Class: Puma::Cluster

Inherits:
Runner show all
Defined in:
lib/puma/cluster.rb

Defined Under Namespace

Classes: Worker

Instance Method Summary collapse

Methods inherited from Runner

#app, #before_restart, #daemon?, #development?, #error, #load_and_bind, #log, #output_header, #redirect_io, #start_control, #start_server

Constructor Details

#initialize(cli) ⇒ Cluster

Returns a new instance of Cluster.



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# File 'lib/puma/cluster.rb', line 5

def initialize(cli)
  super cli

  @phase = 0
  @workers = []

  @phased_state = :idle
  @phased_restart = false
end

Instance Method Details

#all_workers_booted? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/puma/cluster.rb', line 74

def all_workers_booted?
  @workers.count { |w| !w.booted? } == 0
end

#check_workers ⇒ Object 



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# File 'lib/puma/cluster.rb', line 78

def check_workers
  while @workers.any?
    pid = Process.waitpid(-1, Process::WNOHANG)
    break unless pid

    @workers.delete_if { |w| w.pid == pid }
  end

  spawn_workers

  if @phased_state == :idle && all_workers_booted?
    # If we're running at proper capacity, check to see if
    # we need to phase any workers out (which will restart
    # in the right phase).
    #
    w = @workers.find { |x| x.phase != @phase }

    if w
      @phased_state = :waiting
      log "- Stopping #{w.pid} for phased upgrade..."
      w.term
    end
  end
end

#halt ⇒ Object 



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# File 'lib/puma/cluster.rb', line 182

def halt
  @status = :halt
  wakeup!
end

#phased_restart ⇒ Object 



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# File 'lib/puma/cluster.rb', line 161

def phased_restart
  return false if @options[:preload_app]

  @phased_restart = true
  wakeup!

  true
end

#preload? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/puma/cluster.rb', line 191

def preload?
  @options[:preload_app]
end

#restart ⇒ Object 



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# File 'lib/puma/cluster.rb', line 156

def restart
  @restart = true
  stop
end

#run ⇒ Object 



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# File 'lib/puma/cluster.rb', line 195

def run
  @status = :run

  output_header "cluster"

  log "* Process workers: #{@options[:workers]}"

  if preload?
    log "* Preloading application"
    load_and_bind
  else
    log "* Phased restart available"

    unless @cli.config.app_configured?
      error "No application configured, nothing to run"
      exit 1
    end

    @cli.binder.parse @options[:binds], self
  end

  read, @wakeup = Puma::Util.pipe

  Signal.trap "SIGCHLD" do
    wakeup!
  end

  master_pid = Process.pid

  Signal.trap "SIGTERM" do
    # The worker installs their own SIGTERM when booted.
    # Until then, this is run by the worker and the worker
    # should just exit if they get it.
    if Process.pid != master_pid
      log "Early termination of worker"
      exit! 0
    else
      stop
    end
  end

  # Used by the workers to detect if the master process dies.
  # If select says that @check_pipe is ready, it's because the
  # master has exited and @suicide_pipe has been automatically
  # closed.
  #
  @check_pipe, @suicide_pipe = Puma::Util.pipe

  if daemon?
    log "* Daemonizing..."
    Process.daemon(true)
  else
    log "Use Ctrl-C to stop"
  end

  redirect_io

  start_control

  @cli.write_state

  @master_read, @worker_write = read, @wakeup
  spawn_workers

  Signal.trap "SIGINT" do
    stop
  end

  @cli.events.fire_on_booted!

  begin
    while @status == :run
      begin
        res = IO.select([read], nil, nil, 5)

        if res
          req = read.read_nonblock(1)

          if req == "b"
            pid = read.gets.to_i
            w = @workers.find { |x| x.pid == pid }
            if w
              w.boot!
              log "- Worker #{pid} booted, phase: #{w.phase}"
            else
              log "! Out-of-sync worker list, no #{pid} worker"
            end
          end
        end

        if @phased_restart
          start_phased_restart
          @phased_restart = false
        end

        check_workers

      rescue Interrupt
        @status = :stop
      end
    end

    stop_workers unless @status == :halt
  ensure
    @check_pipe.close
    @suicide_pipe.close
    read.close
    @wakeup.close
  end
end

#spawn_workers ⇒ Object 



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# File 'lib/puma/cluster.rb', line 56

def spawn_workers
  diff = @options[:workers] - @workers.size

  upgrade = (@phased_state == :waiting)

  master = Process.pid

  diff.times do
    pid = fork { worker(upgrade, master) }
    @cli.debug "Spawned worker: #{pid}"
    @workers << Worker.new(pid, @phase)
  end

  if diff > 0
    @phased_state = :idle
  end
end

#start_phased_restart ⇒ Object 



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# File 'lib/puma/cluster.rb', line 26

def start_phased_restart
  @phase += 1
  log "- Starting phased worker restart, phase: #{@phase}"
end

#stats ⇒ Object 



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# File 'lib/puma/cluster.rb', line 187

def stats
  %Q!{ "workers": #{@workers.size}, "phase": #{@phase} }!
end

#stop ⇒ Object 



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# File 'lib/puma/cluster.rb', line 170

def stop
  @status = :stop
  wakeup!
end

#stop_blocked ⇒ Object 



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# File 'lib/puma/cluster.rb', line 175

def stop_blocked
  @status = :stop if @status == :run
  wakeup!
  @control.stop(true) if @control
  Process.waitall
end

#stop_workers ⇒ Object 



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# File 'lib/puma/cluster.rb', line 15

def stop_workers
  log "- Gracefully shutting down workers..."
  @workers.each { |x| x.term }

  begin
    Process.waitall
  rescue Interrupt
    log "! Cancelled waiting for workers"
  end
end

#wakeup! ⇒ Object 



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# File 'lib/puma/cluster.rb', line 103

def wakeup!
  begin
    @wakeup.write "!" unless @wakeup.closed?
  rescue SystemCallError, IOError
  end
end

#worker(upgrade, master) ⇒ Object 



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# File 'lib/puma/cluster.rb', line 110

def worker(upgrade, master)
  $0 = "puma: cluster worker: #{master}"
  Signal.trap "SIGINT", "IGNORE"

  @master_read.close
  @suicide_pipe.close

  Thread.new do
    IO.select [@check_pipe]
    log "! Detected parent died, dying"
    exit! 1
  end

  # Be sure to change the directory again before loading
  # the app. This way we can pick up new code.
  if upgrade
    if dir = @options[:worker_directory]
      log "+ Changing to #{dir}"
      Dir.chdir dir
    end
  end

  # Invoke any worker boot hooks so they can get
  # things in shape before booting the app.
  hooks = @options[:worker_boot]
  hooks.each { |h| h.call }

  server = start_server

  Signal.trap "SIGTERM" do
    server.stop
  end

  begin
    @worker_write << "b#{Process.pid}\n"
  rescue SystemCallError, IOError
    STDERR.puts "Master seems to have exitted, exitting."
    return
  end

  server.run.join

ensure
  @worker_write.close
end