Class: Puma::Server

Inherits:
Object
  • Object
show all
Includes:
Const, Response
Defined in:
lib/puma/server.rb

Overview

The HTTP Server itself. Serves out a single Rack app.

This class is used by the ‘Puma::Single` and `Puma::Cluster` classes to generate one or more `Puma::Server` instances capable of handling requests. Each Puma process will contain one `Puma::Server` instance.

The ‘Puma::Server` instance pulls requests from the socket, adds them to a `Puma::Reactor` where they get eventually passed to a `Puma::ThreadPool`.

Each ‘Puma::Server` will have one reactor and one thread pool.

Defined Under Namespace

Modules: FiberPerRequest

Constant Summary collapse

UNPACK_TCP_STATE_FROM_TCP_INFO = 
"C".freeze
STAT_METHODS =

List of methods invoked by #stats.

Version:

  • 5.0.0

[
  :backlog,
  :running,
  :pool_capacity,
  :busy_threads,
  :backlog_max,
  :max_threads,
  :requests_count,
  :reactor_max,
].freeze

Constants included from Response

Response::BODY_LEN_MAX, Response::CUSTOM_STAT, Response::IO_BODY_MAX, Response::IO_BUFFER_LEN_MAX, Response::SOCKET_WRITE_ERR_MSG

Constants included from Const

Const::BANNED_HEADER_KEY, Const::CGI_VER, Const::CHUNKED, Const::CHUNK_SIZE, Const::CLOSE, Const::CLOSE_CHUNKED, Const::CODE_NAME, Const::COLON, Const::CONNECTION_CLOSE, Const::CONNECTION_KEEP_ALIVE, Const::CONTENT_LENGTH, Const::CONTENT_LENGTH2, Const::CONTENT_LENGTH_S, Const::CONTINUE, Const::DQUOTE, Const::EARLY_HINTS, Const::ERROR_RESPONSE, Const::GATEWAY_INTERFACE, Const::HALT_COMMAND, Const::HEAD, Const::HIJACK, Const::HIJACK_IO, Const::HIJACK_P, Const::HTTP, Const::HTTPS, Const::HTTPS_KEY, Const::HTTP_10_200, Const::HTTP_11, Const::HTTP_11_100, Const::HTTP_11_200, Const::HTTP_CONNECTION, Const::HTTP_EXPECT, Const::HTTP_HEADER_DELIMITER, Const::HTTP_HOST, Const::HTTP_VERSION, Const::HTTP_X_FORWARDED_FOR, Const::HTTP_X_FORWARDED_PROTO, Const::HTTP_X_FORWARDED_SCHEME, Const::HTTP_X_FORWARDED_SSL, Const::IANA_HTTP_METHODS, Const::ILLEGAL_HEADER_KEY_REGEX, Const::ILLEGAL_HEADER_VALUE_REGEX, Const::KEEP_ALIVE, Const::LINE_END, Const::LOCALHOST, Const::LOCALHOST_IPV4, Const::LOCALHOST_IPV6, Const::MAX_BODY, Const::MAX_HEADER, Const::NEWLINE, Const::PATH_INFO, Const::PORT_443, Const::PORT_80, Const::PROXY_PROTOCOL_V1_REGEX, Const::PUMA_CONFIG, Const::PUMA_PEERCERT, Const::PUMA_SERVER_STRING, Const::PUMA_SOCKET, Const::PUMA_TMP_BASE, Const::PUMA_VERSION, Const::QUERY_STRING, Const::RACK_AFTER_REPLY, Const::RACK_INPUT, Const::RACK_RESPONSE_FINISHED, Const::RACK_URL_SCHEME, Const::REMOTE_ADDR, Const::REQUEST_METHOD, Const::REQUEST_PATH, Const::REQUEST_URI, Const::RESTART_COMMAND, Const::SERVER_NAME, Const::SERVER_PORT, Const::SERVER_PROTOCOL, Const::SERVER_SOFTWARE, Const::STOP_COMMAND, Const::SUPPORTED_HTTP_METHODS, Const::TRANSFER_ENCODING, Const::TRANSFER_ENCODING2, Const::TRANSFER_ENCODING_CHUNKED, Const::UNMASKABLE_HEADERS, Const::UNSPECIFIED_IPV4, Const::UNSPECIFIED_IPV6, Const::WRITE_TIMEOUT

Class Attribute Summary collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Response

#handle_request, #illegal_header_key?, #illegal_header_value?, #prepare_response

Constructor Details

#initialize(app, events = nil, options = {}) ⇒ Server

Note:

Several instance variables exist so they are available for testing, and have default values set via fetch. Normally the values are set via ‘::Puma::Configuration.puma_default_options`.

