Module: Einhorn::Command

Defined in:
lib/einhorn/command.rb,
lib/einhorn/command/interface.rb

Defined Under Namespace

Modules: Interface

Constant Summary collapse

MAX_SPINUP_INTERVAL =

Unbounded exponential backoff is not a thing: we run into problems if e.g., each of our hundred workers simultaneously fail to boot for the same ephemeral reason. Instead cap backoff by some reasonable maximum, so we don't wait until the heat death of the universe to spin up new capacity.

30.0

Class Method Summary collapse

Class Method Details

.cleanup(pid) ⇒ Object 



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# File 'lib/einhorn/command.rb', line 20

def self.cleanup(pid)
  unless (spec = Einhorn::State.children[pid])
    Einhorn.log_error("Could not find any config for exited child #{pid.inspect}! This probably indicates a bug in Einhorn.")
    return
  end

  Einhorn::State.children.delete(pid)

  # Unacked worker
  if spec[:type] == :worker && !spec[:acked]
    Einhorn::State.consecutive_deaths_before_ack += 1
    extra = " before it was ACKed"
  else
    extra = nil
  end

  case type = spec[:type]
  when :worker
    Einhorn.log_info("===> Exited worker #{pid.inspect}#{extra}", :upgrade)
  when :state_passer
    Einhorn.log_debug("===> Exited state passing process #{pid.inspect}", :upgrade)
  else
    Einhorn.log_error("===> Exited process #{pid.inspect} has unrecgonized type #{type.inspect}: #{spec.inspect}", :upgrade)
  end
end

.cull ⇒ Object 



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# File 'lib/einhorn/command.rb', line 460

def self.cull
  acked = Einhorn::WorkerPool.ack_count
  unsignaled = Einhorn::WorkerPool.unsignaled_count
  target = Einhorn::WorkerPool.ack_target

  if Einhorn::State.upgrading && acked >= target
    Einhorn::State.upgrading = false
    Einhorn.log_info("Upgraded successfully to version #{Einhorn::State.version} (Einhorn #{Einhorn::VERSION}).", :upgrade)
    Einhorn.send_tagged_message(:upgrade, "Upgrade done", true)
  end

  old_workers = Einhorn::WorkerPool.old_workers
  Einhorn.log_debug("#{acked} acked, #{unsignaled} unsignaled, #{target} target, #{old_workers.length} old workers")
  if !Einhorn::State.upgrading && old_workers.length > 0
    Einhorn.log_info("Killing off #{old_workers.length} old workers.", :upgrade)
    signal_all("USR2", old_workers)
  elsif Einhorn::State.upgrading && Einhorn::State.smooth_upgrade
    # In a smooth upgrade, kill off old workers one by one when we have
    # sufficiently many new workers.
    excess = (old_workers.length + acked) - target
    if excess > 0
      Einhorn.log_info("Smooth upgrade: killing off #{excess} old workers.", :upgrade)
      signal_all("USR2", old_workers.take(excess))
    else
      Einhorn.log_debug("Not killing old workers, as excess is #{excess}.")
    end
  end

  if unsignaled > target
    excess = Einhorn::WorkerPool.unsignaled_modern_workers_with_priority[0...(unsignaled - target)]
    Einhorn.log_info("Have too many workers at the current version, so killing off #{excess.length} of them.")
    signal_all("USR2", excess)
  end

  # Ensure all signaled workers that have outlived signal_timeout get killed.
  kill_expired_signaled_workers if Einhorn::State.signal_timeout
end

.decrement ⇒ Object 



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# File 'lib/einhorn/command.rb', line 168

def self.decrement
  if Einhorn::State.config[:number] <= 1
    output = "Can't decrease number of workers (already at #{Einhorn::State.config[:number]}).  Run kill #{$$} if you really want to kill einhorn."
    warn(output)
    return output
  end

  Einhorn::Event.break_loop
  old = Einhorn::State.config[:number]
  new = (Einhorn::State.config[:number] -= 1)
  output = "Decrementing number of workers from #{old} -> #{new}"
  warn(output)
  output
end

.dumpable_state ⇒ Object 



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# File 'lib/einhorn/command.rb', line 201

def self.dumpable_state
  global_state = Einhorn::State.dumpable_state
  descriptor_state = Einhorn::Event.persistent_descriptors.map do |descriptor|
    descriptor.to_state
  end

  {
    state: global_state,
    persistent_descriptors: descriptor_state
  }
end

.full_upgrade(options = {}) ⇒ Object

Parameters:

  • options (Hash) (defaults to: {})

Options Hash (options):

  • :smooth (Boolean) — default: false —

    Whether to perform a smooth or fleet upgrade. In a smooth upgrade, bring up new workers and cull old workers one by one as soon as there is a replacement. In a fleet upgrade, bring up all the new workers and don't cull any old workers until they're all up.



