Friday Dev Discussion, May 10 201

gistfile1.txt

Agenda

Overview
  * be sure to think of something you learned this week that you'd like to
    share
  * Discuss three gems:

## bullet (https://github.com/flyerhzm/bullet)

  # Gemfile
  gem 'bullet'

  bundle install

  # config/environments/development.rb
  config.after_initialize do
    Bullet.enable = true
    Bullet.alert = true
    Bullet.bullet_logger = true
    Bullet.console = true
    Bullet.rails_logger = true
  end

  1. Edit app/controllers/admin/users_controller.rb:19
    remove: User.includes(:merchant)

  2. Go to http://localhost:5000/admin/users

  3. Check console to see N+1 query output

  4. If you want to tell what the speed-up is, you need to profile it over a
     bunch of requests (to eliminate caching variability)

  5. Lastly, there are some instances where keeping the N+1 is preferable. On
     admin/bundles, you'll find there is one between bundle and user. Adding it
     back in, however, has the side-effect of making the page *much* slower.
     Check it out for yourself if you want to see it.

## pry (http://pryrepl.org)

  1. gem install pry

  2. Basic stuff:

    cd CodeGenerator
    ls
    $ (or show-source)

    c = CodeGenerator.new
    c.gen<tab>
    wtf?
    show-source CodeGenerator#generate
    c.generate 52

  3. Debugging

    binding.pry
    st test/unit/order_test.rb -n "/equal total minus balance/"

    nesting
    play -l 235

    reload-code

    # remove order.rb:234

    https://github.com/nixme/pry-nav
      - adds simple debugging features (step, next, continue)

## spring (https://github.com/jonleighton/spring)

  1. gem install spring (not needed in the Gemfile)

    psgrep spring

  2. Aliases:

    alias st='spring testunit'
    alias srdm='spring rake db:migrate'
    alias srtps='spring rake test:parallel_with_specs'

  3. Compare:

    time t test/unit/ticket_test.rb
    time st test/unit/ticket_test.rb