The Enterprise Strikes BackThe Ruby Trilogy: Part III

The Enterprise Strikes BackThe Ruby Trilogy: Part III

Burke Libbey@burkelibbey

Stefan Penner@stefanpenner

Burke Libbey@burkelibbey

Stefan Penner@stefanpenner

Burke Libbey@burkelibbey

Stefan Penner@stefanpenner

Overview

• Ruby on the JVM (20m)

• Ruby as Glue (20m)

• Testing Java with RSpec (10m)

• Cloud City (15m)

Ruby Java

+ Productive- Scary

+ Not Scary- Less productive

Ruby in Java

+ Not Scary+ Productive

http://jruby.org

• Full ruby implementation on the JVM

• Access to both ruby and Java libraries

• Can be deployed to existing Java infrastructure

The many flavours of ruby

• MRI (and YARV)

• JRuby

• IronRuby

• MacRuby

• Rubinius

• ...and several more...

java.lang.System.out.println("Hello World")

The Magic Sauce

require 'java'(contains up to 30% midichlorians)

Calling Java from ruby

f = javax.swing.JFrame.newf.getContentPane.add(javax.swing.JLabel.new("Hello World"))close_operation = javax.swing.JFrame::EXIT_ON_CLOSEf.setDefaultCloseOperation(close_operation)f.packf.setVisible(true)

Impedance Mismatch

f = javax.swing.JFrame.new

close_operation = javax.swing.JFrame::EXIT_ON_CLOSEf.setDefaultCloseOperation(close_operation)f.packf.setVisible(true)

Let’s break this down.

f.getContentPane.add(javax.swing.JLabel.new("Hello World"))

Impedance Mismatch

f = javax.swing.JFrame.newf.getContentPane.add(javax.swing.JLabel.new("Hello World"))close_operation = javax.swing.JFrame::EXIT_ON_CLOSEf.setDefaultCloseOperation(close_operation)f.packf.setVisible(true)

getContentPane

“Getters” and “Setters” are non-idiomatic in ruby.

snake_case is generally preferred to CamelCase

Impedance Mismatch

f = javax.swing.JFrame.newf. .add(javax.swing.JLabel.new("Hello World"))close_operation = javax.swing.JFrame::EXIT_ON_CLOSEf.setDefaultCloseOperation(close_operation)f.packf.setVisible(true)

content_pane

JavaBean properties can be accessed like this:

“get” disappears, CamelCase changes to snake_case

Impedance Mismatch

f = javax.swing.JFrame.newf. .add(javax.swing.JLabel.new("Hello World"))close_operation = javax.swing.JFrame::EXIT_ON_CLOSEf. close_operationf.packf. true

content_pane

default_close_operation =

visible =

“set” is replaced by “=”

“setDefaultCloseOperation(x)”becomes

“default_close_operation = x”

Ugliness Abounds

f = javax.swing.JFrame.newf.content_pane.add(javax.swing.JLabel.new("Hello World"))close_operation = javax.swing.JFrame::EXIT_ON_CLOSEf.default_close_operation = close_operationf.packf.visible = true

Namespaces everywhere!

javax.swing. javax.swing. javax.swing.

Ugliness Abounds

f = JFrame.newf.content_pane.add(JLabel.new("Hello World"))close_operation = JFrame::EXIT_ON_CLOSEf.default_close_operation = close_operationf.packf.visible = true

java_import adds classes to a ruby context

java_import 'javax.swing.JFrame'java_import 'javax.swing.JLabel' JFrame.new JLabel.new JFrame::EXIT_ON_CLOSE

100% Rubified™

java_import 'javax.swing.JFrame'java_import 'javax.swing.JLabel'

JFrame.new.tap do |f| f.content_pane.add JLabel.new("Hello World") f.default_close_operation = JFrame::EXIT_ON_CLOSE f.pack f.visible = trueend

Method Rubification™

• In general, CamelCase Java methods can optionally be transliterated to snake case.

Uniform Access PrincipleAll services offered by a module should be available through a uniform notation, which does not betray whether they are implemented through storage or through computation.

