1 # -*- encoding: binary -*-
3 # This is the process manager of Unicorn. This manages worker
4 # processes which in turn handle the I/O and application process.
5 # Listener sockets are started in the master process and shared with
6 # forked worker children.
8 # Users do not need to know the internals of this class, but reading the
9 # {source}[http://bogomips.org/unicorn.git/tree/lib/unicorn/http_server.rb]
10 # is education for programmers wishing to learn how \Unicorn works.
11 # See Unicorn::Configurator for information on how to configure \Unicorn.
12 class Unicorn::HttpServer
14 attr_accessor :app, :request, :timeout, :worker_processes,
15 :before_fork, :after_fork, :before_exec,
16 :listener_opts, :preload_app,
17 :reexec_pid, :orig_app, :init_listeners,
18 :master_pid, :config, :ready_pipe, :user
19 attr_reader :pid, :logger
20 include Unicorn::SocketHelper
21 include Unicorn::HttpResponse
23 # backwards compatibility with 1.x
24 Worker = Unicorn::Worker
26 # all bound listener sockets
29 # This hash maps PIDs to Workers
32 # We use SELF_PIPE differently in the master and worker processes:
34 # * The master process never closes or reinitializes this once
35 # initialized. Signal handlers in the master process will write to
36 # it to wake up the master from IO.select in exactly the same manner
37 # djb describes in http://cr.yp.to/docs/selfpipe.html
39 # * The workers immediately close the pipe they inherit from the
40 # master and replace it with a new pipe after forking. This new
41 # pipe is also used to wakeup from IO.select from inside (worker)
42 # signal handlers. However, workers *close* the pipe descriptors in
43 # the signal handlers to raise EBADF in IO.select instead of writing
44 # like we do in the master. We cannot easily use the reader set for
45 # IO.select because LISTENERS is already that set, and it's extra
46 # work (and cycles) to distinguish the pipe FD from the reader set
47 # once IO.select returns. So we're lazy and just close the pipe when
48 # a (rare) signal arrives in the worker and reinitialize the pipe later.
51 # signal queue used for self-piping
54 # list of signals we care about and trap in master.
55 QUEUE_SIGS = [ :WINCH, :QUIT, :INT, :TERM, :USR1, :USR2, :HUP, :TTIN, :TTOU ]
58 # We populate this at startup so we can figure out how to reexecute
59 # and upgrade the currently running instance of Unicorn
60 # This Hash is considered a stable interface and changing its contents
61 # will allow you to switch between different installations of Unicorn
62 # or even different installations of the same applications without
63 # downtime. Keys of this constant Hash are described as follows:
65 # * 0 - the path to the unicorn/unicorn_rails executable
66 # * :argv - a deep copy of the ARGV array the executable originally saw
67 # * :cwd - the working directory of the application, this is where
68 # you originally started Unicorn.
70 # To change your unicorn executable to a different path without downtime,
71 # you can set the following in your Unicorn config file, HUP and then
72 # continue with the traditional USR2 + QUIT upgrade steps:
74 # Unicorn::HttpServer::START_CTX[0] = "/home/bofh/1.9.2/bin/unicorn"
76 :argv => ARGV.map { |arg| arg.dup },
79 # We favor ENV['PWD'] since it is (usually) symlink aware for Capistrano
81 START_CTX[:cwd] = begin
82 a = File.stat(pwd = ENV['PWD'])
83 b = File.stat(Dir.pwd)
84 a.ino == b.ino && a.dev == b.dev ? pwd : Dir.pwd
90 # Creates a working server on host:port (strange things happen if
91 # port isn't a Number). Use HttpServer::run to start the server and
92 # HttpServer.run.join to join the thread that's processing
93 # incoming requests on the socket.
