unicorn.rake

# lib/tasks/unicorn.rake
namespace :unicorn do
  config   = Rails.root + 'config/unicorn.rb'
  rackup   = Rails.root + 'config.ru'
  pid_file = Rails.root + 'tmp/pids/unicorn.pid'
  pid = File.exist?(pid_file) ? File.read(pid_file).to_i : nil

  desc 'Starting unicorn process'
  task :start => :environment do
    sh "bundle exec unicorn_rails -D -c #{config} #{rackup}"
  end

  desc 'Graceful shutdown, waits for workers to finish their current request before finishing'
  task :stop => :environment do
    send_signal :QUIT, pid
  end

  desc 'Reexecute the running binary'
  task :restart => :environment do
    send_signal :USR2, pid
  end

  desc 'Reloads config file and gracefully restart all workers'
  task :reload => :environment do
    send_signal :HUP, pid
  end

  desc 'Increment the number of worker processes by one'
  task :increment => :environment do
    send_signal :TTIN, pid
  end

  desc 'Decrement the number of worker processes by one'
  task :decrement => :environment do
    send_signal :TTOU, pid
  end

  def send_signal(signal, pid = nil)
    Process.kill signal, pid unless pid.nil?
  end
end