Change gnome3's wallpaper from a random one in a directory

change-wallpaper

#!/usr/bin/python3

import os
import random
import subprocess
import sys
import urllib.request, urllib.parse, urllib.error

from os.path import isfile, join

if len(sys.argv) == 1:
    raise RuntimeError("No wallpaper path")

path = sys.argv[1]
wallpapers = [f for f in os.listdir(path) if isfile(join(path, f))]

wallpaper = random.choice(wallpapers)
wallpaper = urllib.parse.quote(join(path, wallpaper))

subprocess.check_call(["/usr/bin/gsettings", "set", "org.gnome.desktop.background", "picture-uri", "file://{}".format(wallpaper)])
subprocess.check_call(["/usr/bin/gsettings", "set", "org.gnome.desktop.screensaver", "picture-uri", "file://{}".format(wallpaper)])

crontab

*/10 * * * * DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus DISPLAY=:0 ~/.local/bin/change-wallpaper /usr/share/wallpapers

gnome-background-change.service

[Unit]
Description=Rotate GNOME background
 
[Service]
Type=oneshot
Environment=DISPLAY=:0
Environment=DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
ExecStart=~/.local/bin/change-wallpaper /usr/share/wallpapers
 
[Install]
WantedBy=basic.target

gnome-background-change.timer

[Unit]
Description=Rotate GNOME wallpaper timer
 
[Timer]
OnCalendar=*:0/10
Persistent=true
Unit=gnome-background-change.service
 
[Install]
WantedBy=gnome-background-change.service

systemd-usage

  systemctl --user enable gnome-background-change.timer                  
  systemctl --user start gnome-background-change.timer