rotate_wallpaper.py

#!/usr/bin/env python3

"""
This assumes you're using either Gnome3 or Unity and have a directory of wallpapers
here:

~/Pictures/Wallpaper

You probably want to set this as a cron to execute at a certain interval:

Every 15 minutes:
$ crontab -e

# Edit this file to introduce tasks to be run by cron.
#
# m h  dom mon dow   command
*/15 *  * * * /home/jorvis/bin/rotate_wallpaper.py

"""
import datetime
import os
import pwd
import random
import subprocess

def main():
    current_user = pwd.getpwuid(os.getuid()).pw_name
    image_directory = "/home/{0}/Pictures/Wallpaper".format(current_user)

    new_image = random.choice(os.listdir(image_directory))
    new_image_path = "{0}/{1}".format(image_directory, new_image)

    cmd = "gsettings set org.gnome.desktop.background picture-uri 'file://{0}'".format(new_image_path)
    run_command(cmd)
    
def run_command(cmd):
    return_code = subprocess.call(cmd, shell=True)
    if return_code != 0:
       raise Exception("ERROR: [{2}] Return code {0} when running the following command: {1}".format(return_code, cmd, datetime.datetime.now()))

if __name__ == '__main__':
    main()