Random wallpaper in Awesome WM

rc.lua

-- Sources:
-- * https://wiki.archlinux.org/index.php?oldid=265165#Random_Background_Image
-- * https://wiki.archlinux.org/title/Special:Diff/265909
-- * https://www.reddit.com/r/awesomewm/comments/3r01p1/

-- {{{ Function definitions

-- scan directory, and optionally filter outputs
function scandir(directory, filter)
    local i, t, popen = 0, {}, io.popen
    if not filter then
        filter = function(s) return true end
    end
    print(filter)
    for filename in popen('ls -a "'..directory..'"'):lines() do
        if filter(filename) then
            i = i + 1
            t[i] = filename
        end
    end
    return t
end

-- }}}

-- configuration - edit to your liking
wp_timeout  = 10
wp_path = "/path/to/wallpapers/"
wp_filter = function(s) return string.match(s,"%.png$") or string.match(s,"%.jpg$") end
wp_files = scandir(wp_path, wp_filter)

-- initialize the random generator
math.randomseed(os.time())

-- setup the timer
wp_timer = timer { timeout = wp_timeout }
wp_timer:connect_signal("timeout", function()

  -- get random index
  local wp_index = math.random( 1, #wp_files)

  -- set wallpaper to current index for all screens
  for s = 1, screen.count() do
    gears.wallpaper.maximized(wp_path .. wp_files[wp_index], s, true)
  end

  -- stop the timer (we don't need multiple instances running at the same time)
  wp_timer:stop()

  --restart the timer
  wp_timer.timeout = wp_timeout
  wp_timer:start()
end)

-- initial start when rc.lua is first run
wp_timer:start()

Thanks