Re: [linux-lvm] lvcreate and lvremove --quiet option is not quiet

[Ray Morris <support@bettercgi.com>]

>  My general scripting philosophy is that automation scripts that 
> do not have errors should not generate output that will cause cron 
> to send an email.

> So... I grabbed the source code and started nosing around.

So we'll look forward to seeing your patches I hope?
It does seem logical that it shouldn't produce informational
messages on stdout with --quiet.

As to the first part, that got me thinking about the general rule.
Is it generally agreed that commands which do not have errors "should 
not generate output" or that commands which do not have ERRORs "should
not generate output on standard ERROR?

The OP said that these messages are on stdout, not stderr.  I'm
kind of thinking that's right. No errors, nothing on standard error.
If using --quiet, then no standard output.  If lacking a quiet option, 
then cron jobs should redirect stdout to /dev/null, sending mail if 
there are errors on stderr.  Thoughts?
-- 
Ray Morris
support@bettercgi.com

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On Mon, 14 Feb 2011 09:46:05 -0600
Jeff <jlar310@gmail.com> wrote:

> Background: I am using lvm snapshots in a backup script. My general
> scripting philosophy is that automation scripts that do not have
> errors should not generate output that will cause cron to send an
> email.
> 
> I am using Ubuntu 10.04 with lvm2.02.54-1ubuntu4.
> 
> Even with the --quiet option I get "Logical volume <name> created" on
> stdout with lvcreate and "Logical volume <name> successfully removed"
> with lvremove.
> 
> So... I grabbed the source code and started nosing around. In
> lv_manip.c, I find that these messages are produced with a call to the
> function log_print. log_print is a macro (in log.h) for
> LOG_LINE(_LOG_WARN, args). So it looks like the logging system sees
> these messages as warnings and is printing them even though verbosity
> is turned down as far as possible. In addition to --quiet on the
> command line, I have verbose = 0 in lvm.conf which according to the
> man page "should produce no output".
> 
> >From my point of view, lv_manip.c should be calling the log_info
> >macro
> for these messages and not log_print, thus giving the user control
> over the output as advertised by the documentation. Disclaimer: I did
> not dig into the source code far enough to be assured that log_info
> will generated the proper results, but it certainly appears on the
> surface to be the right option.
> 
> I also downloaded the latest source tarball (2.0.2.84) and the
> situation appears to be the same.
> 
> Jeff
> 
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