Here is a trick to toggle system tray visibility in Awesome using keyboard shortcut. The reason to do that is pretty simple - it looks ugly in some themes. In my case I don’t like two things about it:

• I didn’t manage to make it transparent which is quite important since I am using transparent tasklist and widgets. I tried wibox.widget.systray.opacity property which doesn’t work as well as setting an alpha channel for beautiful.bg_systray.

• Colors of the apps are very different from theme colors which makes systray look flashy and disturbing:

On the other hand not showing it at all will make interaction with some apps pretty difficult. So having a keyboard shortcut which toggles its visibility sounds like a good solution for the problems mentioned above.

To do it create a systray widget inside awful.screen.connect_for_each_screen function:

awful.screen.connect_for_each_screen(function(s)
    ...
    s.systray = wibox.widget.systray()
    s.systray.visible = false
    ...

Then add it to the the wibox: replace default wibox.widget.systray() by s.systray inside s.mywibox:setup method:

s.mywibox:setup {
    ...
    s.mytasklist, -- Middle widget
    {
        ...
        s.systray
    ...

Almost done, the only thing left is a shortcut, I use mod + =:

awful.key({ modkey }, "=", function ()
    awful.screen.focused().systray.visible = not awful.screen.focused().systray.visible
    end, {description = "Toggle systray visibility", group = "custom"})
)