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

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

Amit Shah wrote:
> On (Tue) Jan 20 2009 [12:35:23], Jan Kiszka wrote:
>> 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.
> 
> Agreed. However, note that the messages sent via term_printf_async()
> will only be emitted if 'notify <foo> on' is issued. Humans wouldn't
> normally do that.
> 

The scenario I have in mind is a qemu instance managed by libvirt etc. +
a monitor console or some forwarded monitor accedd to a gdb frontend
used to analyse/debug a guest. On the latter interface, the user may not
want to get disturbed by notifications the management tools likes to
receive.

Jan

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