Re: [PATCH 0/5] qmp-shell modifications for non-interactive use

[Damien Hedde <damien.hedde@greensocs.com>]

On 2/22/22 11:31, Daniel P. Berrangé wrote:
> On Tue, Feb 22, 2022 at 10:38:09AM +0100, Damien Hedde wrote:
>>
>>
>> Here I just wanted to propose a simple way to just send a
>> bunch of commands from a source file and stop if something unexpected
>> happens.
>> Only goal is to be able to share a file on the ml and allow people to
>> reproduce easily.
>> We can already redirect the input, but it is almost impossible to see
>> if something failed.
> 
> Yes, I see what you mean. So the problem with using 'socat' or similar
> is that we fill the input with commands and response appear asynchronously,
> so we can't match them up easily. This is actually a problem seen in the
> block I/O tests which just send QMP stuff in a batch.
> 
> While you could do this by invoking socat once for each command, that
> gets silly with the repeated QMP handshake for each command.
> 
> The thing about using qmp-shell is that it does a bunch of extra stuff
> targetted at humans on top, and history tells us it isn't a good idea
> to mix stuff for humans and machines in the same tool/interface.
> 
> How about instead creating a separate 'qmp-send' command that is not
> much more than a "QMP-aware socat".  By which I mean, it just reads
> raw QMP commands from stdin, sends each one to the server, but
> crucially waits for a reply after sending each, and stops on first
> error reponse.

By 'qmp-send' command, you mean another script in scripts/qmp ?
Yes

If we go for another script, I would rather do one with wrap
feature (like your series) to start qemu as well.

--
Damien