Note:

The ‘events` parameter is set to nil, and set to `Events.new` in code. Often `options` needs to be passed, but `events` does not. Using nil allows calling code to not require events.rb.

Create a server for the rack app app.

log_writer is a Puma::LogWriter object used to log info and error messages.

events is a Puma::Events object used to notify application status events.

Server#run returns a thread that you can join on to wait for the server to do its work.



76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
 
# File 'lib/puma/server.rb', line 76

def initialize(app, events = nil, options = {})
  @app = app
  @events = events || Events.new

  @check, @notify = nil
  @status = :stop

  @thread = nil
  @thread_pool = nil
  @reactor = nil

  @env_set_http_version = nil

  @options = if options.is_a?(UserFileDefaultOptions)
    options
  else
    UserFileDefaultOptions.new(options, Configuration::DEFAULTS)
  end

  @clustered                 = (@options.fetch :workers, 0) > 0
  @worker_write              = @options[:worker_write]
  @log_writer                = @options.fetch :log_writer, LogWriter.stdio
  @early_hints               = @options[:early_hints]
  @first_data_timeout        = @options[:first_data_timeout]
  @persistent_timeout        = @options[:persistent_timeout]
  @idle_timeout              = @options[:idle_timeout]
  @min_threads               = @options[:min_threads]
  @max_threads               = @options[:max_threads]
  @queue_requests            = @options[:queue_requests]
  @max_keep_alive            = @options[:max_keep_alive]
  @enable_keep_alives        = @options[:enable_keep_alives]
  @enable_keep_alives      &&= @queue_requests
  @io_selector_backend       = @options[:io_selector_backend]
  @http_content_length_limit = @options[:http_content_length_limit]
  @cluster_accept_loop_delay = ClusterAcceptLoopDelay.new(
    workers: @options[:workers],
    max_delay: @options[:wait_for_less_busy_worker] || 0 # Real default is in Configuration::DEFAULTS, this is for unit testing
  )

  if @options[:fiber_per_request]
    singleton_class.prepend(FiberPerRequest)
  end

  # make this a hash, since we prefer `key?` over `include?`
  @supported_http_methods =
    if @options[:supported_http_methods] == :any
      :any
    else
      if (ary = @options[:supported_http_methods])
        ary
      else
        SUPPORTED_HTTP_METHODS
      end.sort.product([nil]).to_h.freeze
    end

  temp = !!(@options[:environment] =~ /\A(development|test)\z/)
  @leak_stack_on_error = @options[:environment] ? temp : true

  @binder = Binder.new(log_writer, @options)

  ENV['RACK_ENV'] ||= "development"

  @mode = :http

  @precheck_closing = true

  @requests_count = 0

  @idle_timeout_reached = false
end

Class Attribute Details

.current ⇒ Object (readonly) 



153
154
155
 
# File 'lib/puma/server.rb', line 153

def current
  Thread.current.puma_server
end

Instance Attribute Details

#app ⇒ Object

Returns the value of attribute app.



56
57
58
 
# File 'lib/puma/server.rb', line 56

def app
  @app
end

#auto_trim_time ⇒ Object (readonly)

TODO:

the following may be deprecated in the future



52
53
54
 
# File 'lib/puma/server.rb', line 52

def auto_trim_time
  @auto_trim_time
end

#backlog ⇒ Object (readonly) 



228
229
230
 
# File 'lib/puma/server.rb', line 228

def backlog
  @thread_pool&.backlog
end

#binder ⇒ Object

Returns the value of attribute binder.