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# File 'lib/einhorn/command.rb', line 416

def self.full_upgrade(options = {})
  options = {smooth: false}.merge(options)

  Einhorn::State.smooth_upgrade = options.fetch(:smooth)
  reload_for_upgrade
end

.full_upgrade_fleet ⇒ Object 



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# File 'lib/einhorn/command.rb', line 427

def self.full_upgrade_fleet
  full_upgrade(smooth: false)
end

.full_upgrade_smooth ⇒ Object 



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# File 'lib/einhorn/command.rb', line 423

def self.full_upgrade_smooth
  full_upgrade(smooth: true)
end

.increment ⇒ Object 



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# File 'lib/einhorn/command.rb', line 159

def self.increment
  Einhorn::Event.break_loop
  old = Einhorn::State.config[:number]
  new = (Einhorn::State.config[:number] += 1)
  output = "Incrementing number of workers from #{old} -> #{new}"
  warn(output)
  output
end

.kill_expired_signaled_workers ⇒ Object 



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# File 'lib/einhorn/command.rb', line 498

def self.kill_expired_signaled_workers
  now = Time.now
  children = Einhorn::State.children.select do |_, c|
    # Only interested in USR2 signaled workers
    next unless c[:signaled] && c[:signaled].length > 0
    next unless c[:signaled].include?("USR2")

    # Ignore processes that have received KILL since it can't be trapped.
    next if c[:signaled].include?("KILL")

    # Filter out those children that have not reached signal_timeout yet.
    next unless c[:last_signaled_at]
    expires_at = c[:last_signaled_at] + Einhorn::State.signal_timeout
    next unless now >= expires_at

    true
  end

  Einhorn.log_info("#{children.size} expired signaled workers found.") if children.size > 0
  children.each do |pid, child|
    Einhorn.log_info("Child #{pid.inspect} was signaled #{(child[:last_signaled_at] - now).abs.to_i}s ago. Sending SIGKILL as it is still active after #{Einhorn::State.signal_timeout}s timeout.", :upgrade)
    begin
      Process.kill("KILL", pid)
    rescue Errno::ESRCH
      Einhorn.log_debug("Attempted to SIGKILL child #{pid.inspect} but the process does not exist.")
    end

    child[:signaled].add("KILL")
    child[:last_signaled_at] = Time.now
  end
end

.louder(log = true) ⇒ Object 



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# File 'lib/einhorn/command.rb', line 618

def self.louder(log = true)
  Einhorn::State.verbosity -= 1 if Einhorn::State.verbosity > 0
  output = "Verbosity set to #{Einhorn::State.verbosity}"
  Einhorn.log_info(output) if log
  output
end

.next_index ⇒ Object 



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# File 'lib/einhorn/command.rb', line 265

def self.next_index
  all_indexes = Set.new(Einhorn::State.children.map { |k, st| st[:index] })
  0.upto(all_indexes.length) do |i|
    return i unless all_indexes.include?(i)
  end
end

.prepare_child_environment(index) ⇒ Object 



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# File 'lib/einhorn/command.rb', line 339

def self.prepare_child_environment(index)
  # This is run from the child
  ENV["EINHORN_MASTER_PID"] = Process.ppid.to_s
  ENV["EINHORN_SOCK_PATH"] = Einhorn::Command::Interface.socket_path
  if Einhorn::State.command_socket_as_fd
    socket = UNIXSocket.open(Einhorn::Command::Interface.socket_path)
    Einhorn::TransientState.socket_handles << socket
    ENV["EINHORN_SOCK_FD"] = socket.fileno.to_s
  end

  ENV["EINHORN_FD_COUNT"] = Einhorn::State.bind_fds.length.to_s
  Einhorn::State.bind_fds.each_with_index { |fd, i| ENV["EINHORN_FD_#{i}"] = fd.to_s }