- Bertrand Meyer

Two Rules

• Everything's an Object• Objects expose Methods and Only Methods

Method Rubification™

Java

RubySystem.currentTimeMillis()

System.current_time_millis

Method Rubification™

Java

Rubyperson.getName()

person.name

Seriously though, not actually trademarked.

Method Rubification™

Java

Rubyperson.setAge(42)

person.age = 42

Someone shouldget on that.

Method Rubification™

Java person.isJedi()

person.jedi?Ruby

FALSE! TRUE!

Is ruby an acceptable Java?

• Most Java code can literally be written as ruby with few high-level changes.

• A more relaxed type system and syntax often has productivity benefits.

(http://bit.ly/pfNluA)

Exhibit A// interfaces = HashMap{ label => NetworkInterface }Collection c = interfaces.values();Iterator itr = c.iterator();

while(itr.hasNext()) { NetworkInterface interface = itr.next(); if (interface.isLoopback()) { return interface.getDisplayName(); }}

# interfaces = {label => NetworkInterface}interfaces.values.find(&:loopback?).display_name

VS.

Java

Ruby

Exhibit A// interfaces = HashMap{ label => NetworkInterface }Collection c = interfaces.values();Iterator itr = c.iterator();

while(itr.hasNext()) { NetworkInterface interface = itr.next(); if (interface.isLoopback()) { return interface.getDisplayName(); }}

# interfaces = {label => NetworkInterface}interfaces.values.find(&:loopback?).display_name

VS.

Java

Ruby 1 2 3 4 5 6 7

Only 7 characters of syntactic support!

“Are you suggesting I write all my Java in ruby?!”

• Not really...

• JRuby is much slower than Java (doesn’t matter as often as you’d think)

• Ruby’s added expressiveness makes it easier to shoot yourself in the foot.(or, in fact, to lazily clone an infinite number of your feet every planck length between your gun and your target)

• ...but maybe sometimes.

• One possibility:

• Encode high-level logic in expressive and concise ruby code

• Supporting code in fast, safe Java

• Mix and match as appropriate

“Are you suggesting I write all my Java in ruby?!”

Ruby as Glue

• Ruby is great for:

• wiring existing codebases together

• other miscellaneous tasks

PerlThe original

“Swiss Army Knife”

Perl• “glue”

• “duct tape”

• “swiss army knife”

Pretty much mean the same thing.

Perl Ruby

Subcategories of “Glue”

• Wiring stuff together

• Sysadmin tasks

Wiring stuff together

• There’s a lot we could cover here, but:

Nokogiri

• An extremely user-friendly XML library

• fast! (wraps libxml2)

Nokogiri

require 'open-uri'require 'nokogiri'html = open("http://slashdot.org").readdoc = Nokogiri::XML(html)(doc/".story a").each do |link| puts "#{link.text} (#{link.attr('href')})"end

# Britain's Broadband Censors: a Bunch of Students (//yro.slashdot...# ...

Don’t do this.

(Nokogiri::XML(open("http://slashdot.org").read)/".story a").each{|a|puts "#{a.text} (#{a.attr("href")})"}

Sysadmin with Ruby

• Nice system APIs(quite similar to perl’s)

• System provisioning libraries/DSLs

Provisioning systems

• Puppet

• Chef

• Vagrant

Puppet

• Describe system, and puppet sets it up

• Nontrivial, but the general idea is:

• I want mysql

• I want nginx < 0.8

• I want this cron job: “....”

• Go.

http://puppetlabs.com/

Puppetclass postgres-server { package { postgresql-server: ensure => latest } group { postgres: gid => 26 } user { postgres: comment => "PostgreSQL Server", uid => 26, gid => 26, home => "/var/lib/pgsql", shell => "/bin/bash" } service { postgresql: running => true, pattern => "/usr/bin/postmaster", require => package["postgresql-server"] }}

Puppet

• Fantastic for defining a reproducible production environment

Chef

• Same idea as puppet

• Somewhat less powerful

• Slightly more approachable to most ruby developers

http://www.opscode.com/chef/

Chefpackage "sudo" do action :upgradeend

template "/etc/sudoers" do source "sudoers.erb" mode 0440 owner "root" group "root" variables( :sudoers_groups => node['authorization']['sudo']['groups'], :sudoers_users => node['authorization']['sudo']['users'], :passwordless => node['authorization']['sudo']['passwordless'] )end