94 def initialize(app, options = {})
96 @request = Unicorn::HttpRequest.new
99 @ready_pipe = options.delete(:ready_pipe)
100 @init_listeners = options[:listeners] ? options[:listeners].dup : []
101 options[:use_defaults] = true
102 self.config = Unicorn::Configurator.new(options)
103 self.listener_opts = {}
105 # we try inheriting listeners first, so we bind them later.
106 # we don't write the pid file until we've bound listeners in case
107 # unicorn was started twice by mistake. Even though our #pid= method
108 # checks for stale/existing pid files, race conditions are still
109 # possible (and difficult/non-portable to avoid) and can be likely
110 # to clobber the pid if the second start was in quick succession
111 # after the first, so we rely on the listener binding to fail in
112 # that case. Some tests (in and outside of this source tree) and
113 # monitoring tools may also rely on pid files existing before we
114 # attempt to connect to the listener(s)
115 config.commit!(self, :skip => [:listeners, :pid])
119 # Runs the thing. Returns self so you can run join on it
122 # this pipe is used to wake us up from select(2) in #join when signals
123 # are trapped. See trap_deferred.
126 # setup signal handlers before writing pid file in case people get
127 # trigger happy and send signals as soon as the pid file exists.
128 # Note that signals don't actually get handled until the #join method
129 QUEUE_SIGS.each { |sig| trap(sig) { SIG_QUEUE << sig; awaken_master } }
130 trap(:CHLD) { awaken_master }
131 self.pid = config[:pid]
134 build_app! if preload_app
135 spawn_missing_workers
139 # replaces current listener set with +listeners+. This will
140 # close the socket if it will not exist in the new listener set
141 def listeners=(listeners)
142 cur_names, dead_names = [], []
143 listener_names.each do |name|
145 # mark unlinked sockets as dead so we can rebind them
146 (File.socket?(name) ? cur_names : dead_names) << name
151 set_names = listener_names(listeners)
152 dead_names.concat(cur_names - set_names).uniq!
154 LISTENERS.delete_if do |io|
155 if dead_names.include?(sock_name(io))
156 IO_PURGATORY.delete_if do |pio|
157 pio.fileno == io.fileno && (pio.close rescue nil).nil? # true
159 (io.close rescue nil).nil? # true
161 set_server_sockopt(io, listener_opts[sock_name(io)])
166 (set_names - cur_names).each { |addr| listen(addr) }
169 def stdout_path=(path); redirect_io($stdout, path); end
170 def stderr_path=(path); redirect_io($stderr, path); end
173 Unicorn::HttpRequest::DEFAULTS["rack.logger"] = @logger = obj
176 # sets the path for the PID file of the master process
179 if x = valid_pid?(path)
180 return path if pid && path == pid && x == $$
181 if x == reexec_pid && pid =~ /\.oldbin\z/
182 logger.warn("will not set pid=#{path} while reexec-ed "\
183 "child is running PID:#{x}")
186 raise ArgumentError, "Already running on PID:#{x} " \
187 "(or pid=#{path} is stale)"
190 unlink_pid_safe(pid) if pid
194 tmp = "#{File.dirname(path)}/#{rand}.#$$"
195 File.open(tmp, File::RDWR|File::CREAT|File::EXCL, 0644)
200 File.rename(fp.path, path)
206 # add a given address to the +listeners+ set, idempotently
207 # Allows workers to add a private, per-process listener via the
208 # after_fork hook. Very useful for debugging and testing.
209 # +:tries+ may be specified as an option for the number of times
210 # to retry, and +:delay+ may be specified as the time in seconds
211 # to delay between retries.
212 # A negative value for +:tries+ indicates the listen will be
213 # retried indefinitely, this is useful when workers belonging to
214 # different masters are spawned during a transparent upgrade.
