System-Environment/awesome/widgets/dock/dock.lua

local awful = require("awful")
local gears = require("gears")
local beautiful = require("beautiful")
local wibox = require("wibox")
local naughty = require("naughty")
local dpi     = require("beautiful.xresources").apply_dpi

local HOME = os.getenv('HOME')
local ICON_DIR = HOME .. '/.config/awesome/widgets/dock/icons/'

local rows = { layout = wibox.layout.fixed.vertical }
local menu_items = {
        { name = 'Blender', icon_name = 'blender.svg', command = function() awful.spawn("blender") end },
        { name = 'Krita', icon_name = 'blender.svg', command = function() awful.spawn("krita") end },
}



    --blender:connect_signal("button::press", function() awful.spawn("blender") end)



function update_dock(s)
    -- How do I access and modify dock_items (id = "dock_items") from here?
    -- I can access the dock_bar itself: s.dock_bar,
    -- because it's part of the screen object I get from func arguments.
end

function create_dock(s)
    s.dockheight = (55 *  s.workarea.height)/100
    s.dock_bar = awful.wibar({
        position = "left",
        screen = s,
	x=0, 
	y=s.workarea.height/2 - s.dockheight/2,
        --ontop = true,
	width = dpi(9),
	height = s.dockheight,
	type = "dock"
    })

    local dock_items = {
        layout = wibox.layout.fixed.horizontal,
        id = "dock_items",
	{
	  markup = "Sample Text",
	  widget = wibox.widget.textbox
	},

	  offset = {
             y = 10,
          },
	widget = wibox.container.rotate
    }

    if s.index > 1 and s.dock_bar.y == 0 then
        s.dock_bar.y = screen[1].dock_bar.y
    end

    s.dock_bar:setup {
        layout = wibox.layout.align.horizontal,
        expand = "outside",
        nil, -- Left
        dock_items -- Middle
    }

    -- Add toggling functionalities
    s.docktimer = gears.timer{ timeout = 2 }
    s.docktimer:connect_signal("timeout", function()
        local s = awful.screen.focused()
        s.dock_bar.width = dpi(9)
        if s.docktimer.started then
            s.docktimer:stop()
        end
    end)
    tag.connect_signal("property::selected", function(t)
        local s = t.screen or awful.screen.focused()
	s.dock_bar.width = dpi(38)
        if not s.docktimer.started then
            s.docktimer:start()
        end
    end)

    s.dock_bar:connect_signal("mouse::leave", function()
        local s = awful.screen.focused()
        s.dock_bar.width = dpi(9)
    end)

    s.dock_bar:connect_signal("mouse::enter", function()
        local s = awful.screen.focused()
        s.dock_bar.width = dpi(38)
    end)
end

-- Add dock only to the first screen
--create_dock(screen[1])
awful.screen.connect_for_each_screen(create_dock)

-- Call update_dock when adding/removeing clients
client.connect_signal("list", function(c) update_dock(screen[1]) end)