Puppet Chef

Configuration Language custom ruby

Targeted at production production

“Powerfulness” Lots Mostly lots

Verdict Good Different

Written in ruby ruby

Vagrant

• Uses puppet and/or chef

• End product is a virtual machine for development use

• Consistent system for all developers, per project

Vagrant

• If you use puppet or chef, vagrant lets you test production locally

Suggestions

• As a non-ruby-dev:

• Use puppet

• Consider vagrant

Suggestions

• As a ruby developer:

• Consider chef and puppet, use whichever suits your taste and needs

• Consider vagrant

Databases

In the Real World,

In the Real World,

We have Data

In the Real World,

We have Data

Which lives in Databases

Databases Are Always simple

All our data is

ALWAYS in the same DBMS

Reality Check

LuckilyWe have

ODBC + JDBC

LuckilyWe have

ODBC + JDBC

+Ruby

Ruby Gives you Options

• Active Record

• Sequel

• DataMapper

• more

Active RecordDesign pattern coined by Martin Fowler in “Patterns of enterprise application architecture”.

Also, Ruby on Rails’s default ORM.

https://github.com/rails/rails/tree/master/activerecord

• Lots of Power• Lots of Opinion• Might fight with you (for non-standard uses)

Active Record Syntax (Raw)

require 'active_record'

ActiveRecord::Base.establish_connection({ :adapter => 'mysql', :database => 'test_database', :username => 'tester', :password => 'test22'})

connection = ActiveRecord::Base.connection

connection.tables> ['users', 'products', 'ducks', 'oranges']

users = [] connection.execute('SELECT * FROM users').each_hash do |user| users << userend

users> .... array of users, each user as a hash.

users.first> { :id => 1, :username => 'stefan', :password => 'is_super_secure' }

require 'active_record'

ActiveRecord::Base.establish_connection({ :adapter => 'mysql', :database => 'test_database', :username => 'tester', :password => 'test22'})

# class <camel_case_singular_table_name> < ActiveRecord::Baseclass User < ActiveRecord::Base # if the table's name does not fit convention, it can be manually overridden. # table_name :users_tableend

User.first> #<User id: 2, :name => 'stefan', :password => 'is_super_secure' >

User.find(2)> #<User id: 2, :name => 'stefan', :password => 'is_super_secure' >

User.where(:name => 'stefan')> #<User id: 2, :name => 'stefan', :password => 'is_super_secure' >

Active Record Syntax (ORM)

Active Record Syntax (AREL)

User.first> #<User id: 2, :name => 'stefan', :password => 'is_super_secure' >

User.find(2)> #<User id: 2, :name => 'stefan', :password => 'is_super_secure' >

User.where(:name => 'stefan')> #<User id: 2, :name => 'stefan', :password => 'is_super_secure' >

User.where(:name => 'stefan').order('id ASC')> #<User id: 2, :name => 'stefan', :password => 'is_super_secure' >

SequelElegant Full featured database toolkit for ruby.

http://sequel.rubyforge.org/

Supports- ADO, Amalgalite, DataObjects, DB2, DBI, DO, Firebird, ibmdb, Informix, JDBC, MySQL, Mysql2, ODBC, OpenBase, Oracle, PostgreSQL, SQLite3, Swift, and tinytds

• Supports a ton of DBMS’s• DSL• ORM

Sequel Examplerequire "sequel"

# connect to an in-memory databaseDB = Sequel.sqlite

# create an items tableDB.create_table :items do primary_key :id String :name Float :priceend

# create a dataset from the items tableitems = DB[:items]

# populate the tableitems.insert(:name => 'abc', :price => rand * 100)items.insert(:name => 'def', :price => rand * 100)items.insert(:name => 'ghi', :price => rand * 100)

# print out the number of recordsputs "Item count: #{items.count}"

# print out the average priceputs "The average price is: #{items.avg(:price)}"

Sequel ORMrequire "sequel"

# connect to an in-memory databaseDB = Sequel.sqlite

# create an items tableDB.create_table :items do primary_key :id String :name Float :priceend

# create a dataset from the items tableclass Item < Sequel::Model(:items) # associations # validations end

# populate the tableItem.create(:name => 'abc', :price => rand * 100)Item.create(:name => 'def', :price => rand * 100)Item.create(:name => 'ghi', :price => rand * 100)

# print out the number of recordsputs "Item count: #{Item.count}"

# print out the average priceputs "The average price is: #{Item.avg(:price)}"

ready out of the box

Sequel ORM

+jRuby

apparently works?

