internally correctly, by having a flow that 
basically looks like:

int <monitor_command>(Monitor *mon, <args>)
{
   // process args
   if (success) {
       monitor_print_data(mon, <highly structured output>);
    } else {
       record_extended_error(<message>);
       return error_code;
    }
}

Then it that works well for both the human monitor and the computer 
monitor.  It's an RPC though.

Should we support other types of RPCs?  I don't know.  I'd think that 
you could create a computer monitor -> jsonrpc bridge easily enough.

If we implement this correctly, then an RPC interface could just be 
another option to see the computer monitor mode implemented as a "module".

>> I don't want to invent Xen-API here and go through that pain in QEMU.
>
> I don't see the parallel.

Xen-API was the "clean break" for Xend.

-- 
Regards,

Anthony Liguori