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($$.to_s)
256 @ready_pipe = @ready_pipe.close rescue nil
262 # avoid murdering workers after our master process (or the
263 # machine) comes out of suspend/hibernation
264 if (last_check + @timeout) >= (last_check = Time.now)
265 sleep_time = murder_lazy_workers
267 # wait for workers to wakeup on suspend
268 sleep_time = @timeout/2.0 + 1
270 maintain_worker_count if respawn
271 master_sleep(sleep_time)
272 when :QUIT # graceful shutdown
274 when :TERM, :INT # immediate shutdown
277 when :USR1 # rotate logs
278 logger.info "master reopening logs..."
279 Unicorn::Util.reopen_logs
280 logger.info "master done reopening logs"
281 kill_each_worker(:USR1)
282 when :USR2 # exec binary, stay alive in case something went wrong
285 if Process.ppid == 1 || Process.getpgrp != $$
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 logger.error "Unhandled master loop exception #{e.inspect}."
309 logger.error e.backtrace.join("\n")
311 stop # gracefully shutdown all workers on our way out
312 logger.info "master complete"
313 unlink_pid_safe(pid) if pid
316 # Terminates all workers, but does not exit master process
317 def stop(graceful = true)
319 limit = Time.now + timeout
320 until WORKERS.empty? || Time.now > limit
321 kill_each_worker(graceful ? :QUIT : :TERM)
325 kill_each_worker(:KILL)
329 Unicorn::HttpRequest.input_class.method_defined?(:rewind)
332 def rewindable_input=(bool)
333 Unicorn::HttpRequest.input_class = bool ?
334 Unicorn::TeeInput : Unicorn::StreamInput
337 def client_body_buffer_size
338 Unicorn::TeeInput.client_body_buffer_size
341 def client_body_buffer_size=(bytes)
342 Unicorn::TeeInput.client_body_buffer_size = bytes
345 def trust_x_forwarded
346 Unicorn::HttpParser.trust_x_forwarded?
349 def trust_x_forwarded=(bool)
350 Unicorn::HttpParser.trust_x_forwarded = bool
355 # wait for a signal hander to wake us up and then consume the pipe
356 def master_sleep(sec)
357 IO.select([ SELF_PIPE[0] ], nil, nil, sec) or return
358 SELF_PIPE[0].kgio_tryread(11)
362 SELF_PIPE[1].kgio_trywrite('.') # wakeup master process from select
365 # reaps all unreaped workers
368 wpid, status = Process.waitpid2(-1, Process::WNOHANG)
370 if reexec_pid == wpid
371 logger.error "reaped #{status.inspect} exec()-ed"
373 self.pid = pid.chomp('.oldbin') if pid
376 worker = WORKERS.delete(wpid) and worker.close rescue nil
377 m = "reaped #{status.inspect} worker=#{worker.nr rescue 'unknown'}"
378 status.success? ? logger.info(m) : logger.error(m)
385 # reexecutes the START_CTX with a new binary
389 Process.kill(0, reexec_pid)
390 logger.error "reexec-ed child already running PID:#{reexec_pid}"
398 old_pid = "#{pid}.oldbin"
400 self.pid = old_pid # clear the path for a new pid file
402 logger.error "old PID:#{valid_pid?(old_pid)} running with " \
403 "existing pid=#{old_pid}, refusing rexec"
406 logger.error "error writing pid=#{old_pid} #{e.class} #{e.message}"
411 self.reexec_pid = fork do
412 listener_fds = LISTENERS.map { |sock| sock.fileno }
413 ENV['UNICORN_FD'] = listener_fds.join(',')
414 Dir.chdir(START_CTX[:cwd])
415 cmd = [ START_CTX[0] ].concat(START_CTX[:argv])
417 # avoid leaking FDs we don't know about, but let before_exec
418 # unset FD_CLOEXEC, if anything else in the app eventually
419 # relies on FD inheritence.