215 def listen(address, opt = {}.merge(listener_opts[address] || {}))
216 address = config.expand_addr(address)
217 return if String === address && listener_names.include?(address)
219 delay = opt[:delay] || 0.5
220 tries = opt[:tries] || 5
222 io = bind_listen(address, opt)
223 unless Kgio::TCPServer === io || Kgio::UNIXServer === io
227 logger.info "listening on addr=#{sock_name(io)} fd=#{io.fileno}"
230 rescue Errno::EADDRINUSE => err
231 logger.error "adding listener failed addr=#{address} (in use)"
232 raise err if tries == 0
234 logger.error "retrying in #{delay} seconds " \
235 "(#{tries < 0 ? 'infinite' : tries} tries left)"
239 logger.fatal "error adding listener addr=#{address}"
244 # monitors children and receives signals forever
245 # (or until a termination signal is sent). This handles signals
246 # one-at-a-time time and we'll happily drop signals in case somebody
247 # is signalling us too often.
250 last_check = Time.now
253 logger.info "master process ready" # test_exec.rb relies on this message
255 @ready_pipe.syswrite($$.to_s)
256 @ready_pipe = @ready_pipe.close rescue nil
262 # avoid murdering workers after our master process (or the
263 # machine) comes out of suspend/hibernation
264 if (last_check + @timeout) >= (last_check = Time.now)
265 sleep_time = murder_lazy_workers
267 sleep_time = @timeout/2.0 + 1
268 @logger.debug("waiting #{sleep_time}s after suspend/hibernation")
270 maintain_worker_count if respawn
271 master_sleep(sleep_time)
272 when :QUIT # graceful shutdown
274 when :TERM, :INT # immediate shutdown
277 when :USR1 # rotate logs
278 logger.info "master reopening logs..."
279 Unicorn::Util.reopen_logs
280 logger.info "master done reopening logs"
281 kill_each_worker(:USR1)
282 when :USR2 # exec binary, stay alive in case something went wrong
285 if Process.ppid == 1 || Process.getpgrp != $$
287 logger.info "gracefully stopping all workers"
288 kill_each_worker(:QUIT)
289 self.worker_processes = 0
291 logger.info "SIGWINCH ignored because we're not daemonized"
295 self.worker_processes += 1
297 self.worker_processes -= 1 if self.worker_processes > 0
300 if config.config_file
302 else # exec binary and exit if there's no config file
303 logger.info "config_file not present, reexecuting binary"
308 Unicorn.log_error(@logger, "master loop error", e)
310 stop # gracefully shutdown all workers on our way out
311 logger.info "master complete"
312 unlink_pid_safe(pid) if pid
315 # Terminates all workers, but does not exit master process
316 def stop(graceful = true)
318 limit = Time.now + timeout
319 until WORKERS.empty? || Time.now > limit
320 kill_each_worker(graceful ? :QUIT : :TERM)
324 kill_each_worker(:KILL)
328 Unicorn::HttpRequest.input_class.method_defined?(:rewind)
331 def rewindable_input=(bool)
332 Unicorn::HttpRequest.input_class = bool ?
333 Unicorn::TeeInput : Unicorn::StreamInput
336 def client_body_buffer_size
337 Unicorn::TeeInput.client_body_buffer_size
340 def client_body_buffer_size=(bytes)
