JRuby and Puma

database_connection.rb

Rails.application.config.after_initialize do
  ActiveRecord::Base.connection_pool.disconnect!

  ActiveSupport.on_load(:active_record) do
    config = ActiveRecord::Base.configurations[Rails.env] ||
    Rails.application.config.database_configuration[Rails.env]
    config['pool'] = ENV['MAX_PUMA_THREADS'] || 16
    ActiveRecord::Base.establish_connection(config)
  end
end

Gemfile.rb

gem "puma", "2.10.2"

Gemfile2.rb

ruby '1.9.3', :engine => 'jruby', :engine_version => '1.7.16'

git-add.sh-session

$ git add Procfile Gemfile
$ git commit -m "prepared app for heroku"

git.sh-session

$ git init
$ git add .
$ git commit -am "first commit"

heroku-create.sh-session

$ heroku create
Creating jkutner-test... done, stack is cedar-14
https://jkutner-test.herokuapp.com/ | https://git.heroku.com/jkutner-test.git
Git remote heroku added

$ git push heroku master
Counting objects: 34, done.
...
-----> Ruby app detected
-----> Compiling Ruby/Rails
-----> Using Ruby version: ruby-1.9.3-jruby-1.7.16
-----> Installing JVM: openjdk7-latest
       Picked up JAVA_TOOL_OPTIONS: -Djava.rmi.server.useCodebaseOnly=true
-----> Installing dependencies using 1.6.3
       Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment
       Picked up JAVA_TOOL_OPTIONS: -Djava.rmi.server.useCodebaseOnly=true
       ...
       Your bundle is complete!
       Gems in the groups development and test were not installed.
       It was installed into ./vendor/bundle
       Bundle completed (16.73s)
       Cleaning up the bundler cache.
-----> Preparing app for Rails asset pipeline
       Running: rake assets:precompile
       Picked up JAVA_TOOL_OPTIONS: -Djava.rmi.server.useCodebaseOnly=true
       I, [2014-12-04T20:09:48.558000 #970]  INFO -- : Writing /tmp/build_4314fe0fe5c1c451df6755a9edded670/public/assets/application-3977927cf8f68a5ebafbe59011904fad.js
       Asset precompilation completed (61.06s)
       Cleaning assets
       Running: rake assets:clean
       Picked up JAVA_TOOL_OPTIONS: -Djava.rmi.server.useCodebaseOnly=true

       WARNING:
       Include 'rails_12factor' gem to enable all platform features
       See https://devcenter.heroku.com/articles/rails-integration-gems for more information.

-----> Discovering process types
       Procfile declares types -> web
       Default types for Ruby  -> console, rake, worker

-----> Compressing... done, 112.5MB
-----> Launching... done, v7
       https://jkutner-test.herokuapp.com/ deployed to Heroku

Verifying deploy... done.
To https://git.heroku.com/jkutner-test.git
   7288c10..7814b0d  master -> master

heroku-open.sh-session

$ heroku open

jruby.sh-session

$ rvm use jruby-1.7.16.1
Using /Users/jkutner/.rvm/gems/jruby-1.7.16

$ ruby -v
jruby 1.7.16 (1.9.3p392) 2014-09-25 575b395 on Java HotSpot(TM) 64-Bit Server VM 1.7.0_51-b13 +jit [darwin-x86_64]

Procfile

web: bundle exec puma -C config/puma.rb

puma.rb

port        ENV['PORT']     || 3000
environment ENV['RACK_ENV'] || 'development'
threads     (ENV["MIN_PUMA_THREADS"] || 0), (ENV["MAX_PUMA_THREADS"] || 16)
preload_app!

puma.sh-session

$ bundle exec puma -C config/puma.rb

rails.sh-session

$ gem install rails -v 4.1.8
...
Successfully installed rails-4.1.8
1 gem installed

$ rails new my_app --database=postgresql
...
Use `bundle show [gemname]` to see where a bundled gem is installed.