Start and Stop tasks for resque workers and resque scheduler with capistrano deploy hook (without God)

deploy.rb

after "deploy:symlink", "deploy:restart_workers"
after "deploy:restart_workers", "deploy:restart_scheduler"

##
# Rake helper task.
# http://pastie.org/255489
# http://geminstallthat.wordpress.com/2008/01/27/rake-tasks-through-capistrano/
# http://ananelson.com/said/on/2007/12/30/remote-rake-tasks-with-capistrano/
def run_remote_rake(rake_cmd)
  rake_args = ENV['RAKE_ARGS'].to_s.split(',')
  cmd = "cd #{fetch(:latest_release)} && #{fetch(:rake, "rake")} RAILS_ENV=#{fetch(:rails_env, "production")} #{rake_cmd}"
  cmd += "['#{rake_args.join("','")}']" unless rake_args.empty?
  run cmd
  set :rakefile, nil if exists?(:rakefile)
end

namespace :deploy do
  desc "Restart Resque Workers"
  task :restart_workers, :roles => :db do
    run_remote_rake "resque:restart_workers"
  end

  desc "Restart Resque scheduler"
  task :restart_scheduler, :roles => :db do
    run_remote_rake "resque:restart_scheduler"
  end
end

resque.rake

# Start a worker with proper env vars and output redirection
def run_worker(queue, count = 1)
  puts "Starting #{count} worker(s) with QUEUE: #{queue}"
  ops = {:pgroup => true, :err => [(Rails.root + "log/workers_error.log").to_s, "a"], 
                          :out => [(Rails.root + "log/workers.log").to_s, "a"]}
  env_vars = {"QUEUE" => queue.to_s}
  count.times {
    ## Using Kernel.spawn and Process.detach because regular system() call would
    ## cause the processes to quit when capistrano finishes
    pid = spawn(env_vars, "rake resque:work", ops)
    Process.detach(pid)
  }
end

# Start a scheduler, requires resque_scheduler >= 2.0.0.f
def run_scheduler
  puts "Starting resque scheduler"
  env_vars = {
    "BACKGROUND" => "1",
    "PIDFILE" => (Rails.root + "tmp/pids/resque_scheduler.pid").to_s,
    "VERBOSE" => "1"
  }
  ops = {:pgroup => true, :err => [(Rails.root + "log/scheduler_error.log").to_s, "a"],
                          :out => [(Rails.root + "log/scheduler.log").to_s, "a"]}
  pid = spawn(env_vars, "rake resque:scheduler", ops)
  Process.detach(pid)
end

namespace :resque do
  task :setup => :environment

  desc "Restart running workers"
  task :restart_workers => :environment do
    Rake::Task['resque:stop_workers'].invoke
    Rake::Task['resque:start_workers'].invoke
  end
  
  desc "Quit running workers"
  task :stop_workers => :environment do
    pids = Array.new
    Resque.workers.each do |worker|
      pids.concat(worker.worker_pids)
    end
    if pids.empty?
      puts "No workers to kill"
    else
      syscmd = "kill -s QUIT #{pids.join(' ')}"
      puts "Running syscmd: #{syscmd}"
      system(syscmd)
    end
  end
  
  desc "Start workers"
  task :start_workers => :environment do
    run_worker("*", 2)
    run_worker("high", 1)
  end

  desc "Restart scheduler"
  task :restart_scheduler => :environment do
    Rake::Task['resque:stop_scheduler'].invoke
    Rake::Task['resque:start_scheduler'].invoke
  end

  desc "Quit scheduler"
  task :stop_scheduler => :environment do
    pidfile = Rails.root + "tmp/pids/resque_scheduler.pid"
    if !File.exists?(pidfile)
      puts "Scheduler not running"
    else
      pid = File.read(pidfile).to_i
      syscmd = "kill -s QUIT #{pid}"
      puts "Running syscmd: #{syscmd}"
      system(syscmd)
      FileUtils.rm_f(pidfile)
    end
  end

  desc "Start scheduler"
  task :start_scheduler => :environment do
    run_scheduler
  end

  desc "Reload schedule"
  task :reload_schedule => :environment do
    pidfile = Rails.root + "tmp/pids/resque_scheduler.pid"

    if !File.exists?(pidfile)
      puts "Scheduler not running"
    else
      pid = File.read(pidfile).to_i
      syscmd = "kill -s USR2 #{pid}"
      puts "Running syscmd: #{syscmd}"
      system(syscmd)
    end
  end
end