57
58
59
 
# File 'lib/puma/server.rb', line 57

def binder
  @binder
end

#connected_ports ⇒ Object (readonly) 



769
770
771
 
# File 'lib/puma/server.rb', line 769

def connected_ports
  @binder.connected_ports
end

#early_hints ⇒ Object (readonly)

TODO:

the following may be deprecated in the future



52
53
54
 
# File 'lib/puma/server.rb', line 52

def early_hints
  @early_hints
end

#events ⇒ Object (readonly)

Returns the value of attribute events.



47
48
49
 
# File 'lib/puma/server.rb', line 47

def events
  @events
end

#first_data_timeout ⇒ Object (readonly)

TODO:

the following may be deprecated in the future



52
53
54
 
# File 'lib/puma/server.rb', line 52

def first_data_timeout
  @first_data_timeout
end

#leak_stack_on_error ⇒ Object (readonly)

TODO:

the following may be deprecated in the future



52
53
54
 
# File 'lib/puma/server.rb', line 52

def leak_stack_on_error
  @leak_stack_on_error
end

#log_writer ⇒ Object (readonly)

Returns the value of attribute log_writer.



46
47
48
 
# File 'lib/puma/server.rb', line 46

def log_writer
  @log_writer
end

#max_threads ⇒ Object (readonly)

for #stats



48
49
50
 
# File 'lib/puma/server.rb', line 48

def max_threads
  @max_threads
end

#min_threads ⇒ Object (readonly)

for #stats



48
49
50
 
# File 'lib/puma/server.rb', line 48

def min_threads
  @min_threads
end

#options ⇒ Object (readonly)

Returns the value of attribute options.



44
45
46
 
# File 'lib/puma/server.rb', line 44

def options
  @options
end

#persistent_timeout ⇒ Object (readonly)

TODO:

the following may be deprecated in the future



52
53
54
 
# File 'lib/puma/server.rb', line 52

def persistent_timeout
  @persistent_timeout
end

#pool_capacity ⇒ Object (readonly)

This number represents the number of requests that the server is capable of taking right now.

For example if the number is 5 then it means there are 5 threads sitting idle ready to take a request. If one request comes in, then the value would be 4 until it finishes processing.



245
246
247
 
# File 'lib/puma/server.rb', line 245

def pool_capacity
  @thread_pool&.pool_capacity
end

#reaping_time ⇒ Object (readonly)

TODO:

the following may be deprecated in the future



52
53
54
 
# File 'lib/puma/server.rb', line 52

def reaping_time
  @reaping_time
end

#requests_count ⇒ Object (readonly)

Version:

  • 5.0.0



49
50
51
 
# File 'lib/puma/server.rb', line 49

def requests_count
  @requests_count
end

#running ⇒ Object (readonly) 



233
234
235
 
# File 'lib/puma/server.rb', line 233

def running
  @thread_pool&.spawned
end

#stats ⇒ Hash (readonly)

Returns a hash of stats about the running server for reporting purposes.

Returns:

  • (Hash) —

    hash containing stat info from ‘Server` and `ThreadPool`

Version:

  • 5.0.0



694
695
696
697
698
699
700
701
 
# File 'lib/puma/server.rb', line 694

def stats
  stats = @thread_pool&.stats || {}
  stats[:max_threads]    = @max_threads
  stats[:requests_count] = @requests_count
  stats[:reactor_max] = @reactor.reactor_max if @reactor
  reset_max
  stats
end

#thread ⇒ Object (readonly)

Returns the value of attribute thread.



45
46
47
 
# File 'lib/puma/server.rb', line 45

def thread
  @thread
end

Class Method Details

.closed_socket_supported? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean)

Version:

  • 5.0.0



165
166
167
 
# File 'lib/puma/server.rb', line 165

def closed_socket_supported?
  Socket.const_defined?(:TCP_INFO) && Socket.const_defined?(:IPPROTO_TCP)
end

.tcp_cork_supported? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean)

Version:

  • 5.0.0



159
160
161
 
# File 'lib/puma/server.rb', line 159

def tcp_cork_supported?
  Socket.const_defined?(:TCP_CORK) && Socket.const_defined?(:IPPROTO_TCP)
end

Instance Method Details

#add_ssl_listener(host, port, ctx, optimize_for_latency = true, backlog = 1024) ⇒ Object 



