Ruby Modules, require, module_function, and Rails

plot.rb

# imagine this lives at app/lib/complicated_data
module ComplicatedData
  def generate_complicated_plot_data(start_date: 30.days.ago, end_date: Date.today, type: nil)
    # implementation
  end
  
  # module_function ensures the method cannot be overridden or extended
  module_function :generate_complicated_plot_data
end

some_data_plot_controller.rb

require 'complicated_data/plot'

class SomeDataPlotController < SomeParentController
  # non-resourceful action that returns JSON
  def get_some_complicated_plot_data
    data = ComplicatedData.generate_complicated_plot_data
    render json: data
  end
  
  def index
  end
  
  def show
  end
end