Rotor

Robot is a build system for Elixir projects. Use it to compile things, run commands or do anything that requires being run when files change.

Wreckers don’t call for backup, they call for cleanup ~!

Usage

A set of paths you want to watch is called a watch group. Each watch group has the following

• name
• a list of paths to watch
• a function, which we’ll call the rotor, that is run everytime any of the files in the paths changes. It should accept one argument (a list of maps, each having info about a file).

Adding watch groups

Rotor.add_group(name, files, rotor_function)

The rotor function is passed info about the list of files that match the paths specified. The rotor function calls other functions actions, that run certain tasks.

paths = ["assets/javascripts/libs/*.js"", "assets/javascripts/*.js"]
Rotor.add_group :javascripts, paths, fn(files)->
  read_files(files)
  |> concat
  |> write_to("priv/static/assets/app.js")
end

Actions

Rotor ships with a few simple actions in the Rotor.Actions module.

• read_files(files) - reads contents of files, and returns files with a property called contents
• copy_files(files, destination_dir) - copies files to destination_dir
• concat(files) - concats contents of files and returns a string
• write_to(contents, output_path) - writes the contents to the file path specified in output path

You can also write your own. Check the “Writing custom actions” section below.

Other stuff

To remove a watch group

Rotor.remove_group(group_name)

To list groups

Rotor.groups

To run a watch group’s rotor forcefully

Rotor.run(group_name)

Examples

paths = ["assets/stylesheets/libs/*.css", "assets/stylesheets/*.css"]
Rotor.add_group :stylesheets, paths, fn(files)->
  read_files(files)
  |> concat
  |> write_to("app.css")
end


paths = ["assets/images/*", "assets/fonts/*"]
Rotor.add_group :images_and_fonts, paths, fn(files)->
  copy_files(files, "priv/static/assets")
end

Writing custom actions

Actions are just functions that accept data and do something.

Checkout coffee-rotor, which provides an action to compile CoffeeScript files.