Re: [Libguestfs] [libnbd PATCH] copy: Write progress to stderr, not /dev/tty
On Mon, Sep 05, 2022 at 11:01:52AM +0200, Laszlo Ersek wrote:
On 09/02/22 21:53, Eric Blake wrote:
> On Fri, Sep 02, 2022 at 06:58:53PM +0100, Richard W.M. Jones wrote:
>> On Fri, Sep 02, 2022 at 10:25:38AM -0500, Eric Blake wrote:
>>> dd writes progress messages to stderr, with no complaints. Having
>>> nbdcopy open /dev/tty instead of reusing stderr to write messages
>>> litters the output of a terminal during an interactive 'make
check',
>>> which is rather distracting, even though that test also ran a second
>>> copy using a different fd for inspecting the output.
>>>
>>> Fixes: 1df1b05a ("New nbdcopy tool", v1.3.8)
>>
>> ACK
>>
>> Thanks for looking at this,
>
> Now in as d4d4e70d
>
How does this affect the situation described in
<https://bugzilla.redhat.com/show_bug.cgi?id=2115621>?
I feel like we should add a comment there, noting that commit d4d4e70d
changes the behavior described previously. I'm unsure about the
specifics though.
I didn't mention the progress bar in my brain dumps in that bug, but
that was indeed yet another quirk of virt-v2v output. The progress
bar (only) went to /dev/tty, for no particular reason. This leads to
odd effects:
$ virt-v2v -i disk /var/tmp/fedora-35.img -o null >& /dev/null
█ 100% [****************************************]
(See also the output when you run make check in virt-v2v)
After this change to nbdcopy it goes to stderr so will be mixed in
with the other debug messages.
We probably want the progress bar to be either suppressed or changed
_if_ debugging is enabled. eg. We could change it to be XX/100
instead of a "graphical" bar. Or just get rid of the -p flag.
If debugging is disabled it's unclear if the progress bar really
should be going to stderr, or to stdout with the other normal status
messages, but this is still an improvement vs /dev/tty.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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