Assuming a concern that services multiple controllers, there is an issue when it comes to an ActiveJob, because of the parsing sequence, the behaviour is different from running commands in the console, where one would state include GenericMethods before executing any of its methods.

module GenericMethods
  extend ActiveSupport::Concern

  included do

    def create_availabililty(days_ahead)
      ...
    end

  end
end

class SomeJob < ApplicationJob
  queue_as :default

  def perform(days_ahead)
    create_availabililty(days_ahead)
  end
end

placing the include statement at the start will be called on, at that point in processing time, an inexistent method.

Which raises the case for using a callback. the documentation suggests stating around_perform with a private method.

Given there is a yield block, this permits a callback before or after the perform method. What is not clear, to this observer (and the console behaviour muddies the waters), is whether include GenericMethods should be called before or after the yield (i.e. is the method now known to the application and can then be subject to the include before running? or should it be after)

  private
    def around_cleanup
      # Do something before perform
      yield
      # Do something after perform
    end