Rack middleware for Mongo::OperationTimeout

config\application.rb

.....
    config.middleware.insert_after 'Rack::Cache', 'ReconnectMongo'
....

configenvironment.rb

require "reconnect_mongo"

libreconnect_mongo.rb

class ReconnectMongo
  def initialize(app)
    @app = app
  end

  def call(env)
    begin
      User.first
    rescue Mongo::OperationTimeout
      Mongoid.reconnect!
      now = Time.now
      $last_timeout ||= now
      Rails.logger.warn "Mongo::OperationTimeout - reconnecting... Time since last timeout " + (now - $last_timeout).inspect
      $last_timeout = now
    end
    @app.call(env)
  end
end