341 Unicorn::TeeInput.client_body_buffer_size = bytes
344 def trust_x_forwarded
345 Unicorn::HttpParser.trust_x_forwarded?
348 def trust_x_forwarded=(bool)
349 Unicorn::HttpParser.trust_x_forwarded = bool
354 # wait for a signal hander to wake us up and then consume the pipe
355 def master_sleep(sec)
356 IO.select([ SELF_PIPE[0] ], nil, nil, sec) or return
357 SELF_PIPE[0].kgio_tryread(11)
361 SELF_PIPE[1].kgio_trywrite('.') # wakeup master process from select
364 # reaps all unreaped workers
367 wpid, status = Process.waitpid2(-1, Process::WNOHANG)
369 if reexec_pid == wpid
370 logger.error "reaped #{status.inspect} exec()-ed"
372 self.pid = pid.chomp('.oldbin') if pid
375 worker = WORKERS.delete(wpid) and worker.close rescue nil
376 m = "reaped #{status.inspect} worker=#{worker.nr rescue 'unknown'}"
377 status.success? ? logger.info(m) : logger.error(m)
384 # reexecutes the START_CTX with a new binary
388 Process.kill(0, reexec_pid)
389 logger.error "reexec-ed child already running PID:#{reexec_pid}"
397 old_pid = "#{pid}.oldbin"
399 self.pid = old_pid # clear the path for a new pid file
401 logger.error "old PID:#{valid_pid?(old_pid)} running with " \
402 "existing pid=#{old_pid}, refusing rexec"
405 logger.error "error writing pid=#{old_pid} #{e.class} #{e.message}"
410 self.reexec_pid = fork do
411 listener_fds = Hash[LISTENERS.map do |sock|
412 # IO#close_on_exec= will be available on any future version of
413 # Ruby that sets FD_CLOEXEC by default on new file descriptors
414 # ref: http://redmine.ruby-lang.org/issues/5041
415 sock.close_on_exec = false if sock.respond_to?(:close_on_exec=)
416 [ sock.fileno, sock ]
418 ENV['UNICORN_FD'] = listener_fds.keys.join(',')
419 Dir.chdir(START_CTX[:cwd])
420 cmd = [ START_CTX[0] ].concat(START_CTX[:argv])
422 # avoid leaking FDs we don't know about, but let before_exec
423 # unset FD_CLOEXEC, if anything else in the app eventually
424 # relies on FD inheritence.
425 (3..1024).each do |io|
426 next if listener_fds.include?(io)
427 io = IO.for_fd(io) rescue next
429 io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
432 # exec(command, hash) works in at least 1.9.1+, but will only be
433 # required in 1.9.4/2.0.0 at earliest.
434 cmd << listener_fds if RUBY_VERSION >= "1.9.1"
435 logger.info "executing #{cmd.inspect} (in #{Dir.pwd})"
436 before_exec.call(self)
439 proc_name 'master (old)'
442 # forcibly terminate all workers that haven't checked in in timeout seconds. The timeout is implemented using an unlinked File
443 def murder_lazy_workers
444 next_sleep = @timeout - 1
446 WORKERS.dup.each_pair do |wpid, worker|
448 0 == tick and next # skip workers that are sleeping
450 tmp = @timeout - diff
452 next_sleep > tmp and next_sleep = tmp
456 logger.error "worker=#{worker.nr} PID:#{wpid} timeout " \
457 "(#{diff}s > #{@timeout}s), killing"
458 kill_worker(:KILL, wpid) # take no prisoners for timeout violations
460 next_sleep <= 0 ? 1 : next_sleep
463 def after_fork_internal
464 @ready_pipe.close if @ready_pipe
465 Unicorn::Configurator::RACKUP.clear
466 @ready_pipe = @init_listeners = @before_exec = @before_fork = nil
468 srand # http://redmine.ruby-lang.org/issues/4338
470 # The OpenSSL PRNG is seeded with only the pid, and apps with frequently
471 # dying workers can recycle pids
472 OpenSSL::Random.seed(rand.to_s) if defined?(OpenSSL::Random)
475 def spawn_missing_workers
477 until (worker_nr += 1) == @worker_processes
478 WORKERS.value?(worker_nr) and next
479 worker = Worker.new(worker_nr)
480 before_fork.call(self, worker)
482 WORKERS[pid] = worker
490 @logger.error(e) rescue nil
494 def maintain_worker_count
495 (off = WORKERS.size - worker_processes) == 0 and return