  ENV["EINHORN_CHILD_INDEX"] = index.to_s
end

.prepare_child_process ⇒ Object 



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# File 'lib/einhorn/command.rb', line 385

def self.prepare_child_process
  Process.setpgrp
  Einhorn.renice_self
end

.quieter(log = true) ⇒ Object 



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# File 'lib/einhorn/command.rb', line 611

def self.quieter(log = true)
  Einhorn::State.verbosity += 1 if Einhorn::State.verbosity < 2
  output = "Verbosity set to #{Einhorn::State.verbosity}"
  Einhorn.log_info(output) if log
  output
end

.reap ⇒ Object 



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# File 'lib/einhorn/command.rb', line 9

def self.reap
  loop do
    Einhorn.log_debug("Going to reap a child process")
    pid = Process.wait(-1, Process::WNOHANG)
    return unless pid
    cleanup(pid)
    Einhorn::Event.break_loop
  end
rescue Errno::ECHILD
end

.register_ack(pid) ⇒ Object 



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# File 'lib/einhorn/command.rb', line 83

def self.register_ack(pid)
  unless (spec = Einhorn::State.children[pid])
    Einhorn.log_error("Could not find state for PID #{pid.inspect}; ignoring ACK.")
    return
  end

  if spec[:acked]
    Einhorn.log_error("Pid #{pid.inspect} already ACKed; ignoring new ACK.")
    return
  end

  extra = if Einhorn::State.consecutive_deaths_before_ack > 0
    ", breaking the streak of #{Einhorn::State.consecutive_deaths_before_ack} consecutive unacked workers dying"
  end
  Einhorn::State.consecutive_deaths_before_ack = 0

  spec[:acked] = true
  Einhorn.log_info("Up to #{Einhorn::WorkerPool.ack_count} / #{Einhorn::WorkerPool.ack_target} #{Einhorn::State.ack_mode[:type]} ACKs#{extra}")
  # Could call cull here directly instead, I believe.
  Einhorn::Event.break_loop
end

.register_manual_ack(pid) ⇒ Object 



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# File 'lib/einhorn/command.rb', line 56

def self.register_manual_ack(pid)
  ack_mode = Einhorn::State.ack_mode
  unless ack_mode[:type] == :manual
    Einhorn.log_error("Received a manual ACK for #{pid.inspect}, but ack_mode is #{ack_mode.inspect}. Ignoring ACK.")
    return
  end
  Einhorn.log_info("Received a manual ACK from #{pid.inspect}")
  register_ack(pid)
end

.register_ping(pid, request_id) ⇒ Object 



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# File 'lib/einhorn/command.rb', line 46

def self.register_ping(pid, request_id)
  unless (spec = Einhorn::State.children[pid])
    Einhorn.log_error("Could not find state for PID #{pid.inspect}; ignoring ACK.")
    return
  end

  spec[:pinged_at] = Time.now
  spec[:pinged_request_id] = request_id
end

.register_timer_ack(time, pid) ⇒ Object 



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# File 'lib/einhorn/command.rb', line 66

def self.register_timer_ack(time, pid)
  ack_mode = Einhorn::State.ack_mode
  unless ack_mode[:type] == :timer
    Einhorn.log_error("Received a timer ACK for #{pid.inspect}, but ack_mode is #{ack_mode.inspect}. Ignoring ACK.")
    return
  end

  unless Einhorn::State.children[pid]
    # TODO: Maybe cancel pending ACK timers upon death?
    Einhorn.log_debug("Worker #{pid.inspect} died before its timer ACK happened.")
    return
  end

  Einhorn.log_info("Worker #{pid.inspect} has been up for #{time}s, so we are considering it alive.")
  register_ack(pid)
end

.reload ⇒ Object 



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# File 'lib/einhorn/command.rb', line 213

def self.reload
  unless Einhorn::State.respawn
    Einhorn.log_info("Not reloading einhorn because we're exiting")
    return
  end

  Einhorn.log_info("Reloading einhorn master (#{Einhorn::TransientState.script_name})...", :reload)

