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

[Avi Kivity <avi@redhat.com>]

On 06/24/2009 03:46 PM, Anthony Liguori wrote:
> There are two questions to resolve.  The first is whether we should 
> continue with the current direction (line-based protocol) or whether 
> we should switch to an RPC.  The second question is which RPC we 
> should use.
>
> I'm not at all convinced that we should switch to an RPC mechanism in 
> the first place.  Perhaps someone could summarize the advantages of 
> doing this because right now, I don't see many.

Less effort for us.

Less effort for clients.

Less documentation effort.

Less likelihood of design and implementation holes (cf. UTF-8, quoting).

Richer data types (arrays, structures, nesting).

> With respect to RPC choice, if we did go that route, I'd be very 
> concerned about using jsonrpc verses a more well established rpc.  I 
> would honestly prefer xml-rpc over jsonrpc.

I agree xml-rpc is a more rational choice than jsonrpc, but I cannot 
find it in my heart to say something nice about xml.  Additionally, XML 
parsers are pretty heavy.

> One reason to choose an RPC is based on the adoption of it.  You want 
> to use something that has a vibrant community with well established 
> client libraries to make writing clients as easy as possible.  Without 
> an active jsonrpc C library, it's hard to argue that jsonrpc has 
> that.  xml-rpc certainly does.

jsonrpc really is a trivial addition over json, and json is pretty 
widespread.  I think I saw a Python jsonrpc implementation.

The important thing however is to reuse, it doesn't really matter what 
we reuse really as long as it's good enough.

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