496 off < 0 and return spawn_missing_workers
497 WORKERS.dup.each_pair { |wpid,w|
498 w.nr >= worker_processes and kill_worker(:QUIT, wpid) rescue nil
502 # if we get any error, try to write something back to the client
503 # assuming we haven't closed the socket, but don't get hung up
504 # if the socket is already closed or broken. We'll always ensure
505 # the socket is closed at the end of this function
506 def handle_error(client, e)
508 when EOFError,Errno::ECONNRESET,Errno::EPIPE,Errno::EINVAL,Errno::EBADF
509 Unicorn::Const::ERROR_500_RESPONSE
510 when Unicorn::RequestURITooLongError
511 Unicorn::Const::ERROR_414_RESPONSE
512 when Unicorn::RequestEntityTooLargeError
513 Unicorn::Const::ERROR_413_RESPONSE
514 when Unicorn::HttpParserError # try to tell the client they're bad
515 Unicorn::Const::ERROR_400_RESPONSE
517 Unicorn.log_error(@logger, "app error", e)
518 Unicorn::Const::ERROR_500_RESPONSE
520 client.kgio_trywrite(msg)
525 # once a client is accepted, it is processed in its entirety here
526 # in 3 easy steps: read request, call app, write app response
527 def process_client(client)
528 status, headers, body = @app.call(env = @request.read(client))
530 if 100 == status.to_i
531 client.write(Unicorn::Const::EXPECT_100_RESPONSE)
532 env.delete(Unicorn::Const::HTTP_EXPECT)
533 status, headers, body = @app.call(env)
535 @request.headers? or headers = nil
536 http_response_write(client, status, headers, body)
537 client.close # flush and uncork socket immediately, no keepalive
539 handle_error(client, e)
542 EXIT_SIGS = [ :QUIT, :TERM, :INT ]
543 WORKER_QUEUE_SIGS = QUEUE_SIGS - EXIT_SIGS
545 # gets rid of stuff the worker has no business keeping track of
546 # to free some resources and drops all sig handlers.
547 # traps for USR1, USR2, and HUP may be set in the after_fork Proc
549 def init_worker_process(worker)
550 # we'll re-trap :QUIT later for graceful shutdown iff we accept clients
551 EXIT_SIGS.each { |sig| trap(sig) { exit!(0) } }
552 exit!(0) if (SIG_QUEUE & EXIT_SIGS)[0]
553 WORKER_QUEUE_SIGS.each { |sig| trap(sig, nil) }
554 trap(:CHLD, 'DEFAULT')
556 proc_name "worker[#{worker.nr}]"
560 LISTENERS.each { |sock| sock.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }
561 after_fork.call(self, worker) # can drop perms
562 worker.user(*user) if user.kind_of?(Array) && ! worker.switched
563 self.timeout /= 2.0 # halve it for select()
565 build_app! unless preload_app
566 @after_fork = @listener_opts = @orig_app = nil
569 def reopen_worker_logs(worker_nr)
570 logger.info "worker=#{worker_nr} reopening logs..."
571 Unicorn::Util.reopen_logs
572 logger.info "worker=#{worker_nr} done reopening logs"
575 logger.error(e) rescue nil
576 exit!(77) # EX_NOPERM in sysexits.h
579 # runs inside each forked worker, this sits around and waits
580 # for connections and doesn't die until the parent dies (or is
581 # given a INT, QUIT, or TERM signal)
582 def worker_loop(worker)
584 init_worker_process(worker)
585 nr = 0 # this becomes negative if we need to reopen logs
589 # closing anything we IO.select on will raise EBADF
590 trap(:USR1) { nr = -65536; SELF_PIPE[0].close rescue nil }
591 trap(:QUIT) { worker = nil; LISTENERS.each { |s| s.close rescue nil }.clear }
592 logger.info "worker=#{worker.nr} ready"
595 nr < 0 and reopen_worker_logs(worker.nr)
598 worker.tick = Time.now.to_i
599 while sock = ready.shift
600 if client = sock.kgio_tryaccept
601 process_client(client)
603 worker.tick = Time.now.to_i
608 # make the following bet: if we accepted clients this round,
609 # we're probably reasonably busy, so avoid calling select()
610 # and do a speculative non-blocking accept() on ready listeners
611 # before we sleep again in select().
