1 # -*- encoding: binary -*-
4 require 'unicorn/socket_helper'
7 # Unicorn module containing all of the classes (include C extensions) for running
8 # a Unicorn web server. It contains a minimalist HTTP server with just enough
9 # functionality to service web application requests fast as possible.
11 autoload :Const, 'unicorn/const'
12 autoload :HttpRequest, 'unicorn/http_request'
13 autoload :HttpResponse, 'unicorn/http_response'
14 autoload :Configurator, 'unicorn/configurator'
15 autoload :TeeInput, 'unicorn/tee_input'
16 autoload :Util, 'unicorn/util'
19 def run(app, options = {})
20 HttpServer.new(app, options).start.join
24 # This is the process manager of Unicorn. This manages worker
25 # processes which in turn handle the I/O and application process.
26 # Listener sockets are started in the master process and shared with
27 # forked worker children.
29 class HttpServer < Struct.new(:listener_opts, :timeout, :worker_processes,
30 :before_fork, :after_fork, :before_exec,
31 :logger, :pid, :app, :preload_app,
32 :reexec_pid, :orig_app, :init_listeners,
34 include ::Unicorn::SocketHelper
36 # prevents IO objects in here from being GC-ed
39 # all bound listener sockets
42 # This hash maps PIDs to Workers
45 # See: http://cr.yp.to/docs/selfpipe.html
48 # signal queue used for self-piping
51 # constant lookups are faster and we're single-threaded/non-reentrant
52 REQUEST = HttpRequest.new
54 # We populate this at startup so we can figure out how to reexecute
55 # and upgrade the currently running instance of Unicorn
57 :argv => ARGV.map { |arg| arg.dup },
58 # don't rely on Dir.pwd here since it's not symlink-aware, and
59 # symlink dirs are the default with Capistrano...
60 :cwd => `/bin/sh -c pwd`.chomp("\n"),
64 class Worker < Struct.new(:nr, :tmp)
65 # worker objects may be compared to just plain numbers
71 # Creates a working server on host:port (strange things happen if
72 # port isn't a Number). Use HttpServer::run to start the server and
73 # HttpServer.run.join to join the thread that's processing
74 # incoming requests on the socket.
75 def initialize(app, options = {})
78 self.init_listeners = options[:listeners] ? options[:listeners].dup : []
79 self.config = Configurator.new(options.merge(:use_defaults => true))
80 self.listener_opts = {}
81 config.commit!(self, :skip => [:listeners, :pid])
85 # Runs the thing. Returns self so you can run join on it
87 BasicSocket.do_not_reverse_lookup = true
89 # inherit sockets from parents, they need to be plain Socket objects
90 # before they become UNIXServer or TCPServer
91 inherited = ENV['UNICORN_FD'].to_s.split(/,/).map do |fd|
92 io = Socket.for_fd(fd.to_i)
93 set_server_sockopt(io, listener_opts[sock_name(io)])
95 logger.info "inherited addr=#{sock_name(io)} fd=#{fd}"
99 config_listeners = config[:listeners].dup
100 LISTENERS.replace(inherited)
102 # we start out with generic Socket objects that get cast to either
103 # TCPServer or UNIXServer objects; but since the Socket objects
104 # share the same OS-level file descriptor as the higher-level *Server
105 # objects; we need to prevent Socket objects from being garbage-collected
106 config_listeners -= listener_names
107 if config_listeners.empty? && LISTENERS.empty?
108 config_listeners << Unicorn::Const::DEFAULT_LISTEN
109 init_listeners << Unicorn::Const::DEFAULT_LISTEN
110 START_CTX[:argv] << "-l#{Unicorn::Const::DEFAULT_LISTEN}"
112 config_listeners.each { |addr| listen(addr) }
113 raise ArgumentError, "no listeners" if LISTENERS.empty?
114 self.pid = config[:pid]
116 build_app! if preload_app
117 maintain_worker_count
121 # replaces current listener set with +listeners+. This will
122 # close the socket if it will not exist in the new listener set
123 def listeners=(listeners)
124 cur_names, dead_names = [], []
125 listener_names.each do |name|
127 # mark unlinked sockets as dead so we can rebind them
128 (File.socket?(name) ? cur_names : dead_names) << name
133 set_names = listener_names(listeners)
134 dead_names.concat(cur_names - set_names).uniq!
136 LISTENERS.delete_if do |io|
137 if dead_names.include?(sock_name(io))
138 IO_PURGATORY.delete_if do |pio|
139 pio.fileno == io.fileno && (pio.close rescue nil).nil? # true
141 (io.close rescue nil).nil? # true
143 set_server_sockopt(io, listener_opts[sock_name(io)])
148 (set_names - cur_names).each { |addr| listen(addr) }
151 def stdout_path=(path); redirect_io($stdout, path); end
152 def stderr_path=(path); redirect_io($stderr, path); end
154 alias_method :set_pid, :pid=
157 # sets the path for the PID file of the master process
160 if x = valid_pid?(path)
161 return path if pid && path == pid && x == $$
162 raise ArgumentError, "Already running on PID:#{x} " \
163 "(or pid=#{path} is stale)"
166 unlink_pid_safe(pid) if pid
167 File.open(path, 'wb') { |fp| fp.syswrite("#$$\n") } if path
171 # add a given address to the +listeners+ set, idempotently
172 # Allows workers to add a private, per-process listener via the
173 # after_fork hook. Very useful for debugging and testing.
174 # +:tries+ may be specified as an option for the number of times
175 # to retry, and +:delay+ may be specified as the time in seconds
176 # to delay between retries.
