Normal tarsnapper output goes to stderr instead of stdout

[Haprog]

When I run

tarsnapper -c /usr/local/etc/tarsnapper.conf make

I get output like

Creating backup mail: mybackupjob-20150610-092951
3 backups are matching
0 of those can be deleted

I would like to suppress normal output like this (which should be stdout) when I run tarsnapper using cron so that I only get email from cron when there is an error (something output to stderr)

So I tried:

tarsnapper -c /usr/local/etc/tarsnapper.conf make >/dev/null

But I still get the same output! I figured only when I redirect using 2>/dev/null I get rid of this output so tarsnapper seems to output this normal output to stderr which is a bug in my opinion. Only errors should be output to stderr and everything else to stdout.

I'm running on Ubuntu 15.04 using tarsnapper installed with easy_install.

[miracle2k]

The Python log library is used, and this is it's default behaviour, because I believe the standard assumption is indeed that messages (error or otherwise) go to stderr, whereas stdout is for data.

This way, when you do convert file.png > out.png, you get log messages on the console and the data in the file.

Of course, tarsnapper does not have any actual "data".

Still, I would lean towards a "log level" option instead, where for running in cron you could simply disable messages that aren't errors.

[Haprog]

Well I think either

1. the non-error output should go to stdout and errors to stderr (then it would be easy to redirect both separately wherever you want) or
2. we need some options/parameters that allow to disable non-error output only and possibly an additional option that allows appending all messages (non-errors and errors) to a logfile while outputting only errors.

I think it would just add unnecessary complexity to implement number 2 (more parameters), because stdout and stderr are already easy to work with and why not use stdout for non-error messages when it's not used for anything else?

[miracle2k]

A --quiet flag is pretty simple to do, and I have a preference for it, since it is pretty standard.

Having said that, maybe it deserves reconsidering what "standard" output is vs what is a log message. Anyway, I don't want to overthink this. If you want to submit a pull request I'm fine with either.

See also: http://stackoverflow.com/questions/2302315/how-can-info-and-debug-logging-message-be-sent-to-stdout-and-higher-level-messag