# Scottish Ruby Conference 2012 - Edinburgh, UK

Notes and links to the talks I had the pleasure to hear.

It a rough version by now - links to the ScotRubyConf website, Speakerdeck, Lanyard will follow...

## Day 1
1. [Keynote by Mike Lee][day_1_0]
2. [Power Rake by Jim Weirich][day_1_1]
3. [Decoupling Persistence by Piotr Szotkowski][day_1_2]
4. [Hexagonal Raily by Matthew Wynne][day_1_3]
5. [Steven Baker - Maintainable Rails][day_1_4]
6. [Justine Arreche - I am a designer][day_1_5]
7. [Ben Orenstein - Refactoring from good to great][day_1_6]

## Day 2
1. [Keynote by Aaron Patterson][day_2_0]
1. [Someone is wrong - Joseph Wilk][day_2_1]
1. [Just open a Socket by Tyler McMullen][day_2_2]
1. [TDD your command line apps for fun and profit by David Copeland][day_2_3]
1. [Therapeutic Refactoring by Katrina Owen][day_2_4]
1. [Active Record Anti-Patterns by Ethan Gunderson][day_2_5]
1. [Keynote by Dave Thomas][day_2_6]


### Mike Lee [@bmf](https://twitter.com/@bmf) - Diversity, 1st Keynote [day_1_0]

![(Notes)](https://p.twimg.com/Awj3k-mCAAA5Y-g.jpg)
[(Notes)](https://twitter.com/LS_nerdherder/status/218696796568944642/photo/1/large)


***

### Jim Weirich [@jimweirich](http://www.twitter.com/@jimweirich) - Power Rake [day_1_1]

gitimmersion.com

FileList is an Array of Filenames - it's lazy loaded

rake 'file task' is different from normal task
don't follow rake namespace rules with file tasks
new file only created if not existing, or 'out-of-date'

```ruby

    require 'rake/clean'

    # Examples:
    # MYFILES = FileList[ pattern, pattern ]
    # MYFILES.include('images/**/*.png')
    # MYFILES.exclude('*.thumb*')

    # THUMBFILES = MYFILES.pathmap( pattern )
      # images/gem.png --> "thumbs/%n-thumb%x" --> thumbs/gem-thumb.png

    # to convert all png images in all subdirectories under images/
    MYFILES = FileList['images/**/*.png']
    # substitutes dirname images with thumbs (pathmap is not lazy loaded)
    THUMBFILES = MYFILES.pathmap("%{^images,thumbs}d/%n-thumbs%x")

    CLEAN.include(THUMBFILES, "thumbs")   # call 'rake clean' to delete all the THUMBFILES and all files in directory thumbs
    CLOBBER.include("final.png")          # does everything CLEAN does + deletes final.png

    directory "thumbs"    # creates this directory

    # This will build a file task for every image file - beware of large numbers
    THUMBFILES.zip(MYFILES).each do |target , source|
      containing_dir = target.pathmap("%d")
      directory containing_dir
      file target => [containing_dir, source] do
        sh "convert ..."
      end
    end

    file "final.jpg" => THUMBFILES do
      sh "convert #{THUMBFILES} -append final.png"
    end

    task :convert => "final.jpg"

    # call with "rake convert" - won't run again, if filedate of final.png newer than that of all thumbnails

```

An alternative version can be written with rules and lambdas

***

### Piotr Szotkowski [@chastell](https://twitter.com/@chastell) - Decoupling Persistence [day_1_2]

Many examples with Addresses
Book: Person Names around the World

NullDB - Library to stub the DB

Decorators
  Draper
  SimpleDelegator <-- check this out *

Composition over Inheritance
  Forwardable

AOP Aspect-Oriented-Programming
 RCapture (Logging library)
 Make explicit call to persistance methods - or route through persistence layer, every time you data was changed

DCI Data + Context + Interaction

Candy library to persist objects in MongoDB (genius or insane?)

***

### Matt Wynne [@mattwynne](https://twitter.com/@mattwynne) - Hexagonal Rails [day_1_3]
**(with Steve Tooke [@tooky](https://twitter.com/@tooky) and Kevin Rutherford[@kevinrutherford](https://twitter.com/@kevinrutherford))** 

* Why does software development get slower over time?
* modular development vs 'connected' development
* Using 'Metaphors' to design software - and to talk about software
* **Tell, don't ask!**


_Exerpt from the ScotRubyConf Website:_


  
The things that make Rails great in the first few weeks of a new project are precisely what makes it hurt after a few months. Anyone who has worked on a medium-sized Rails app will have experienced pain like:


High coupling, meaning you have to run all your tests all the time to check each change.
Slow tests.
Logic littered in view templates or helper modules.


