Add Resque and Resque scheduler rake tasks.

resque.rake

require 'resque/tasks'
require 'resque_scheduler/tasks'

def run_worker(queue, count = 1)
  puts "Starting #{count} Resque worker(s) with QUEUE: #{queue}."
  ops = { pgroup: true, err: [Rails.root.join('log', 'workers_error.log'), 'a'],
          out: [Rails.root.join('log', 'workers.log'), 'a']}
  env_vars = { 'QUEUE' => queue.to_s }

  count.times do
    pid = spawn(env_vars, 'rake resque:work', ops)
    Process.detach(pid)
  end
end

def get_worker_pids(queue)
  # make sure we are only getting workers that are working on our queues
  workers = Resque.workers.select { |w| w.queues.include?(queue) }
  # a hack to grab only workers pids and not accidentally grab capistrano pids
  pids = workers.map { |w| w.to_s.sub /.+:(\d+)[-:].+/, '\1' }
end

def run_scheduler
  puts 'Starting the Resque Scheduler.'
  env_vars = { 'BACKGROUND' => '1',
               'PIDFILE' => Rails.root.join('tmp', 'pids', 'resque_scheduler.pid').to_s,
               'VERBOSE' => '1' }
  ops = { pgroup: true, err: [Rails.root.join('log', 'scheduler_error.log').to_s, 'a'],
          out: [Rails.root.join('log', 'scheduler.log').to_s, 'a'] }
  pid = spawn(env_vars, 'rake resque:scheduler', ops)
  Process.detach(pid)
end

namespace :resque do
  task setup: :environment do
    require 'resque'
    require 'resque_scheduler'

    schedule = Rails.root.join('config', 'resque_schedule.yml')
    Resque.schedule = YAML.load_file(schedule) if schedule.file?
  end

  # the list of worker queues to start and how many
  @workers = [
    { name: 'queue_1', workers: 3 },
    { name: 'queue_2', workers: 4 },
    { name: 'queue_3', workers: 5 }
  ]

  desc 'Restart running workers'
  task restart_workers: :environment do
    Rake::Task['resque:stop_workers'].invoke
    Rake::Task['resque:start_workers'].invoke
  end

  desc 'Stop running workers'
  task stop_workers: :environment do
    queues = @workers.map { |w| w[:name] }
    pids = Array.new
    queues.each do |q|
      pids.concat(get_worker_pids(q))
    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
    @workers.each { |w| run_worker(w[:name], w[:workers]) }
  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.join('tmp', 'pids', 'resque_scheduler.pid')
    if !File.exists?(pidfile)
      puts 'Scheduler not running.'
    else
      pid = File.read(pidfile).to_i
      # check if the scheduler is still running before killing it
      syscmd = "ps aux | grep #{pid} | grep -v grep"
      if system(syscmd)
        syscmd = "kill -s QUIT #{pid}"
        puts "Running syscmd: #{syscmd}"
        system(syscmd)
      end
      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.join('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