420 (3..1024).each do |io|
421 next if listener_fds.include?(io)
422 io = IO.for_fd(io) rescue next
424 io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
426 logger.info "executing #{cmd.inspect} (in #{Dir.pwd})"
427 before_exec.call(self)
430 proc_name 'master (old)'
433 # forcibly terminate all workers that haven't checked in in timeout seconds. The timeout is implemented using an unlinked File
434 def murder_lazy_workers
438 WORKERS.dup.each_pair do |wpid, worker|
440 0 == tick and next # skip workers that are sleeping
444 next_sleep < tmp and next_sleep = tmp
447 logger.error "worker=#{worker.nr} PID:#{wpid} timeout " \
448 "(#{diff}s > #{t}s), killing"
449 kill_worker(:KILL, wpid) # take no prisoners for timeout violations
454 def after_fork_internal
455 @ready_pipe.close if @ready_pipe
456 Unicorn::Configurator::RACKUP.clear
457 @ready_pipe = @init_listeners = @config = @before_exec = @before_fork = nil
459 srand # http://redmine.ruby-lang.org/issues/4338
461 # The OpenSSL PRNG is seeded with only the pid, and apps with frequently
462 # dying workers can recycle pids
463 OpenSSL::Random.seed(rand.to_s) if defined?(OpenSSL::Random)
466 def spawn_missing_workers
468 until (worker_nr += 1) == @worker_processes
469 WORKERS.values.include?(worker_nr) and next
470 worker = Worker.new(worker_nr)
471 before_fork.call(self, worker)
473 WORKERS[pid] = worker
481 @logger.error(e) rescue nil
485 def maintain_worker_count
486 (off = WORKERS.size - worker_processes) == 0 and return
487 off < 0 and return spawn_missing_workers
488 WORKERS.dup.each_pair { |wpid,w|
489 w.nr >= worker_processes and kill_worker(:QUIT, wpid) rescue nil
493 # if we get any error, try to write something back to the client
494 # assuming we haven't closed the socket, but don't get hung up
495 # if the socket is already closed or broken. We'll always ensure
496 # the socket is closed at the end of this function
497 def handle_error(client, e)
499 when EOFError,Errno::ECONNRESET,Errno::EPIPE,Errno::EINVAL,Errno::EBADF
500 Unicorn::Const::ERROR_500_RESPONSE
501 when Unicorn::RequestURITooLongError
502 Unicorn::Const::ERROR_414_RESPONSE
503 when Unicorn::RequestEntityTooLargeError
504 Unicorn::Const::ERROR_413_RESPONSE
505 when Unicorn::HttpParserError # try to tell the client they're bad
506 Unicorn::Const::ERROR_400_RESPONSE
508 logger.error "app error: #{e.inspect}"
509 logger.error e.backtrace.join("\n")
510 Unicorn::Const::ERROR_500_RESPONSE
512 client.kgio_trywrite(msg)
517 # once a client is accepted, it is processed in its entirety here
518 # in 3 easy steps: read request, call app, write app response
519 def process_client(client)
520 status, headers, body = @app.call(env = @request.read(client))
522 if 100 == status.to_i
523 client.write(Unicorn::Const::EXPECT_100_RESPONSE)
524 env.delete(Unicorn::Const::HTTP_EXPECT)
525 status, headers, body = @app.call(env)
527 @request.headers? or headers = nil
528 http_response_write(client, status, headers, body)
529 client.close # flush and uncork socket immediately, no keepalive
531 handle_error(client, e)
534 # gets rid of stuff the worker has no business keeping track of
535 # to free some resources and drops all sig handlers.
536 # traps for USR1, USR2, and HUP may be set in the after_fork Proc
538 def init_worker_process(worker)
539 QUEUE_SIGS.each { |sig| trap(sig, nil) }
540 trap(:CHLD, 'DEFAULT')
542 proc_name "worker[#{worker.nr}]"
546 LISTENERS.each { |sock| sock.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }
547 after_fork.call(self, worker) # can drop perms
548 worker.user(*user) if user.kind_of?(Array) && ! worker.switched
549 self.timeout /= 2.0 # halve it for select()
550 build_app! unless preload_app
553 def reopen_worker_logs(worker_nr)
554 logger.info "worker=#{worker_nr} reopening logs..."
555 Unicorn::Util.reopen_logs
556 logger.info "worker=#{worker_nr} done reopening logs"
559 logger.error(e) rescue nil
560 exit!(77) # EX_NOPERM in sysexits.h
563 # runs inside each forked worker, this sits around and waits
564 # for connections and doesn't die until the parent dies (or is
565 # given a INT, QUIT, or TERM signal)
566 def worker_loop(worker)
568 init_worker_process(worker)
569 nr = 0 # this becomes negative if we need to reopen logs
570 ready = LISTENERS.dup
572 # closing anything we IO.select on will raise EBADF
573 trap(:USR1) { nr = -65536; SELF_PIPE[0].close rescue nil }
574 trap(:QUIT) { worker = nil; LISTENERS.each { |s| s.close rescue nil }.clear }
575 [:TERM, :INT].each { |sig| trap(sig) { exit!(0) } } # instant shutdown
576 logger.info "worker=#{worker.nr} ready"
580 nr < 0 and reopen_worker_logs(worker.nr)
583 while sock = ready.shift
584 if client = sock.kgio_tryaccept
585 worker.tick = Time.now.to_i
586 process_client(client)
593 # make the following bet: if we accepted clients this round,
594 # we're probably reasonably busy, so avoid calling select()
595 # and do a speculative non-blocking accept() on ready listeners
596 # before we sleep again in select().