Changes get more and more expensive to make, and the fun grinds to a halt. How can you stop this from happening? And more importantly, how can you turn around a project that’s already hit this wall of pain?

You need to pull your app away from Rails.

In this practical talk, we describe an architecture for mature Rails applications where the framework becomes a plug-in to your application. With hands-on demonstrations, you’ll learn how to define clear boundaries between your application’s domain and Rails’ domain. Now Rails can stick to doing what it does best – providing the persistence and HTTP stack – and your valuable business logic will be in plain old Ruby objects that are fast to test and easy to reason about.

***

### Steven Baker [@srbaker](https://twitter.com/@srbaker) - Maintainable Rails [day_1_4]

***

### Justine Arreche [@TheElefanta](https://twitter.com/@TheElefanta) - I am a designer (and so are you) [day_1_5]

Book: Bootstrapping Design

12 column grid
  take out groups of 2 for responsiveness
align shapes to grid

Color wheel
Colors stand for emotions (Color theory = some western psylogical stuff)
Contrasting vs Blending Colors
Color Scheme (the easy way): 100% - 50% - 30% - 0% (0 = white)
Color Scheme: Color 1 - Contrasting Color 2 - Color 3 in between 1 and 2 (on the wheel) - grey

Typography
Headlines ~ 24px (or more)
  Text ~ half size in px
    Copytext not that important ~ 9px

horizontal line spacing 22px (or more)

be reasonable about different browsers or special parts of the design - if it does not work in reasonable time, fuck it!

***

### Ben Orenstein [@r00k](https://twitter.com/@r00k) - Refactoring from good to great [day_1_6]

* run your tests
* temp vars --> private methods
* care for short argument lists
* if you have 2 or more variables that have to go together, create a dedicated DataType like Struct (or similar)
* naming is hard - but important
* **Tell, don't ask!**
* Just send an Object a Message!
* use Presenters = Decorators!

     @contact = contact || NullContact.new    # or delegate :name, :to => null_contact...

     class NullContact
      def name
        'no name'
      end

      # ...
    end


* Beware of "God Objects"
    * don't add any more LOC to those 2 or 3 classes, refactor them to become slimmer
    * how to identify them:
        * wc
        * high churn
        * buggy files

_Excerpt from ScotRubyConf website:_


  
Most developers know enough about refactoring to write code that’s pretty good. They create short methods, and classes with one responsibility. They’re also familiar with a good handful of refactorings, and the code smells that motivate them.

This talk is about the next level of knowledge: the things advanced developers know that let them turn good code into great. Code that’s easy to read and a breeze to change.


Topics include:
The Open-Closed Principle
The types of coupling, and their dangers
Why composition is so damn great
A powerful refactoring that Kent Beck calls “deep deep magic”
The beauty of the Decorator pattern
Testing smells, including Mystery Guest and stubbing the system under test
The stuff from the last halves of Refactoring and Clean Code that you never quite got to :)


These topics will be covered solely by LIVE CODING; no slides. We’ll boldly refactor right on stage, and pray the tests stay green. You might even learn some vim tricks as well as an expert user shows you his workflow.




***

### Aaron Patterson [@tenderlove](https://twitter.com/@tenderlove) - Rails Four, 2nd Keynote [day_2_0]

* Threading in MRI
    1. release GVL <---- check what implications come from that *
    2. do CPU operation (outside Ruby it will be done in parall!)
    3. acquire GVL (back to Ruby land)

* Rails Queue for an consistent API
* Streaming in Rails vs. directly opening the Sockets
* autoload vs eager loading to avoid deadlocks
* pre-load ALL the code on startup ?!

Fat Clients - Mobile / JavaScript

Rails.js (tbd) as a better consumer (than Backbone, Ember, ...)

> How to make a Salami

![(Notes)](https://p.twimg.com/Awt66A3CMAAIAap.jpg)
[(Notes)](https://twitter.com/jessabean/status/219404143935238144/photo/1/large)

***

### Joseph Wilk [@josephwilk](https://twitter.com/@josephwilk) - Someone is wrong [day_2_1]

> Knowing Rethoric will make you a better Programmer

The old greeks were reading aloud in the library - to not lose the ability to discuss.
Pathos - Logos - Ethos

Metaphors, Story telling, Passion in the delivery => to form a personal connection
Concede on a small issue -> make your point -> give evidence (past -> present -> future)

being wrong is easy - but also influenced by tense, timing and medium
be wrong in the right way (because the idea was wrong, not the form)

***

### Tyler McMullen [@tbmcmullen](https://twitter.com/@tbmcmullen) - Just open a Socket [day_2_2]

How to build a (better) distributed system

> What is your Message Paradigm? (As 'summary' of all important related questions.)