  # In case there's anything lurking
  $stdout.flush

  # Spawn a child to pass the state through the pipe
  read, write = Einhorn::Compat.pipe

  fork do
    Einhorn::TransientState.whatami = :state_passer
    Einhorn::State.children[Process.pid] = {type: :state_passer}
    Einhorn::State.generation += 1
    read.close

    begin
      write.write(YAML.dump(dumpable_state))
    rescue Errno::EPIPE => e
      e.message << " (state worker could not write state, which likely means the parent process has died)"
      raise e
    end
    write.close

    exit(0)
  end
  write.close

  unless Einhorn.can_safely_reload?
    Einhorn.log_error("Can not initiate einhorn master reload safely, aborting", :reload)
    Einhorn::State.reloading_for_upgrade = false
    read.close
    return
  end

  begin
    Einhorn.initialize_reload_environment
    respawn_commandline = Einhorn.upgrade_commandline(["--with-state-fd", read.fileno.to_s])
    respawn_commandline << {close_others: false}
    Einhorn.log_info("About to re-exec einhorn master as #{respawn_commandline.inspect}", :reload)
    Einhorn::Compat.exec(*respawn_commandline)
  rescue SystemCallError => e
    Einhorn.log_error("Could not reload! Attempting to continue. Error was: #{e}", :reload)
    Einhorn::State.reloading_for_upgrade = false
    read.close
  end
end

.reload_for_upgrade ⇒ Object 



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# File 'lib/einhorn/command.rb', line 431

def self.reload_for_upgrade
  Einhorn::State.reloading_for_upgrade = true
  reload
end

.replenish ⇒ Object 



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# File 'lib/einhorn/command.rb', line 535

def self.replenish
  return unless Einhorn::State.respawn

  if !Einhorn::State.last_spinup
    replenish_immediately
  else
    replenish_gradually
  end
end

.replenish_gradually(max_unacked = nil) ⇒ Object 



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# File 'lib/einhorn/command.rb', line 561

def self.replenish_gradually(max_unacked = nil)
  return if Einhorn::TransientState.has_outstanding_spinup_timer
  return unless Einhorn::WorkerPool.missing_worker_count > 0

  max_unacked ||= Einhorn::State.config[:max_unacked]

  # default to spinning up at most NCPU workers at once
  unless max_unacked
    begin
      @processor_count ||= Einhorn::Compat.processor_count
    rescue => err
      Einhorn.log_error(err.inspect)
      @processor_count = 1
    end
    max_unacked = @processor_count
  end

  if max_unacked <= 0
    raise ArgumentError.new("max_unacked must be positive")
  end

  # Exponentially backoff automated spinup if we're just having
  # things die before ACKing
  spinup_interval = Einhorn::State.config[:seconds] * (1.5**Einhorn::State.consecutive_deaths_before_ack)
  spinup_interval = [spinup_interval, MAX_SPINUP_INTERVAL].min
  seconds_ago = (Time.now - Einhorn::State.last_spinup).to_f

  if seconds_ago > spinup_interval
    if trigger_spinup?(max_unacked)
      msg = "Last spinup was #{seconds_ago}s ago, and spinup_interval is #{spinup_interval}s, so spinning up a new process."

      if Einhorn::State.consecutive_deaths_before_ack > 0
        Einhorn.log_info("#{msg} (there have been #{Einhorn::State.consecutive_deaths_before_ack} consecutive unacked worker deaths)", :upgrade)
      else
        Einhorn.log_debug(msg)
      end

      spinup
    end
  else
    Einhorn.log_debug("Last spinup was #{seconds_ago}s ago, and spinup_interval is #{spinup_interval}s, so not spinning up a new process.")
  end

  Einhorn::TransientState.has_outstanding_spinup_timer = true
  Einhorn::Event::Timer.open(spinup_interval) do
    Einhorn::TransientState.has_outstanding_spinup_timer = false
    replenish
  end
end

.replenish_immediately ⇒ Object 



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# File 'lib/einhorn/command.rb', line 545

def self.replenish_immediately
  missing = Einhorn::WorkerPool.missing_worker_count
  if missing <= 0
    Einhorn.log_error("Missing is currently #{missing.inspect}, but should always be > 0 when replenish_immediately is called. This probably indicates a bug in Einhorn.")
    return
  end
  Einhorn.log_info("Launching #{missing} new workers")
  missing.times { spinup }
end

.reseed_random ⇒ Object

Reseed common ruby random number generators.