Sequel ORM

+IRONRuby

Case Study (Access)

• Access (top 2 solutions)

• Solution 1 (Cross Platform)

• jRuby

• JDBC

• HXTT’s driver (www.hxtt.com)

• Sequel

• Solution 2 (Windows Only)

• Ruby

• ADO via WIN32OLE

• Sequel

Case Study (Access)

1. Download jRuby http://jruby.org/

Case Study (Access)

1. Download jRuby http://jruby.org/

2. Install Sequel gem install Sequel

Case Study (Access)

1. Download jRuby http://jruby.org/

2. Install Sequel gem install Sequel

3. Download JDBC Access Driverhttp://www.hxtt.com/access.html

Case Study (Access)

Case Study (Access)require 'rubygems'require 'sequel'require 'sequel/adapters/jdbc'require 'sequel/jdbc_hxtt_adapter'require '../Support/Access_JDBC40.jar'

root = File.expand_path "../../", __FILE__path_to_db = root + "/Support/AccessThemeDemo.mdb"DB = Sequel.connect("jdbc:access:////#{path_to_db}")puts DB.tables

class Notes < Sequel::Model(:Notes)end

class ThemeImages < Sequel::Model(:tbl_ThemeImages)end

class Users < Sequel::Model(:tbl_Users)end

ba-da-bing

But our new appand our old database

have different system requirements.

We Want Isolation

We Want Isolation-_Need

Power by.. Sinatra

used at linkedInhttp://engineering.linkedin.com/44/linkedin-app-end-end-jruby-frontier-and-voldemort

Web DSL

get '/pictures' do ['picture1','picture2','picture2']end

post '/pictures' {}put '/pictures/:id' {}delete '/pictures/:id' {}

sooo... big deal?

RestServer

• any jdbc database into a restful json service

• https://github.com/stefanpenner/restserver

Portability/Bundling

• Warbler

http://github.com/nicksieger/warbler

• single jar/war file

• compiled (if needed)

it’s an app!it’s an app!

Putting it all together (p1)

ScreenShotrdownload:

https://github.com/stefanpenner/screenshotr/zipball/master

git@github.com:stefanpenner/screenshotr

Sorry, contrived example!

anyways...

Java Gives Us• Portability

Ruby Gives Us• Happiness

ScreenShotr

• screen capture

• GUI

Normally Annoying re: Portability

but thx jRuby

Lets Shoot some Screensrequire 'java'

java_import 'java.awt.Robot'java_import 'java.awt.Toolkit'java_import 'java.awt.Rectangle'java_import 'java.awt.Image'java_import 'java.awt.image.BufferedImage'java_import 'javax.imageio.ImageIO'

screenRect = Rectangle.new(Toolkit.default_toolkit.getScreenSize())capture = Robot.new.createScreenCapture(screenRect)

ImageIO.write(capture,'jpg',java.io.File.new('some_tmp_file.jpg'))

Hold UP

Hold UPjava_import ?

Hold UPjava_import ?

why not require?

Hold UPjava_import ?

why not require?requiring classes just makes them discoverable later.

Hold UPjava_import ?

why not import?

why not require?requiring classes just makes them discoverable later.

Hold UPjava_import ?

why not import?Rake defines import

why not require?requiring classes just makes them discoverable later.

Hold UPjava_import ?

why not import?Rake defines import

why not require?requiring classes just makes them discoverable later.

weird...

And fill some clipboards

require 'java'

java_import 'java.awt.Toolkit'java_import 'javax.imageio.ImageIO'

ss = StringSelection.new(public_url) Toolkit.getDefaultToolkit().getSystemClipboard().setContents(ss, nil)

upload to servergem install rest-client

require 'rubygems'

require 'rest-client'

RestClient.post('http://../resource', :file => File.new('path/to/file'))

upload to servergem install rest-client

require 'rubygems'

require 'rest-client'

RestClient.post('http://../resource', :file => File.new('path/to/file'))

<Insert Segue Here>

...and Vice Versa

• We’ve done a lot of calling Java from ruby.