716
717
718
719
 
# File 'lib/puma/server.rb', line 716

def add_ssl_listener(host, port, ctx, optimize_for_latency = true,
                     backlog = 1024)
  @binder.add_ssl_listener host, port, ctx, optimize_for_latency, backlog
end

#add_tcp_listener(host, port, optimize_for_latency = true, backlog = 1024) ⇒ Object 



712
713
714
 
# File 'lib/puma/server.rb', line 712

def add_tcp_listener(host, port, optimize_for_latency = true, backlog = 1024)
  @binder.add_tcp_listener host, port, optimize_for_latency, backlog
end

#add_unix_listener(path, umask = nil, mode = nil, backlog = 1024) ⇒ Object 



721
722
723
 
# File 'lib/puma/server.rb', line 721

def add_unix_listener(path, umask = nil, mode = nil, backlog = 1024)
  @binder.add_unix_listener path, umask, mode, backlog
end

#begin_restart(sync = false) ⇒ Object 



668
669
670
671
 
# File 'lib/puma/server.rb', line 668

def begin_restart(sync=false)
  notify_safely(RESTART_COMMAND)
  @thread.join if @thread && sync
end

#client_error(e, client, requests = 1) ⇒ Object

Handle various error types thrown by Client I/O operations.



576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
 
# File 'lib/puma/server.rb', line 576

def client_error(e, client, requests = 1)
  # Swallow, do not log
  return if [ConnectionError, EOFError].include?(e.class)

  case e
  when MiniSSL::SSLError
    lowlevel_error(e, client.env)
    @log_writer.ssl_error e, client.io
  when HttpParserError
    response_to_error(client, requests, e, client.error_status_code || 400)
    @log_writer.parse_error e, client
  when HttpParserError501
    response_to_error(client, requests, e, 501)
    @log_writer.parse_error e, client
  else
    response_to_error(client, requests, e, 500)
    @log_writer.unknown_error e, nil, "Read"
  end
end

#close_client_safely(client) ⇒ Object

:nodoc:



555
556
557
558
559
560
561
562
563
 
# File 'lib/puma/server.rb', line 555

def close_client_safely(client)
  client.close
rescue IOError, SystemCallError
  # Already closed
rescue MiniSSL::SSLError => e
  @log_writer.ssl_error e, client.io
rescue StandardError => e
  @log_writer.unknown_error e, nil, "Client"
end

#closed_socket?(socket) ⇒ Boolean

Returns:

  • (Boolean) 


206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
 
# File 'lib/puma/server.rb', line 206

def closed_socket?(socket)
  skt = socket.to_io
  return false unless skt.kind_of?(TCPSocket) && @precheck_closing

  begin
    tcp_info = skt.getsockopt(Socket::IPPROTO_TCP, Socket::TCP_INFO)
  rescue IOError, SystemCallError
    @precheck_closing = false
    false
  else
    state = tcp_info.unpack(UNPACK_TCP_STATE_FROM_TCP_INFO)[0]
    # TIME_WAIT: 6, CLOSE: 7, CLOSE_WAIT: 8, LAST_ACK: 9, CLOSING: 11
    (state >= 6 && state <= 9) || state == 11
  end
end

#cork_socket(socket) ⇒ Object

6 == Socket::IPPROTO_TCP 3 == TCP_CORK 1/0 == turn on/off



180
181
182
183
184
185
186
 
# File 'lib/puma/server.rb', line 180

def cork_socket(socket)
  skt = socket.to_io
  begin
    skt.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_CORK, 1) if skt.kind_of? TCPSocket
  rescue IOError, SystemCallError
  end
end

#graceful_shutdown ⇒ Object

Wait for all outstanding requests to finish.



