deploy.rb

namespace :delayed_job do
  desc "Start delayed_job process" 
  task :start, :roles => :app do
    run "cd #{current_path}; RAILS_ENV=production script/delayed_job start" 
  end

  desc "Stop delayed_job process" 
  task :stop, :roles => :app do
    run "cd #{current_path}; RAILS_ENV=production script/delayed_job stop" 
  end

  desc "Restart the delayed_job process"
  task :restart, :roles => :app do
    stop
    wait_for_process_to_end('delayed_job')
    start
  end
end

def wait_for_process_to_end(process_name)
  run "COUNT=1; until [ $COUNT -eq 0 ]; do COUNT=`ps -ef | grep -v 'ps -ef' | grep -v 'grep' | grep -i '#{process_name}'|wc -l` ; echo 'waiting for #{process_name} to end' ; sleep 2 ; done"
end