OpenSSL::Random uses the PID to reseed after fork, which means that if a long-lived master process over its lifetime spawns two workers with the same PID, those workers will start with the same OpenSSL seed.

Ruby >= 1.9 has a guard against this in SecureRandom, but any direct users of OpenSSL::Random will still be affected.

Ruby 1.8 didn't even reseed the default random number generator used by Kernel#rand in certain releases.

https://bugs.ruby-lang.org/issues/4579



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# File 'lib/einhorn/command.rb', line 369

def self.reseed_random
  # reseed Kernel#rand
  srand

  # reseed OpenSSL::Random if it's loaded
  if defined?(OpenSSL::Random)
    seed = if defined?(Random)
      Random.new_seed
    else
      # Ruby 1.8
      rand
    end
    OpenSSL::Random.seed(seed.to_s)
  end
end

.set_workers(new) ⇒ Object 



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# File 'lib/einhorn/command.rb', line 183

def self.set_workers(new)
  if new == Einhorn::State.config[:number]
    return ""
  end

  Einhorn::Event.break_loop
  old = Einhorn::State.config[:number]
  Einhorn::State.config[:number] = new
  output = "Altering worker count, #{old} -> #{new}. Will "
  output << if old < new
    "spin up additional workers."
  else
    "gracefully terminate workers."
  end
  warn(output)
  output
end

.setup_parent_watch(expected_ppid) ⇒ Object 



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# File 'lib/einhorn/command.rb', line 390

def self.setup_parent_watch(expected_ppid)
  if Einhorn::State.kill_children_on_exit
    begin
      # NB: Having the USR2 signal handler set to terminate (the default) at
      # this point is required. If it's set to a ruby handler, there are
      # race conditions that could cause the worker to leak.

      Einhorn::Prctl.set_pdeathsig("USR2")
      if Process.ppid != expected_ppid
        Einhorn.log_error("Parent process died before we set pdeathsig; cowardly refusing to exec child process.")
        exit(1)
      end
    rescue NotImplementedError
      # Unsupported OS; silently continue.
    end
  end
end

.signal_all(signal, children = nil, record = true) ⇒ Object 



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# File 'lib/einhorn/command.rb', line 105

def self.signal_all(signal, children = nil, record = true)
  children ||= Einhorn::WorkerPool.workers
  signaled = {}

  Einhorn.log_info("Sending #{signal} to #{children.inspect}", :upgrade)

  children.each do |child|
    unless (spec = Einhorn::State.children[child])
      Einhorn.log_error("Trying to send #{signal} to dead child #{child.inspect}. The fact we tried this probably indicates a bug in Einhorn.", :upgrade)
      next
    end

    if record
      if spec[:signaled].include?(signal)
        Einhorn.log_error("Re-sending #{signal} to already-signaled child #{child.inspect}. It may be slow to spin down, or it may be swallowing #{signal}s.", :upgrade)
      end
      spec[:signaled].add(signal)
      spec[:last_signaled_at] = Time.now
    end

    begin
      Process.kill(signal, child)
    rescue Errno::ESRCH
      Einhorn.log_debug("Attempted to #{signal} child #{child.inspect} but the process does not exist", :upgrade)
    else
      signaled[child] = spec
    end
  end

  if Einhorn::State.signal_timeout && record
    Einhorn::Event::Timer.open(Einhorn::State.signal_timeout) do
      children.each do |child|
        spec = Einhorn::State.children[child]
        next unless spec # Process is already dead and removed by cleanup
        signaled_spec = signaled[child]
        next unless signaled_spec # We got ESRCH when trying to signal
        if spec[:spinup_time] != signaled_spec[:spinup_time]
          Einhorn.log_info("Different spinup time recorded for #{child} after #{Einhorn::State.signal_timeout}s. This probably indicates a PID rollover.", :upgrade)
          next
        end

        Einhorn.log_info("Child #{child.inspect} is still active after #{Einhorn::State.signal_timeout}s. Sending SIGKILL.")
        begin
          Process.kill("KILL", child)
        rescue Errno::ESRCH
        end
        spec[:signaled].add("KILL")
      end
    end

    Einhorn.log_info("Successfully sent #{signal}s to #{signaled.length} processes: #{signaled.keys}")
  end
end