633
634
635
636
637
638
639
 
# File 'lib/puma/server.rb', line 633

def graceful_shutdown
  if @status != :restart
    @binder.close
  end

  @thread_pool.shutdown(options[:force_shutdown_after])
end

#halt(sync = false) ⇒ Object 



663
664
665
666
 
# File 'lib/puma/server.rb', line 663

def halt(sync=false)
  notify_safely(HALT_COMMAND)
  @thread.join if @thread && sync
end

#handle_check ⇒ Object

:nodoc:



457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
 
# File 'lib/puma/server.rb', line 457

def handle_check
  cmd = @check.read(1)

  case cmd
  when STOP_COMMAND
    @status = :stop
    return true
  when HALT_COMMAND
    @status = :halt
    return true
  when RESTART_COMMAND
    @status = :restart
    return true
  end

  false
end

#handle_servers ⇒ Object 



337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
 
# File 'lib/puma/server.rb', line 337

def handle_servers
  @env_set_http_version = Object.const_defined?(:Rack) && ::Rack.respond_to?(:release) &&
    Gem::Version.new(::Rack.release) < Gem::Version.new('3.1.0')

  begin
    check = @check
    sockets = [check] + @binder.ios
    pool = @thread_pool
    queue_requests = @queue_requests
    drain = options[:drain_on_shutdown] ? 0 : nil

    addr_send_name, addr_value = case options[:remote_address]
    when :value
      [:peerip=, options[:remote_address_value]]
    when :header
      [:remote_addr_header=, options[:remote_address_header]]
    when :proxy_protocol
      [:expect_proxy_proto=, options[:remote_address_proxy_protocol]]
    else
      [nil, nil]
    end

    while @status == :run || (drain && shutting_down?)
      begin
        ios = IO.select sockets, nil, nil, (shutting_down? ? 0 : @idle_timeout)
        unless ios
          unless shutting_down?
            @idle_timeout_reached = true

            if @clustered
              @worker_write << "#{PipeRequest::PIPE_IDLE}#{Process.pid}\n" rescue nil
              next
            else
              @log_writer.log "- Idle timeout reached"
              @status = :stop
            end
          end

          break
        end

        if @idle_timeout_reached && @clustered
          @idle_timeout_reached = false
          @worker_write << "#{PipeRequest::PIPE_IDLE}#{Process.pid}\n" rescue nil
        end

        ios.first.each do |sock|
          if sock == check
            break if handle_check
          else
            # if ThreadPool out_of_band code is running, we don't want to add
            # clients until the code is finished.
            pool.wait_while_out_of_band_running

            # A well rested herd (cluster) runs faster
            if @cluster_accept_loop_delay.on? && (busy_threads_plus_todo = pool.busy_threads) > 0
              delay = @cluster_accept_loop_delay.calculate(
                max_threads: @max_threads,
                busy_threads_plus_todo: busy_threads_plus_todo
              )
              sleep(delay)
            end

            io = begin
              sock.accept_nonblock
            rescue IO::WaitReadable
              next
            end
            drain += 1 if shutting_down?

            client = new_client(io, sock)
            client.send(addr_send_name, addr_value) if addr_value
            pool << client
          end
        end
      rescue IOError, Errno::EBADF
        # In the case that any of the sockets are unexpectedly close.
        raise
      rescue StandardError => e
        @log_writer.unknown_error e, nil, "Listen loop"
      end
    end

    @log_writer.debug { "Drained #{drain} additional connections." } if drain
    @events.fire :state, @status

    if queue_requests
      @queue_requests = false
      @reactor.shutdown
    end

    graceful_shutdown if @status == :stop || @status == :restart
  rescue Exception => e
    @log_writer.unknown_error e, nil, "Exception handling servers"
  ensure
    # Errno::EBADF is infrequently raised
    [@check, @notify].each do |io|
      begin
        io.close unless io.closed?
      rescue Errno::EBADF
      end
    end
    @notify = nil
    @check = nil
  end

  @events.fire :state, :done
end

#inherit_binder(bind) ⇒ Object 



147
148
149
 
# File 'lib/puma/server.rb', line 147

def inherit_binder(bind)
  @binder = bind
end

#lowlevel_error(e, env, status = 500) ⇒ Object

A fallback rack response if @app raises as exception.