597 unless nr == 0 # (nr < 0) => reopen logs (unlikely)
598 ready = LISTENERS.dup
602 ppid == Process.ppid or return
604 # timeout used so we can detect parent death:
605 ret = IO.select(LISTENERS, nil, SELF_PIPE, timeout) and ready = ret[0]
610 logger.error "Unhandled listen loop exception #{e.inspect}."
611 logger.error e.backtrace.join("\n")
616 # delivers a signal to a worker and fails gracefully if the worker
617 # is no longer running.
618 def kill_worker(signal, wpid)
619 Process.kill(signal, wpid)
621 worker = WORKERS.delete(wpid) and worker.close rescue nil
624 # delivers a signal to each worker
625 def kill_each_worker(signal)
626 WORKERS.keys.each { |wpid| kill_worker(signal, wpid) }
629 # unlinks a PID file at given +path+ if it contains the current PID
630 # still potentially racy without locking the directory (which is
631 # non-portable and may interact badly with other programs), but the
632 # window for hitting the race condition is small
633 def unlink_pid_safe(path)
634 (File.read(path).to_i == $$ and File.unlink(path)) rescue nil
637 # returns a PID if a given path contains a non-stale PID file,
640 wpid = File.read(path).to_i
642 Process.kill(0, wpid)
644 rescue Errno::ESRCH, Errno::ENOENT
645 # don't unlink stale pid files, racy without non-portable locking...
650 logger.info "reloading config_file=#{config.config_file}"
651 config[:listeners].replace(@init_listeners)
654 kill_each_worker(:QUIT)
655 Unicorn::Util.reopen_logs
657 build_app! if preload_app
658 logger.info "done reloading config_file=#{config.config_file}"
659 rescue StandardError, LoadError, SyntaxError => e
660 logger.error "error reloading config_file=#{config.config_file}: " \
661 "#{e.class} #{e.message} #{e.backtrace}"
662 self.app = loaded_app
665 # returns an array of string names for the given listener array
666 def listener_names(listeners = LISTENERS)
667 listeners.map { |io| sock_name(io) }
671 if app.respond_to?(:arity) && app.arity == 0
672 if defined?(Gem) && Gem.respond_to?(:refresh)
673 logger.info "Refreshing Gem list"
681 $0 = ([ File.basename(START_CTX[0]), tag
682 ]).concat(START_CTX[:argv]).join(' ')
685 def redirect_io(io, path)
686 File.open(path, 'ab') { |fp| io.reopen(fp) } if path
691 SELF_PIPE.each { |io| io.close rescue nil }
692 SELF_PIPE.replace(Kgio::Pipe.new)
693 SELF_PIPE.each { |io| io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }
696 def inherit_listeners!
697 # inherit sockets from parents, they need to be plain Socket objects
698 # before they become Kgio::UNIXServer or Kgio::TCPServer
699 inherited = ENV['UNICORN_FD'].to_s.split(/,/).map do |fd|
700 io = Socket.for_fd(fd.to_i)
701 set_server_sockopt(io, listener_opts[sock_name(io)])
703 logger.info "inherited addr=#{sock_name(io)} fd=#{fd}"
707 config_listeners = config[:listeners].dup
708 LISTENERS.replace(inherited)
710 # we start out with generic Socket objects that get cast to either
711 # Kgio::TCPServer or Kgio::UNIXServer objects; but since the Socket
712 # objects share the same OS-level file descriptor as the higher-level
713 # *Server objects; we need to prevent Socket objects from being
715 config_listeners -= listener_names
716 if config_listeners.empty? && LISTENERS.empty?
717 config_listeners << Unicorn::Const::DEFAULT_LISTEN
718 @init_listeners << Unicorn::Const::DEFAULT_LISTEN
719 START_CTX[:argv] << "-l#{Unicorn::Const::DEFAULT_LISTEN}"
721 config_listeners.each { |addr| listen(addr) }
722 raise ArgumentError, "no listeners" if LISTENERS.empty?