Example Unicorn config

unicorn.rb

rails_env = ENV['RAILS_ENV'] || 'production'
rails_root  = `pwd`.gsub("\n", "")
rails_user = ENV['RAILS_USER'] || 'rails'
rails_group = ENV['RAILS_GROUP'] || 'group'

unless rails_env == 'production'
  listen '127.0.0.1:8080'
else
  listen "#{rails_root}/tmp/sockets/unicorn.sock", backlog: 64
end

worker_processes Integer(ENV["WEB_CONCURRENCY"] || 4)
timeout 15
preload_app true

pid         "#{rails_root}/tmp/pids/unicorn.pid"
stderr_path "#{rails_root}/log/unicorn.log"
stdout_path "#{rails_root}/log/unicorn.log"

user(rails_user, rails_group) if rails_env == 'production'

GC.copy_on_write_friendly = true if GC.respond_to?(:copy_on_write_friendly=)

before_fork do |server, worker|
  ActiveRecord::Base.connection.disconnect! if defined? ActiveRecord::Base

  old_pid = "#{rails_root}/tmp/pids/unicorn.pid.oldbin"
  if File.exists?(old_pid) && server.pid != old_pid
    begin
      Process.kill("QUIT", File.read(old_pid).to_i)
    rescue Errno::ENOENT, Errno::ESRCH
      # It's already deeeeaaaaad...
    end
  end
end

after_fork do |server, worker|
  ActiveRecord::Base.establish_connection if defined? ActiveRecord::Base
end