598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
 
# File 'lib/puma/server.rb', line 598

def lowlevel_error(e, env, status=500)
  if handler = options[:lowlevel_error_handler]
    if handler.arity == 1
      return handler.call(e)
    elsif handler.arity == 2
      return handler.call(e, env)
    else
      return handler.call(e, env, status)
    end
  end

  if @leak_stack_on_error
    backtrace = e.backtrace.nil? ? '<no backtrace available>' : e.backtrace.join("\n")
    [status, {}, ["Puma caught this error: #{e.message} (#{e.class})\n#{backtrace}"]]
  else
    [status, {}, [""]]
  end
end

#new_client(io, sock) ⇒ Object

:nodoc:



447
448
449
450
451
452
453
454
 
# File 'lib/puma/server.rb', line 447

def new_client(io, sock)
  client = Client.new(io, @binder.env(sock))
  client.listener = sock
  client.env_set_http_version = @env_set_http_version
  client.http_content_length_limit = @http_content_length_limit
  client.supported_http_methods = @supported_http_methods
  client
end

#process_client(processor, client) ⇒ Object

Given a connection on client, handle the incoming requests, or queue the connection in the Reactor if no request is available.

This method is called from a ThreadPool processor thread.

This method supports HTTP Keep-Alive so it may, depending on if the client indicates that it supports keep alive, wait for another request before returning.

Return true if one or more requests were processed.



485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
 
# File 'lib/puma/server.rb', line 485

def process_client(processor, client)
  close_socket = true

  requests = 0

  begin
    if @queue_requests && !client.eagerly_finish

      client.set_timeout(@first_data_timeout)
      if @reactor.add client
        close_socket = false
        return false
      end
    end

    with_force_shutdown(client) do
      client.finish(@first_data_timeout)
    end

    can_loop = true
    while can_loop
      can_loop = false
      @requests_count += 1
      case handle_request(processor, client, requests + 1)
      when :close
      when :async
        close_socket = false
      when :keep_alive
        requests += 1

        client.reset

        # This indicates data exists in the client read buffer and there may be
        # additional requests on it, so process them
        next_request_ready = if client.has_back_to_back_requests?
          with_force_shutdown(client) { client.process_back_to_back_requests }
        else
          with_force_shutdown(client) { client.eagerly_finish }
        end

        if next_request_ready
          # When Puma has spare threads, allow this one to be monopolized
          # Perf optimization for https://github.com/puma/puma/issues/3788
          if @thread_pool.waiting > 0
            can_loop = true
          else
            @thread_pool << client
            close_socket = false
          end
        elsif @queue_requests
          client.set_timeout @persistent_timeout
          if @reactor.add client
            close_socket = false
          end
        end
      end
    end
    true
  rescue StandardError => e
    client_error(e, client, requests)
    # The ensure tries to close +client+ down
    requests > 0
  ensure
    client.io_buffer.reset

    close_client_safely(client) if close_socket
  end
end

#reactor_wakeup(client) ⇒ Object

This method is called from the Reactor thread when a queued Client receives data, times out, or when the Reactor is shutting down.

While the code lives in the Server, the logic is executed on the reactor thread, independently from the server.

It is responsible for ensuring that a request has been completely received before it starts to be processed by the ThreadPool. This may be known as read buffering. If read buffering is not done, and no other read buffering is performed (such as by an application server such as nginx) then the application would be subject to a slow client attack.

For a graphical representation of how the request buffer works see [architecture.md](github.com/puma/puma/blob/main/docs/architecture.md).

The method checks to see if it has the full header and body with the ‘Puma::Client#try_to_finish` method. If the full request has been sent, then the request is passed to the ThreadPool (`@thread_pool << client`) so that a “processor thread” can pick up the request and begin to execute application logic. The Client is then removed from the reactor (return `true`).

If a client object times out, a 408 response is written, its connection is closed, and the object is removed from the reactor (return ‘true`).

If the Reactor is shutting down, all Clients are either timed out or passed to the ThreadPool, depending on their current state (#can_close?).

Otherwise, if the full request is not ready then the client will remain in the reactor (return ‘false`). When the client sends more data to the socket the `Puma::Client` object will wake up and again be checked to see if it’s ready to be passed to the thread pool.



321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
 
# File 'lib/puma/server.rb', line 321

def reactor_wakeup(client)
  shutdown = !@queue_requests
  if client.try_to_finish || (shutdown && !client.can_close?)
    @thread_pool << client
  elsif shutdown || client.timeout == 0
    client.timeout!
  else
    client.set_timeout(@first_data_timeout)
    false
  end
rescue StandardError => e
  client_error(e, client)
  close_client_safely(client)
  true
end

#reset_max ⇒ Object 



703
704
705
706
 
# File 'lib/puma/server.rb', line 703

def reset_max
  @reactor.reactor_max = 0 if @reactor
  @thread_pool&.reset_max
end

#run(background = true, thread_name: 'srv') ⇒ Object

Runs the server.