* Resque = Service - Message Queue - high level - not-general purpose
* RabbitMQ = Service - Multi-Paradigm - available - multi-purpose
* ZooKeeper = Service - Atomic Broadcast - available - non-general purpose
* ZeroMQ = Embedded - Multi-Paradigm - lower-level - Magic - broken community and code
* Sockets = Embedded - Multi-Paradigm - low level

*Future:* (as Tyler sees it)

* (entirely) peer-to-peer 
* minimal configuration
* self-sufficent nodes

Tyler wanted to introduce us to a new open source messaging system, but...
> ... it is hard to do it right - and you have to do it right!

***

### David Copeland [@davetron5000](http://www.twitter.com/@davetron5000) - TDD your command line apps for fun and profit [day_2_3]

> Problem: development environment = production environment

Script 'fullstop' should:
  * clone dotfiles from git
  * symlink to $HOME

use app "methadone" to bootstrap the new app (mkdir, create dirs for tests...)
app "aruba" ~ something with Cucumbers Given/When/Then ...

    # to write bash code in ruby style
    require 'fileutils'
    include FileUtils
    

> Do NOT test with your real $HOME dir
  
    before { set ENV['HOME'] = fake_home }
    after { set ENV['HOME'] = my_home }

_Excerpt from the website:_

I’ve been a programmer for over 15 years, and have cut my teeth on Java, but now write Ruby almost 100% of the time, along with a bit of Scala and other stuff.  I’ve written a book on writing command-line applications in Ruby for the Pragmatic Programmers.

I love clean code, testing, making things work, doing it right, and being realistic about it.

***

### Katrina Owen [@kytrinyx](http://www.twitter.com/@kytrinyx) - Therapeutic Refactoring [day_2_4]

write tests first
deleted unneeded stuff
extract parts into private methods (and clean them up)
clean up the rest

And have fun doing it - and be proud of the result.

Comments have be correct AND valuable

Clean up your dirty code!

Keep your tests fast - to optimize for developer happiness :)

***

### Ethan Gunderson [@ethangunderson](http://www.twitter.com/@ethangunderson) - Active Record Anti-Patterns [day_2_5]

Why care?
  Know your tools
  Maintainability

Leaky Abstractions
  .pluck(:id) <---- check this in the Rails 3.2 API
  change table(users, :bulk => true) <--- use bulk to change many columns in one table!!
  code in a way to avoid "Shotgun Surgeries"

Query Optimization
  Think of data as a stream
  Better use User.friends.find_each do (takes only 1000)
    or User.friends.find_in_batches (creates a scope)
    than User.friends.all do (finds all and creates all AR Objects in memory)
  ... Order.all.includes(&:user) ...??
  Check this gem to find problems: https://github.com/nesquena/query_reviewer

Race Conditions
 validates_uniqueness_of ... create unique_index to be safe - or run in a transaction

Callbacks
  avoid them
  or keep them really simple
  just do one thing
  only change the model itelf - NOT other models!

Law of Demeter
  delegate (even is this also does not feel great)

***

### Dave Thomas [@pragdave](http://www.twitter.com/@pragdave) - Don't label yourself, 3rd Keynote [day_2_6]

walking around in white sox
started with in 98 with Ruby 0.4
got a "Light field camera" from his wife

Labels
  Agile
  a Ruby Programmer
  ...
Labels are static, not wholy descriptive - but defines you, they don't live

practice **Ruby-do** (don't pronounce it Ruby-du - pronounce it Ruby-doh)
japanese character, meaning "Art of Movement"
  There are many ways, not only one.
  There is no "best" - just use the appropriate language/style
  "Good" code is not the only code.
  The only criteria for good code: can it be changed easily?
  care for the little things (clean code, alignement)
  think why you favor some language constructs over others
  practice - e.g. through coding katas
  Confidence comes from practice, not knowledge.
  Distrust:
    experts,
    "best practices"
    Labels

> You are what you do! - Do good!

![(Notes)](https://p.twimg.com/Awt7lOhCMAEn0nU.jpg)
[(Notes)](https://twitter.com/jessabean/status/219404886335434752/photo/1/large)