Daysleeper

A poem from the Kingdom of Nouns

Steve Yegge, had written a brilliant post, about Noun centric programming in Javaland. This poem takes the cake:

For the lack of a nail,
    throw new HorseshoeNailNotFoundException("no nails!");

For the lack of a horseshoe,
    EquestrianDoctor.getLocalInstance().getHorseDispatcher().shoot();

For the lack of a horse,
    RidersGuild.getRiderNotificationSubscriberList().getBroadcaster().run(
      new BroadcastMessage(StableFactory.getNullHorseInstance()));

For the lack of a rider,
    MessageDeliverySubsystem.getLogger().logDeliveryFailure(
      MessageFactory.getAbstractMessageInstance(
        new MessageMedium(MessageType.VERBAL),
        new MessageTransport(MessageTransportType.MOUNTED_RIDER),
        new MessageSessionDestination(BattleManager.getRoutingInfo(
                                        BattleLocation.NEAREST))),
      MessageFailureReasonCode.UNKNOWN_RIDER_FAILURE);

For the lack of a message,
    ((BattleNotificationSender)
      BattleResourceMediator.getMediatorInstance().getResource(
        BattleParticipant.PROXY_PARTICIPANT,
        BattleResource.BATTLE_NOTIFICATION_SENDER)).sendNotification(
          ((BattleNotificationBuilder)
            (BattleResourceMediator.getMediatorInstance().getResource(
            BattleOrganizer.getBattleParticipant(Battle.Participant.GOOD_GUYS),
            BattleResource.BATTLE_NOTIFICATION_BUILDER))).buildNotification(
              BattleOrganizer.getBattleState(BattleResult.BATTLE_LOST),
              BattleManager.getChainOfCommand().getCommandChainNotifier()));

For the lack of a battle,
    try {
        synchronized(BattleInformationRouterLock.getLockInstance()) {
          BattleInformationRouterLock.getLockInstance().wait();
        }
    } catch (InterruptedException ix) {
      if (BattleSessionManager.getBattleStatus(
           BattleResource.getLocalizedBattleResource(Locale.getDefault()),
           BattleContext.createContext(
             Kingdom.getMasterBattleCoordinatorInstance(
               new TweedleBeetlePuddlePaddleBattle()).populate(
                 RegionManager.getArmpitProvince(Armpit.LEFTMOST)))) ==
          BattleStatus.LOST) {
        if (LOGGER.isLoggable(Level.TOTALLY_SCREWED)) {
          LOGGER.logScrewage(BattleLogger.createBattleLogMessage(
            BattleStatusFormatter.format(BattleStatus.LOST_WAR,
                                         Locale.getDefault())));
        }
      }
    }

For the lack of a war,
    new ServiceExecutionJoinPoint(
      DistributedQueryAnalyzer.forwardQueryResult(
        NotificationSchemaManager.getAbstractSchemaMapper(
          new PublishSubscribeNotificationSchema()).getSchemaProxy().
            executePublishSubscribeQueryPlan(
              NotificationSchema.ALERT,
              new NotificationSchemaPriority(SchemaPriority.MAX_PRIORITY),
              new PublisherMessage(MessageFactory.getAbstractMessage(
                MessageType.WRITTEN,
                new MessageTransport(MessageTransportType.WOUNDED_SURVIVOR),
                new MessageSessionDestination(
                  DestinationManager.getNullDestinationForQueryPlan()))),
              DistributedWarMachine.getPartyRoleManager().getRegisteredParties(
                PartyRoleManager.PARTY_KING ||
                PartyRoleManager.PARTY_GENERAL ||
                PartyRoleManager.PARTY_AMBASSADOR)).getQueryResult(),
        PriorityMessageDispatcher.getPriorityDispatchInstance())).
      waitForService();

All for the lack of a horseshoe nail.

Using models in your migrations

When, you are coding data migrations, and decide to use model classes in your migrations. You are asking for trouble. Why?

Because, migrations is a fluid thing, and say you have decided to get rid of your model all together,then your migrations would magically start failing. This could be a problem.

Toolamantim, suggests an alternative. Simply redefine your models inside migrations itself:

#  class Product < ActiveRecord::Base; end
# class SoftwareProduct < Product; end
# class CourseProduct < Product; end
#
# def self.up
# add_column :products, :position, :integer
# Product.reset_column_information
#
# # Set default list orders
# SoftwareProduct.find(:all).inject(0) do |i,p|
# p.update_attribute(:position, i)
# i+1
# end
# CourseProduct.find(:all).inject(0) do |i,p|
# p.update_attribute(:position, i)
# i+1
# end
# end
#
# def self.down
# remove_column :products, :position
# end

Scaling rails

Scaling isn't easy, it never was. Its not easy with any dynamic language. So, twitter as a rails application is facing some issues of scaling. So while I was sleeping peacefully, a war was going on, in the community. Alex, the twitter developer shares his thoughts, http://www.radicalbehavior.com/5-question-interview-with-twitter-developer-alex-payne/ and DHH retorts back, and criticizes arms-crossed approach, http://www.loudthinking.com/arc/000608.html.

So, what shall a rails developer learn from this. Well, just the basics that - any fool can code web pages, its not rocket science for sure. But how will he react when problems like these strike him? LiveJournal invented memcached, Google invented GFS, Wikipedia does this by aggressive caching. You can't get a out of box, scaling solution. This is the precise reason, Why I have been adamant about hiring people, who know ruby better, who can dig into the internals and come up with shiny code.

Dr Nic, comes with a solution, http://drnicwilliams.com/2007/04/12/magic-multi-connections-a-facility-in-rails-to-talk-to-more-than-one-database-at-a-time/, which is not exactly the same. But lets see. Oh and dev.rubyonrails.org is a python page, which had same problem with trac.

require 'money'

From environment.rb:

 require 'money' 

Isn't it amusing?