How to use ActiveSupport::LogSubscriber

my_log_subscriber.rb

require 'active_support/log_subscriber'

module ActiveStorage
  class LogSubscriber < ActiveSupport::LogSubscriber
    def service_upload(event)
      message = event.payload[:something]
      info event, color(message, GREEN)
    end
  end
end

ActiveStorage::LogSubscriber.attach_to :active_storage

module ActiveStorage
  class Service
    def upload
      instrument :upload, key: key, checksum: checksum
    end
    
    private
    def instrument(operation, payload = {}, &block)
      ActiveSupport::Notifications.instrument "service_#{operation}.active_storage", payload
    end
  end
end