Module: Kaede::Scheduler

Extended by:
Scheduler
Included in:
Scheduler
Defined in:
lib/kaede/scheduler.rb

Constant Summary collapse

POISON = 
Object.new
DBUS_STOP_TIMEOUT = 
5

Instance Method Summary collapse

Instance Method Details

#epoll_loop(epoll) ⇒ Object 



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# File 'lib/kaede/scheduler.rb', line 76

def epoll_loop(epoll)
  loop do
    epoll.wait do |events, io|
      case io
      when SleepyPenguin::TimerFD
        io.expirations
        _, pid = @timerfds.delete(io.fileno)
        thread = spawn_recorder(pid)
        @recorder_queue.enq(thread)
      when @reload_event
        io.value
        throw :reload
      when @stop_event
        io.value
        $0 = "kaede-scheduler (old #{Time.now.strftime('%F %X')})"
        throw :stop
      else
        abort "Unknown IO: #{io.inspect}"
      end
    end
  end
end

#setup(db) ⇒ Object 



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# File 'lib/kaede/scheduler.rb', line 13

def setup(db)
  @db = db
  setup_signals
  $stdout.sync = true
  $stderr.sync = true
  @recorder_queue = Queue.new
  @recorder_waiter = start_recorder_waiter
  $0 = 'kaede-scheduler'
  puts "Start #{Process.pid}"
end

#setup_signals ⇒ Object 



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# File 'lib/kaede/scheduler.rb', line 26

def setup_signals
  @reload_event = SleepyPenguin::EventFD.new(0, :SEMAPHORE)

  @stop_event = SleepyPenguin::EventFD.new(0, :SEMAPHORE)
  trap(:QUIT) { @stop_event.incr(1) }
end

#spawn_recorder(pid) ⇒ Object 



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# File 'lib/kaede/scheduler.rb', line 159

def spawn_recorder(pid)
  Thread.start do
    begin
      require 'kaede/recorder'
      Recorder.new(Notifier.new).record(@db, pid)
      @db.mark_finished(pid)
    rescue Exception => e
      $stderr.puts "Failed job for #{pid}: #{e.class}: #{e.message}"
      e.backtrace.each do |bt|
        $stderr.puts "  #{bt}"
      end
    end
  end
end

#start ⇒ Object 



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# File 'lib/kaede/scheduler.rb', line 43

def start
  catch(:stop) do
    loop do
      start_epoll
    end
  end
  @recorder_queue.enq(POISON)
  @recorder_waiter.join
end

#start_dbus ⇒ Object 



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# File 'lib/kaede/scheduler.rb', line 99

def start_dbus
  bus = ::DBus.system_bus
  service = bus.request_service(DBus::DESTINATION)

  programs = @db.get_programs(@timerfds.values.map { |_, pid| pid })
  @timerfds.each_value do |tfd, pid|
    _, value = tfd.gettime
    program = programs[pid]
    obj = DBus::Program.new(program, Time.now + value)
    service.export(obj)

    # ruby-dbus doesn't emit properties when Introspect is requested.
    # Kaede manually creates Introspect XML so that `gdbus introspect` outputs properties.
    node = service.get_node(obj.path)
    node.singleton_class.class_eval do
      define_method :to_xml do
        obj.to_xml
      end
    end
  end

  service.export(DBus::Scheduler.new(@reload_event, @stop_event))

  @dbus_main = ::DBus::Main.new
  @dbus_main << bus
  @dbus_thread = Thread.start do
    max_retries = 10
    retries = 0
    begin
      @dbus_main.run
    rescue ::DBus::Connection::NameRequestError => e
      puts "#{e.class}: #{e.message}"
      if retries < max_retries
        retries += 1
        sleep 1
        retry
      end
    end
  end
end

#start_epoll ⇒ Object 



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# File 'lib/kaede/scheduler.rb', line 53

def start_epoll
  epoll = SleepyPenguin::Epoll.new
  epoll.add(@reload_event, [:IN])
  epoll.add(@stop_event, [:IN])

  @timerfds = {}
  @db.get_jobs.each do |job|
    tfd = SleepyPenguin::TimerFD.new(:REALTIME)
    tfd.settime(:ABSTIME, 0, job[:enqueued_at].to_i)
    epoll.add(tfd, [:IN])
    @timerfds[tfd.fileno] = [tfd, job[:pid]]
  end
  puts "Loaded #{@timerfds.size} schedules"
  start_dbus

  catch(:reload) do
    epoll_loop(epoll)
  end
ensure
  epoll.close
  stop_dbus
end

#start_recorder_waiter ⇒ Object 



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# File 'lib/kaede/scheduler.rb', line 33

def start_recorder_waiter
  Thread.start do
    loop do
      recorder_thread = @recorder_queue.deq
      break if recorder_thread.equal?(POISON)
      recorder_thread.join
    end
  end
end

#stop_dbus ⇒ Object 



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# File 'lib/kaede/scheduler.rb', line 141

def stop_dbus
  return unless @dbus_main
  @dbus_main.quit
  begin
    unless @dbus_thread.join(DBUS_STOP_TIMEOUT)
      @dbus_thread.kill
    end
  rescue Exception => e
    $stderr.puts "Exception on DBus thread: #{e.class}: #{e.message}"
    e.backtrace.each do |bt|
      $stderr.puts "  #{bt}"
    end
  end
  @dbus_main = nil
  @dbus_thread = nil
  ::DBus.system_bus.proxy.ReleaseName(DBus::DESTINATION)
end