SketchyBar Lua Plugin

This project wraps the SketchyBar API in LUA. This is done by using kernel level inter-process communication between SketchyBar and the LUA module, such that we do not have to alter the source code of SketchyBar at all. The project is in early development, if you want to see how it can be used have a look at the example in the example folder, which is a fully working sketchybar config in LUA which should work out of the box with the current SketchyBar version.

Feel free to contribute to this repo.

LUA Module

This code in this repository compiles into a lua module which can be required from any lua script.

Install and update it with the command (this will build the lua module from source and place it in $USER/.local/share/sketchybar_lua/):

(git clone https://github.com/FelixKratz/SbarLua.git /tmp/SbarLua && cd /tmp/SbarLua/ && make install && rm -rf /tmp/SbarLua/)

For LUA to actually find the module, it has to reside in a path included in the lua cpath (TODO: Install module into the default lua cpath), e.g.:

package.cpath = package.cpath .. ";/Users/" .. os.getenv("USER") .. "/.local/share/sketchybar_lua/?.so"

The module can then be required in a lua script

local sbar = require("sketchybar")

and used to communicate with SketchyBar.

Important Remarks

Calling shell functions using os.execute or io.popen should be avoided. This is because these functions will block the entire lua event handler thread. Instead use:

sbar.exec(<command>, [Optional: <lua_function>])

where the <command> can be any regular shell command. This function is truly async, which means that the command is executed without blocking the event thread. If you depend on the result of the <command> you can optionally specify a function as a completion handler, which will receive the result of the command as the first argument. Additionally, should the result have a JSON structure, it will be parsed into a LUA table. E.g.:

sbar.exec("sleep 5 && echo TEST", function(result, exit_code)
  print(result)
end)

LUA API

Bar Domain

sbar.bar(<property_table>)

where the <property_table> is a lua table with key value pairs. The possible key-value pairs are the same as stated in the sketchybar documentation.

The shell SketchyBar API uses dots to indicate sub-properties, e.g. icon.y_offset=10 icon.width=50, in this LUA API all dots are substituted by sub-tables, i.e. icon = { y_offset = 10, width = 50 }.

Default Domain

sbar.default(<property_table>)

Add Domain

local item = sbar.add(<"item", "space", "alias">, <optional: name>, <property_table>)
local bracket = sbar.add("bracket", <optional: name>, <member_table>, <property_table>)
local slider = sbar.add(<"slider", "graph">, <optional: name>, <width>, <property_table>)
local event = sbar.add("event", <name>, <optional: NSDistributedNotification>)

The <name> is the identifier of the item, if no identifier is specified, it is generated automatically, such that the local item can be used in the following to target this item with further commands.

Depending on the type there might be additional arguments that can (or must) be supplied e.g. if the type is bracket, the add command takes a list of members as a third argument and the property table as the fourth argument. If the type is event the <property_table> is replaced by an optional NSDistributedNotificationCenter notification name.

Set Domain

item:set(<property_table>)

Subscribe Domain

item:subscribe(<event(s)>, <lua_function>)

where all regular sketchybar events are supported. Events can be supplied as a single string or alternatively as a table of events. The <lua_function> is called when the event occurs and receives one argument, which contains the typical sketchybar environment variables, e.g.

front_app:subscribe("front_app_switched", function(env)
  front_app:set({ label = { string = env.INFO } })
end)

Trigger Domain

sbar.trigger(<event>, <optional: env_table>)

Animate Domain

sbar.animate(<curve>, <duration>, <lua_function>)

where the <curve> and <duration> arguments are equivalent to those found in the sketchybar documentation. The lua function given as a third argument shall now contain all commands belonging to this animation, i.e. all set or bar commands that shall be animated.

Query Domain

local info = item:query()

Regularly the query command would result a JSON containing all the relevant information, here, however, this information is accessible as a LUA table and can be accessed as such, e.g.

local left_padding = front_app:query().icon.padding_left

Push Domain

graph:push(<float_table>)

You can push values to a graph with the push domain. The float values of the table should be between 0 and 1.

Multiple Bars

If you are using muliple sketchybar instances, you can target the lua module to interact with another sketchybar instance by providing the instance name right after requiring the module like this:

sbar = require("sketchybar")
sbar.set_bar_name("bottom_bar")

where bottom_bar is an example bar name.