Introducing "rot" - an ultimate stdout/stderr redirector and rotator written in pure Python

Code tested on Ubuntu 11.10

Let’s start with an example.

p = subprocess.Popen(["spam_program", "-a", "-b", "-c", "100500"],
                     stdout=open('spam_out.log', 'wb'))

Imagine you have a spam_program that emits 20GB to stdout/stderr… This program is one of many (hundreds or even thousands) that your test framework will start.

How can we handle this? The first thought is to redirect to /dev/null, which is nice! Except that the author of spam_program may want to grep through this massive log file.

The other option might be to set up logrotate each time the program is started to rotate this huge file. The disadvantage of this approach is that you have to provide a config file for logrotate and have permissions to restart the daemon—and yes, it’s a daemon…

Or you can simply run the program using rot. :) Rot is a zero-install tool written in Python that requires no configuration.

You can find it here: http://github.com/lvsl/rot

Here is an example of its usage:

$rot --stdout-limit 100M \
     --stdout-count 4    \
     --stdout-file spam.stdout.log \
 -- spammy_program -a -b -c 100500