Código Saudável => Programador Feliz - Rs on Rails 2010

Código Saudável =>Programador Feliz

[~]$ whoami

@rlm ores

1993-1995

2003-2004

Ruby on Rails

2011 Text

Sua aplicação

ArquiteturaModelosProdução

Model View Controller

Model ControllerView View View View View

class ArticlesController < ActionController::Base def index if params[:user_id].blank? @articles = Article.all else @articles = current_user.articles end endend

ModelDeslogado Logado Controller Controller View View View View View View

class ArticlesController < ActionController::Base def index @articles = Article.all endendclass Users::ArticlesController < ActionContro... def index @articles = current_user.articles.all endend

class UsersControllers < ApplicationController def index @users = User.all endendclass Admin::UsersControllers < ApplicationCont...def index @users = User.all endend

module UsersIndex def index @users = User.all endendclass UsersController < ApplicationController include UsersIndexendclass Admin::UsersControllers < ApplicationController include UsersIndexend

Acoplamento XRepetição de código

“Every piece of knowledgemust have a single,unambiguous, authoritativerepresentation within asystem.” Pragmatic Programmer

Repeat code =Repeat Logic

Não economizar nonúmero de controllers

Cada Controller é uma lógica diferente

DRY não é economizar código, mas manter aslógicas em um lugar só

SkinnyController,Fat Model

Obese Models

MuitasDifícil Manter Responsabilidades DifícilBaixa Coesão Compreender

Sintoma #1 MuitaResponsabilidade

class Account < ActiveRecord::Base validates_numericality_of :amount validates_inclusion_of :currency, :in => %w( us_dollar euro (...)) def convert_to_us_dollar if currency == :us_dollar currency elsif currency == :euro currency * ConversionRate.rate(:dollar,:euro) (...) end end def convert_to_euro if currency == :euro currency elsif currency == :dollar currency * ConversionRate.rate(:euro,:dollar) (...) end endend

composed_of

class Money def initialize(amount, currency) @amount, @currency = amount, currency end def convert_to_us_dollar if currency == :us_dollar @currency elsif currency == :euro @currency * ConversionRate.rate(:dollar,:euro) (...) end end def convert_to_euro if currency == :euro @currency elsif @currency == :dollar @currency * ConversionRate.rate(:euro,:dollar) (...) end end

class Account < ActiveRecord::Base validates_numericality_of :amount validates_inclusion_of :currency, :in => %w( us_dollareuro (...)) composed_of :balance, :class_name =>Money, :mapping => %w( amount currency)end

Mais fácil de manter Responsabilidades (e reutilizar!) divididas Mais simples de APIs menores compreender

Sintoma #2Lógicas repetidas

Lixeira

class Post < ActiveRecord::Base # (...) default_scope where(trashed: false) scope :trashed, where(trashed: true) def trash update_attribute :trashed, true endend

class Comment < ActiveRecord::Base # (...) default_scope where(trashed: false) scope :trashed, where(trashed: true) def trash update_attribute :trashed, true endend

module Trashable extend ActiveSupport::Concern included do default_scope where(trashed: false) scope :trashed, where(trashed: true) end def trash update_attribute :trashed, true endend

class Post < ActiveRecord::Base include Trashableendclass Comment < ActiveRecord::Base include Trashableend

Sintoma #3 “Super Abstração”do Banco de Dados

Models retiram dados do BD

post.comments.sizepost.comments.countpost.comments.length

post.comments.count

SQL (0.3ms) SELECT COUNT(*) FROM `comments`WHERE (`comments`.post_id = 1)

post.comments.length

Comment Load (0.4ms) SELECT `comments`.* FROM`comments` WHERE (`comments`.post_id = 1)

post.comments.size

# File activerecord/lib/active_record/relation.rb, line 84def size loaded? ? @records.length : countend

Active Record é bom!Mas que de olho no banco!

<% comments.each do |comment| %> <% if comment.post %> (...) <% end %><% end %>

Comment Load (0.6ms) SELECT `comments`.* FROM `comments`Post Load (0.4ms) SELECT `posts`.* FROM `posts` WHERE `posts`.ìd` =1 LIMIT 1Post Load (0.2ms) SELECT `posts`.* FROM `posts` WHERE `posts`.ìd` =2 LIMIT 1(...)Post Load (0.2ms) SELECT `posts`.* FROM `posts` WHERE `posts`.ìd` =99 LIMIT 1Post Load (0.2ms) SELECT `posts`.* FROM `posts` WHERE `posts`.ìd`= 100 LIMIT 1

<% comments.each do |comment|%> <% if comment.post_id %> (...) <% end %><% end %>

Comment Load (0.6ms) SELECT `comments`.* FROM`comments`

@comments = Comment.all(:include => :post)

Comment Load (0.7ms) SELECT `comments`.* FROM`comments`Post Load (46.4ms) SELECT `posts`.* FROM `posts` WHERE(`posts`.`id` IN (1,2,(...),100))

Extrair funcionalidades dos modelos: Composed ofEliminar duplicação de lógicas ConcernFicar de olho nas Queries Query Reviewer

Um dia a hora chega ...

Checklist!

AnalyticsException noti erPerformance loggerMonitoramento de ServidorNota A no YSlowDeploy automatizadoBackup

Solução Open SourceSolução via “serviço”

Analytics

Exception Noti er

Performance Logger

Monitoramento de Servidor

Nota Ano YSlow

DeployAutomatizado

git pulltouch tmp/restart.txt

git pulljammittouch tmp/restart.txt

rake db:backupgit pullrake db:migratejammittouch tmp/restart.txt

ps aux | ... | kill ...rake db:backupgit pull(...) rake resque:(...)rake db:migratejammittouch tmp/restart.txt

ps aux | ... | kill ...rake db:backupgit pull(...) rake resque:(...)rake sphinx:rebuildrake db:migratejammit

Mais de uma máquina ?Rollback ?Múltiplos Ambientes

Backup!

Cron + RSync

Teste seu Backup!

Crie um padrão de qualidade !Invista tempo (ou $$ ) em melhorias !Faça e cumpra um checklist

Código bem feito +Aplicação bem monitorada=> Programador Mais Feliz!

Make it work (and writetests to ensure that)Make it awesome(with tests you know that it still works)if you need, make it fast

Rodrigo Flores blog.plataformatec.com @rlmﬂores Perguntas?

ID blog twitterRodrigo Flores blog.plataformatec.com @rlmﬂores Perguntas?

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Código Saudável => Programador Feliz - Rs on Rails 2010

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