Setting up a singleton for bit_analytics in a Rails application

cohort.rb

require "singleton"

class Cohort

  include Singleton

  def self.instance
    @@instance ||= new.db
  end

  def host_url
    @host_url ||= ENV["COHORT_HOST_URL"] || "localhost"
  end

  def port
    @port ||= ENV["COHORT_PORT"] || 6379
  end

  def db
    @db ||= BitAnalytics
            .new({ :host => host_url, :port => port })
            .tap do |e|
      e.send(:define_singleton_method, :state) { "Active" }
      e.mark_event("system:start", Time.now.utc.to_i)
    end
  rescue Object => exception
    @db = OpenStruct.new({ :state => "Inactive", :error => exception })
  end

  def reload!
    @db = nil
  end
end