.spinup(cmd = nil) ⇒ Object 



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# File 'lib/einhorn/command.rb', line 272

def self.spinup(cmd = nil)
  cmd ||= Einhorn::State.cmd
  index = next_index
  expected_ppid = Process.pid
  pid = if Einhorn::State.preloaded
    fork do
      Einhorn::TransientState.whatami = :worker
      prepare_child_process

      Einhorn.log_info("About to tear down Einhorn state and run einhorn_main")
      Einhorn::Command::Interface.uninit
      Einhorn::Event.close_all_for_worker
      Einhorn.set_argv(cmd, true)

      reseed_random

      setup_parent_watch(expected_ppid)

      prepare_child_environment(index)
      einhorn_main
    end
  else
    fork do
      Einhorn::TransientState.whatami = :worker
      prepare_child_process

      Einhorn.log_info("About to exec #{cmd.inspect}")
      Einhorn::Command::Interface.uninit
      # Here's the only case where cloexec would help. Since we
      # have to track and manually close FDs for other cases, we
      # may as well just reuse close_all rather than also set
      # cloexec on everything.
      #
      # Note that Ruby 1.9's close_others option is useful here.
      Einhorn::Event.close_all_for_worker

      setup_parent_watch(expected_ppid)

      prepare_child_environment(index)
      Einhorn::Compat.exec(cmd[0], cmd[1..-1], close_others: false)
    end
  end

  Einhorn.log_info("===> Launched #{pid} (index: #{index})", :upgrade)
  Einhorn::State.last_spinup = Time.now
  Einhorn::State.children[pid] = {
    type: :worker,
    version: Einhorn::State.version,
    acked: false,
    signaled: Set.new,
    last_signaled_at: nil,
    index: index,
    spinup_time: Einhorn::State.last_spinup
  }

  # Set up whatever's needed for ACKing
  ack_mode = Einhorn::State.ack_mode
  case type = ack_mode[:type]
  when :timer
    Einhorn::Event::ACKTimer.open(ack_mode[:timeout], pid)
  when :manual
    # nothing to do
  else
    Einhorn.log_error("Unrecognized ACK mode #{type.inspect}")
  end
end

.stop_respawning ⇒ Object 



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# File 'lib/einhorn/command.rb', line 530

def self.stop_respawning
  Einhorn::State.respawn = false
  Einhorn::Event.break_loop
end

.trigger_spinup?(max_unacked) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/einhorn/command.rb', line 625

def self.trigger_spinup?(max_unacked)
  unacked = Einhorn::WorkerPool.unacked_unsignaled_modern_workers.length
  if unacked >= max_unacked
    Einhorn.log_info("There are #{unacked} unacked new workers, and max_unacked is #{max_unacked}, so not spinning up a new process.")
    return false
  elsif Einhorn::State.config[:max_upgrade_additional]
    capacity_exceeded = (Einhorn::State.config[:number] + Einhorn::State.config[:max_upgrade_additional]) - Einhorn::WorkerPool.workers_with_state.length
    if capacity_exceeded < 0
      Einhorn.log_info("Over worker capacity by #{capacity_exceeded.abs} during upgrade, #{Einhorn::WorkerPool.modern_workers.length} new workers of #{Einhorn::WorkerPool.workers_with_state.length} total. Waiting for old workers to exit before spinning up a process.")

      return false
    end
  end

  true
end

.upgrade_workers ⇒ Object 



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# File 'lib/einhorn/command.rb', line 436

def self.upgrade_workers
  if Einhorn::State.upgrading
    Einhorn.log_info("Currently upgrading (#{Einhorn::WorkerPool.ack_count} / #{Einhorn::WorkerPool.ack_target} ACKs; bumping version and starting over)...", :upgrade)
  else
    Einhorn::State.upgrading = true
    u_type = Einhorn::State.smooth_upgrade ? "smooth" : "fleet"
    Einhorn.log_info("Starting #{u_type} upgrade from version" \
                     " #{Einhorn::State.version}...", :upgrade)
  end

  # Reset this, since we've just upgraded to a new universe (I'm
  # not positive this is the right behavior, but it's not
  # obviously wrong.)
  Einhorn::State.consecutive_deaths_before_ack = 0
  Einhorn::State.last_upgraded = Time.now

  Einhorn::State.version += 1
  if Einhorn::State.smooth_upgrade
    replenish_gradually
  else
    replenish_immediately
  end
end