If background is true (the default) then a thread is spun up in the background to handle requests. Otherwise requests are handled synchronously.



255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
 
# File 'lib/puma/server.rb', line 255

def run(background=true, thread_name: 'srv')
  BasicSocket.do_not_reverse_lookup = true

  @events.fire :state, :booting

  @status = :run

  @thread_pool = ThreadPool.new(thread_name, options, server: self) do |processor, client|
    process_client(processor, client)
  end

  if @queue_requests
    @reactor = Reactor.new(@io_selector_backend) { |c|
      # Inversion of control, the reactor is calling a method on the server when it
      # is done buffering a request or receives a new request from a keepalive connection.
      self.reactor_wakeup(c)
    }
    @reactor.run
  end

  @thread_pool.auto_reap! if options[:reaping_time]
  @thread_pool.auto_trim! if @min_threads != @max_threads && options[:auto_trim_time]

  @check, @notify = Puma::Util.pipe unless @notify

  @events.fire :state, :running

  if background
    @thread = Thread.new do
      Puma.set_thread_name thread_name
      handle_servers
    end
    return @thread
  else
    handle_servers
  end
end

#shutting_down? ⇒ Boolean

Returns:

  • (Boolean) 


673
674
675
 
# File 'lib/puma/server.rb', line 673

def shutting_down?
  @status == :stop || @status == :restart
end

#stop(sync = false) ⇒ Object

Stops the acceptor thread and then causes the processor threads to finish off the request queue before finally exiting.



658
659
660
661
 
# File 'lib/puma/server.rb', line 658

def stop(sync=false)
  notify_safely(STOP_COMMAND)
  @thread.join if @thread && sync
end

#uncork_socket(socket) ⇒ Object 



188
189
190
191
192
193
194
 
# File 'lib/puma/server.rb', line 188

def uncork_socket(socket)
  skt = socket.to_io
  begin
    skt.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_CORK, 0) if skt.kind_of? TCPSocket
  rescue IOError, SystemCallError
  end
end

#update_thread_pool_min_max(min: @min_threads, max: @max_threads) ⇒ void

Note:

If validation fails, a warning message is logged and no changes are made.

This method returns an undefined value.

Updates the minimum and maximum number of threads in the thread pool.

This method allows dynamic adjustment of the thread pool size while the server is running. It validates the provided values and updates both the thread pool and the server’s thread configuration.

Examples:

Update both min and max threads

server.update_thread_pool_min_max(min: 2, max: 8)

Update only the minimum threads

server.update_thread_pool_min_max(min: 4)

Update only the maximum threads

server.update_thread_pool_min_max(max: 16)

Parameters:

  • min (Integer) (defaults to: @min_threads) —

    The minimum number of threads to maintain in the pool. Defaults to the current minimum if not specified. Must be greater than 0 and less than or equal to max.

  • max (Integer) (defaults to: @max_threads) —

    The maximum number of threads allowed in the pool. Defaults to the current maximum if not specified. Must be greater than or equal to min.



751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
 
# File 'lib/puma/server.rb', line 751

def update_thread_pool_min_max(min: @min_threads, max: @max_threads)
  if min > max
    @log_writer.log "`min' value cannot be greater than `max' value."
    return
  end

  if min < 0
    @log_writer.log "`min' value cannot be less than 0"
    return
  end

  @thread_pool&.with_mutex do
    @thread_pool.min, @thread_pool.max = min, max
    @min_threads, @max_threads = min, max
  end
end

#with_force_shutdown(client, &block) ⇒ Object

Triggers a client timeout if the thread-pool shuts down during execution of the provided block.



567
568
569
570
571
 
# File 'lib/puma/server.rb', line 567

def with_force_shutdown(client, &block)
  @thread_pool.with_force_shutdown(&block)
rescue ThreadPool::ForceShutdown
  client.timeout!
end