Class: MiniScheduler::Manager::Runner

Inherits:
Object
  • Object
show all
Defined in:
lib/mini_scheduler/manager.rb

Instance Method Summary collapse

Constructor Details

#initialize(manager) ⇒ Runner

Returns a new instance of Runner.



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# File 'lib/mini_scheduler/manager.rb', line 8

def initialize(manager)
  @stopped = false
  @mutex = Mutex.new
  @queue = Queue.new
  @manager = manager
  @hostname = manager.hostname

  @recovery_thread =
    Thread.new do
      while !@stopped
        sleep 60

        @mutex.synchronize do
          repair_queue
          reschedule_orphans
          ensure_worker_threads
        end
      end
    end

  @keep_alive_thread =
    Thread.new do
      while !@stopped
        @mutex.synchronize { keep_alive }
        sleep(@manager.keep_alive_duration / 2)
      end
    end

  ensure_worker_threads
end

Instance Method Details

#attempts(max_attempts) ⇒ Object 



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# File 'lib/mini_scheduler/manager.rb', line 211

def attempts(max_attempts)
  attempt = 0
  begin
    yield
  rescue StandardError
    attempt += 1
    raise if attempt >= max_attempts
    sleep Random.rand
    retry
  end
end

#current_worker_thread_id ⇒ Object 



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# File 'lib/mini_scheduler/manager.rb', line 93

def current_worker_thread_id
  Thread.current[:mini_scheduler_worker_thread_id]
end

#enq(klass) ⇒ Object 



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# File 'lib/mini_scheduler/manager.rb', line 199

def enq(klass)
  @queue << klass
end

#ensure_worker_threads ⇒ Object 



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# File 'lib/mini_scheduler/manager.rb', line 60

def ensure_worker_threads
  @threads ||= []
  @threads.delete_if { |t| !t.alive? }
  (@manager.workers - @threads.size).times { @threads << Thread.new { worker_loop } }
rescue => ex
  MiniScheduler.handle_job_exception(
    ex,
    message: "Error during MiniScheduler ensure_worker_threads",
  )
end

#hostname ⇒ Object 



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# File 'lib/mini_scheduler/manager.rb', line 89

def hostname
  @hostname
end

#keep_alive(*ids) ⇒ Object 



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# File 'lib/mini_scheduler/manager.rb', line 39

def keep_alive(*ids)
  @manager.keep_alive(*ids)
rescue => ex
  MiniScheduler.handle_job_exception(ex, message: "Error during MiniScheduler keep_alive")
end

#process_queue ⇒ Object 



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# File 'lib/mini_scheduler/manager.rb', line 107

def process_queue
  klass = @queue.deq

  # hack alert, I need to both deq and set @running atomically.
  @running = true

  return if !klass

  failed = false
  start = Time.now.to_f
  info = @mutex.synchronize { @manager.schedule_info(klass) }
  stat = nil
  error = nil

  begin
    info.prev_result = "RUNNING"
    info.current_owner = current_worker_thread_id
    @mutex.synchronize { info.write! }

    if @manager.enable_stats
      stat =
        MiniScheduler::Stat.create!(
          name: klass.to_s,
          hostname: hostname,
          pid: Process.pid,
          started_at: Time.now,
          live_slots_start: GC.stat[:heap_live_slots],
        )
    end

    klass.new.perform
  rescue => e
    MiniScheduler.handle_job_exception(
      e,
      message: "Error while running a scheduled job",
      job: {
        "class" => klass,
      },
    )

    error = "#{e.class}: #{e.message} #{e.backtrace.join("\n")}"
    failed = true
  end

  duration = ((Time.now.to_f - start) * 1000).to_i
  info.prev_duration = duration
  info.prev_result = failed ? "FAILED" : "OK"
  info.current_owner = nil
  if stat
    stat.update!(
      duration_ms: duration,
      live_slots_finish: GC.stat[:heap_live_slots],
      success: !failed,
      error: error,
    )
    MiniScheduler.job_ran&.call(stat)
  end
  attempts(3) { @mutex.synchronize { info.write! } }
ensure
  @running = false

  if defined?(ActiveRecord::Base)
    ActiveRecord::Base.connection_handler.clear_active_connections!
  end
end

#repair_queue ⇒ Object 



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# File 'lib/mini_scheduler/manager.rb', line 45

def repair_queue
  @manager.repair_queue
rescue => ex
  MiniScheduler.handle_job_exception(ex, message: "Error during MiniScheduler repair_queue")
end

#reschedule_orphans ⇒ Object 



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# File 'lib/mini_scheduler/manager.rb', line 51

def reschedule_orphans
  @manager.reschedule_orphans!
rescue => ex
  MiniScheduler.handle_job_exception(
    ex,
    message: "Error during MiniScheduler reschedule_orphans",
  )
end

#set_current_worker_thread_id! ⇒ Object 



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# File 'lib/mini_scheduler/manager.rb', line 97

def set_current_worker_thread_id!
  Thread.current[
    :mini_scheduler_worker_thread_id
  ] = "#{@manager.identity_key}:thread_#{SecureRandom.alphanumeric(10)}"
end

#stop! ⇒ Object 



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# File 'lib/mini_scheduler/manager.rb', line 173

def stop!
  return if @stopped

  @mutex.synchronize do
    @stopped = true

    @keep_alive_thread.kill
    @recovery_thread.kill

    @keep_alive_thread.join
    @recovery_thread.join

    enq(nil)

    kill_thread =
      Thread.new do
        sleep 0.5
        @threads.each(&:kill)
      end

    @threads.each(&:join)
    kill_thread.kill
    kill_thread.join
  end
end

#wait_till_done ⇒ Object 



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# File 'lib/mini_scheduler/manager.rb', line 203

def wait_till_done
  sleep 0.001 while !@queue.empty? && !(@queue.num_waiting > 0)
  # this is a hack, but is only used for test anyway
  # if tests fail that depend on this we are forced to increase it.
  sleep 0.010
  sleep 0.001 while @running
end

#worker_loop ⇒ Object 



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# File 'lib/mini_scheduler/manager.rb', line 71

def worker_loop
  set_current_worker_thread_id!
  keep_alive(current_worker_thread_id)

  while !@stopped
    begin
      process_queue
    rescue => ex
      MiniScheduler.handle_job_exception(
        ex,
        message: "Error during MiniScheduler worker_loop",
      )

      break # Data could be in a bad state - stop the thread
    end
  end
end

#worker_thread_ids ⇒ Object 



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# File 'lib/mini_scheduler/manager.rb', line 103

def worker_thread_ids
  @threads.filter(&:alive?).filter_map { |t| t[:mini_scheduler_worker_thread_id] }
end