612 unless nr == 0 # (nr < 0) => reopen logs (unlikely)
617 ppid == Process.ppid or return
619 # timeout used so we can detect parent death:
620 worker.tick = Time.now.to_i
621 ret = IO.select(l, nil, SELF_PIPE, @timeout) and ready = ret[0]
625 Unicorn.log_error(@logger, "listen loop error", e) if worker
629 # delivers a signal to a worker and fails gracefully if the worker
630 # is no longer running.
631 def kill_worker(signal, wpid)
632 Process.kill(signal, wpid)
634 worker = WORKERS.delete(wpid) and worker.close rescue nil
637 # delivers a signal to each worker
638 def kill_each_worker(signal)
639 WORKERS.keys.each { |wpid| kill_worker(signal, wpid) }
642 # unlinks a PID file at given +path+ if it contains the current PID
643 # still potentially racy without locking the directory (which is
644 # non-portable and may interact badly with other programs), but the
645 # window for hitting the race condition is small
646 def unlink_pid_safe(path)
647 (File.read(path).to_i == $$ and File.unlink(path)) rescue nil
650 # returns a PID if a given path contains a non-stale PID file,
653 wpid = File.read(path).to_i
655 Process.kill(0, wpid)
657 rescue Errno::ESRCH, Errno::ENOENT
658 # don't unlink stale pid files, racy without non-portable locking...
663 logger.info "reloading config_file=#{config.config_file}"
664 config[:listeners].replace(@init_listeners)
667 kill_each_worker(:QUIT)
668 Unicorn::Util.reopen_logs
670 build_app! if preload_app
671 logger.info "done reloading config_file=#{config.config_file}"
672 rescue StandardError, LoadError, SyntaxError => e
673 Unicorn.log_error(@logger,
674 "error reloading config_file=#{config.config_file}", e)
675 self.app = loaded_app
678 # returns an array of string names for the given listener array
679 def listener_names(listeners = LISTENERS)
680 listeners.map { |io| sock_name(io) }
684 if app.respond_to?(:arity) && app.arity == 0
685 if defined?(Gem) && Gem.respond_to?(:refresh)
686 logger.info "Refreshing Gem list"
694 $0 = ([ File.basename(START_CTX[0]), tag
695 ]).concat(START_CTX[:argv]).join(' ')
698 def redirect_io(io, path)
699 File.open(path, 'ab') { |fp| io.reopen(fp) } if path
704 SELF_PIPE.each { |io| io.close rescue nil }
705 SELF_PIPE.replace(Kgio::Pipe.new)
706 SELF_PIPE.each { |io| io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }
709 def inherit_listeners!
710 # inherit sockets from parents, they need to be plain Socket objects
711 # before they become Kgio::UNIXServer or Kgio::TCPServer
712 inherited = ENV['UNICORN_FD'].to_s.split(/,/).map do |fd|
713 io = Socket.for_fd(fd.to_i)
714 set_server_sockopt(io, listener_opts[sock_name(io)])
716 logger.info "inherited addr=#{sock_name(io)} fd=#{fd}"
720 config_listeners = config[:listeners].dup
721 LISTENERS.replace(inherited)
723 # we start out with generic Socket objects that get cast to either
724 # Kgio::TCPServer or Kgio::UNIXServer objects; but since the Socket
725 # objects share the same OS-level file descriptor as the higher-level
726 # *Server objects; we need to prevent Socket objects from being
728 config_listeners -= listener_names
729 if config_listeners.empty? && LISTENERS.empty?
730 config_listeners << Unicorn::Const::DEFAULT_LISTEN
731 @init_listeners << Unicorn::Const::DEFAULT_LISTEN
732 START_CTX[:argv] << "-l#{Unicorn::Const::DEFAULT_LISTEN}"
734 config_listeners.each { |addr| listen(addr) }
735 raise ArgumentError, "no listeners" if LISTENERS.empty?