jnunemaker

Addicted to Stable

Stable? In most developer communities, especially Ruby, stable seems nothing short of a curse word. Everyone seems to be addicted to new. I should know, as I once was. Heck, I even own addictedtonew.com.

Over the past few years, my sentiments have changed. Through my experience maintaining and growing a handful of applications, I have grown to respect and love stability.

This talk is jam packed with everything I have learned about building and growing a production application. Stories of mistakes and victories will abound.

jnunemaker

db.command(BSON::OrderedHash['serverStatus', 1, 'repl', 1])['repl']['sources'].first['syncedTo']['time']

jnunemaker

require 'pp'
require 'rubygems'
require 'mongo'

conn = Mongo::Connection.new
db = conn.db('test')
col = db['test']
col.remove

oid = BSON::ObjectId.new

jnunemaker

# from http://avdi.org/talks/confident-code-rubymidwest-2011/confident-code.html

class NullObject
  def method_missing(*)
    self
  end

  def nil?
    true
  end

jnunemaker

# from http://avdi.org/talks/confident-code-rubymidwest-2011/confident-code.html

opt = {}.fetch(:required_option)
# IndexError: key not found

opt = {}.fetch(:required_option) do
  raise ArgumentError, "Missing option!"
end
# ArgumentError: Missing option!

jnunemaker

TwoDimensionalList      := Object clone
TwoDimensionalList list := List clone

TwoDimensionalList dim  := method(x, y,
  for(i, 1, y,
    self list push(List clone setSize(x))
    self
  )
)

jnunemaker

require 'rubygems'
require 'highline/import'
require 'heroku'
require 'pp'

email = ask('Email: ')
password = ask('Password: ') { |q| q.echo = false }

client = Heroku::Client.new(email, password)

jnunemaker

class UserPresenterTest < Test::Unit::TestCase
  def test_as_json
    user = Factory(:user, {
      :first_name => 'John',
      :last_name  => 'Nunemaker',
      :email      => 'john@doe.com',
    })
    json = UserPresenter.new(user).as_json
    urls = json['urls']

jnunemaker

Posted to the REE Google Group as well: https://groups.google.com/forum/#!topic/emm-ruby/EBkMfFpk40A

A week back I innocently updated Sinatra on an app which in turn updated Rack. Since then, I've had crazy hung passenger processes that just gobble up CPU like it is going out of style.

After spending a few days trying everything I knew to to fix it, today I got help from a friend (Eric Lindvall) and dug in with strace, rbtrace, gdb, and gdb.rb and found the issue. Rack 1.3.0 tests a regex against a URL and it causes things to hang.

jnunemaker

# How we store all time views across the entire system for http://gauge.es.
# All in one document that gets incremented using MongoDB $inc modifier in
# every track. The $inc increments t, year.t, year.month.t, year.month.day.t
# so we get to the day numbers. These are in EST, as we are in EST and these
# stats are just for us. :) Nothing amazing, but thought I would share.
#
# >> pp View.all_time
{
  "_id"   => "all_time",
  "t"     => 502352,