• The reverse is possible as well.

...and Vice Versa

http://en.wikipedia.org/wiki/Jruby

import org.jruby.embed.InvokeFailedException;import org.jruby.embed.ScriptingContainer;

// ...ScriptingContainer container = new ScriptingContainer();container.runScriptlet("puts \"That's no Moon\"");

“i find your lack of tests disturbing.”

Testing Java with Ruby

Testing Java with Ruby

• JtestR is wonderful

• Includes most of ruby’s leading testing libraries

• supports ant and maven

• easy to add to a project

• takes advantage of jruby/java bridge

JtestR Installation

• Download jarfile from jtestr.codehaus.org

• Add to classpath

• Add a task to maven/ant

• Create tests in ./test or ./spec

• Run task

import java.util.HashMap

describe "An empty", HashMap do before :each do @hash_map = HashMap.new end

it "accepts new entries" do @hash_map.put "foo", "bar" @hash_map.get("foo").should == "bar" end

it "returns a keyset iterator that throws an exception on next" do proc do @hash_map.key_set.iterator.next end.should raise_error(java.util.NoSuchElementException) endend

Example!

“i saw a city in the clouds”

MYTH: Ruby can’t scale.

FACT: Ruby scales like a BOSS

FACT: Ruby scales like a BOSS(because it has to)

Fog

• “The Ruby Cloud Services Library”

• Lets you upload to S3, provision instances in EC2, set DNS records in DNSimple...

• ...and much more.

whargarblbgarblgr-garblgragh

Fog

• Chewbacca-approved.

“ ”

whargarblbgarblgr-garblgragh

Fog

• Chewbacca-approved. (chewbaccaproved?)

“ ”

2.5 imperial tons of providers

2.5 imperial tons of providersHeh.( )

Sinatra Example

#config.rurequire './lib/screen_shotr/server'run ScreenShotr::Server.new

require 'sinatra'require 'fog'require 'digest/sha1'

module ScreenShotr class Server < Sinatra::Base def storage #@storage ||= Fog::Storage.new({ # :provider => 'AWS', # :aws_access_key_id => ACCESS_KEY_ID, # :aws_secret_access_key => SECRET_ACCESS_KEY})

@storage ||= Fog::Storage.new({ :local_root => '~/fog', :provider => 'Local' })

def directory storage.directories.find("data").first or storage.directories.create(:key => 'data' ) end

# snip ....

get '/' do "hello, world!"end

post '/picture/create' do file = params[:file] data = file[:tempfile]

#super secure filename filename = file[:filename]

key = Digest::SHA1.hexdigest("super random seed"+Time.now.to_s) key << '.jpg'

file = directory.files.create( :body => data.read, :key => key ) file.public_url or "http://0.0.0.0:9292/picture/#{key}"end

get '/picture/:key' do file = directory.files.get(params[:key]) send_file file.send(:path)end

rackup

and...

Fog Storage: Kind of cool.

Fog Compute: Wicked cool.

Heroku

Cedar Stack (run “anything”)Classic Stack (run rack/rails)

Heroku

Classic Stack (run rack/rails)

$ heroku createCreated sushi.herokuapp.com | git@heroku.com:sushi.git

$ git push heroku master-----> Heroku receiving push-----> Rails app detected-----> Compiled slug size is 8.0MB-----> Launching... done, v1http://sushi.herokuapp.com deployed to Heroku

Heroku

$ cat Procfileweb: bundle exec rails server -p $PORTworker: bundle exec rake resque:work QUEUE=*urgentworker: bundle exec rake resque:work QUEUE=urgentclock: bundle exec clockwork clock.rb

$ heroku scale web=4 worker=2 urgentworker=1 clock=1Scaling processes... done

Cedar Stack (run “anything”)

Ruby, Node.js,Clojure, Java, Python, and Scala

“Officially Everything”:

“help me ruby... you’re my only hope!”“help me ruby...

you’re my only hope!”

“good... the force is strong with you.

a powerful rubyist you will become.”

Thanks!