[Qemu-devel] Re: [PATCH 1/2] Print asynchronous notifications on request

[Jan Kiszka <jan.kiszka@siemens.com>]

Amit Shah wrote:
> This patch adds the ability to selectively enable asynchronous notifications
> from individual qemu subsystems by a new 'notify' monitor command.
> 
> This is helpful for programs currently parsing monitor output.
> 
> A sample invocation will look like this:
> 
> (qemu)
>     <vnc connection closed>
> (qemu) notify vnc on
>     <vnc connection closed>
> (qemu) # VNC: Closing down connection 127.0.0.1:1
> 
> Notice that the output is prefixed by '#'. Also, it will appear on the
> line that has '(qemu) ' already output on it.

I understand the need, but the result looks a bit ugly, at least to
humans forced to parse it. If you get this while in the middle of type a
command... Moreover, is it impossible that such an async notification is
issued while some other subsystem is already dumping a multi-line
message to the monitor (using multiple prints)? That would be really
problematic.

But if this approach is merged, then I would really say we need
separately configurable monitor terminals, and notify should then only
affect the issuing one. However, my feeling is that a real
machine-dedicated and easily processable channel would be better suited
for this use case.

Jan

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