177 # A negative value for +:tries+ indicates the listen will be
178 # retried indefinitely, this is useful when workers belonging to
179 # different masters are spawned during a transparent upgrade.
180 def listen(address, opt = {}.merge(listener_opts[address] || {}))
181 address = config.expand_addr(address)
182 return if String === address && listener_names.include?(address)
184 delay = opt[:delay] || 0.5
185 tries = opt[:tries] || 5
187 io = bind_listen(address, opt)
188 unless TCPServer === io || UNIXServer === io
192 logger.info "listening on addr=#{sock_name(io)} fd=#{io.fileno}"
195 rescue Errno::EADDRINUSE => err
196 logger.error "adding listener failed addr=#{address} (in use)"
197 raise err if tries == 0
199 logger.error "retrying in #{delay} seconds " \
200 "(#{tries < 0 ? 'infinite' : tries} tries left)"
206 # monitors children and receives signals forever
207 # (or until a termination signal is sent). This handles signals
208 # one-at-a-time time and we'll happily drop signals in case somebody
209 # is signalling us too often.
211 # this pipe is used to wake us up from select(2) in #join when signals
212 # are trapped. See trap_deferred
216 QUEUE_SIGS.each { |sig| trap_deferred(sig) }
217 trap(:CHLD) { |sig_nr| awaken_master }
219 logger.info "master process ready" # test_exec.rb relies on this message
226 maintain_worker_count if respawn
228 when :QUIT # graceful shutdown
230 when :TERM, :INT # immediate shutdown
233 when :USR1 # rotate logs
234 logger.info "master reopening logs..."
235 Unicorn::Util.reopen_logs
236 logger.info "master done reopening logs"
237 kill_each_worker(:USR1)
238 when :USR2 # exec binary, stay alive in case something went wrong
241 if Process.ppid == 1 || Process.getpgrp != $$
243 logger.info "gracefully stopping all workers"
244 kill_each_worker(:QUIT)
246 logger.info "SIGWINCH ignored because we're not daemonized"
249 self.worker_processes += 1
251 self.worker_processes -= 1 if self.worker_processes > 0
254 if config.config_file
256 redo # immediate reaping since we may have QUIT workers
257 else # exec binary and exit if there's no config file
258 logger.info "config_file not present, reexecuting binary"
267 logger.error "Unhandled master loop exception #{e.inspect}."
268 logger.error e.backtrace.join("\n")
271 stop # gracefully shutdown all workers on our way out
272 logger.info "master complete"
273 unlink_pid_safe(pid) if pid
276 # Terminates all workers, but does not exit master process
277 def stop(graceful = true)
279 kill_each_worker(graceful ? :QUIT : :TERM)
286 (timeleft -= step) > 0 and next
287 kill_each_worker(:KILL)
293 # list of signals we care about and trap in master.
294 QUEUE_SIGS = [ :WINCH, :QUIT, :INT, :TERM, :USR1, :USR2, :HUP,
297 # defer a signal for later processing in #join (master process)
298 def trap_deferred(signal)
299 trap(signal) do |sig_nr|
300 if SIG_QUEUE.size < 5
304 logger.error "ignoring SIG#{signal}, queue=#{SIG_QUEUE.inspect}"
309 # wait for a signal hander to wake us up and then consume the pipe
310 # Wake up every second anyways to run murder_lazy_workers
313 ready = IO.select([SELF_PIPE.first], nil, nil, 1) or return
314 ready.first && ready.first.first or return
315 loop { SELF_PIPE.first.read_nonblock(Const::CHUNK_SIZE) }
316 rescue Errno::EAGAIN, Errno::EINTR
322 SELF_PIPE.last.write_nonblock('.') # wakeup master process from select
323 rescue Errno::EAGAIN, Errno::EINTR
324 # pipe is full, master should wake up anyways
329 # reaps all unreaped workers
333 wpid, status = Process.waitpid2(-1, Process::WNOHANG)
335 if reexec_pid == wpid
336 logger.error "reaped #{status.inspect} exec()-ed"
338 self.pid = pid.chomp('.oldbin') if pid
341 worker = WORKERS.delete(wpid) and worker.tmp.close rescue nil
342 logger.info "reaped #{status.inspect} " \
343 "worker=#{worker.nr rescue 'unknown'}"
350 # reexecutes the START_CTX with a new binary
354 Process.kill(0, reexec_pid)
355 logger.error "reexec-ed child already running PID:#{reexec_pid}"
363 old_pid = "#{pid}.oldbin"
366 self.pid = old_pid # clear the path for a new pid file
368 logger.error "old PID:#{valid_pid?(old_pid)} running with " \
369 "existing pid=#{old_pid}, refusing rexec"
372 logger.error "error writing pid=#{old_pid} #{e.class} #{e.message}"
377 self.reexec_pid = fork do
378 listener_fds = LISTENERS.map { |sock| sock.fileno }
379 ENV['UNICORN_FD'] = listener_fds.join(',')
380 Dir.chdir(START_CTX[:cwd])
381 cmd = [ START_CTX[0] ].concat(START_CTX[:argv])
383 # avoid leaking FDs we don't know about, but let before_exec
384 # unset FD_CLOEXEC, if anything else in the app eventually
385 # relies on FD inheritence.
386 (3..1024).each do |io|
387 next if listener_fds.include?(io)
388 io = IO.for_fd(io) rescue nil
391 io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
393 logger.info "executing #{cmd.inspect} (in #{Dir.pwd})"
394 before_exec.call(self)
397 proc_name 'master (old)'
400 # forcibly terminate all workers that haven't checked in in timeout
401 # seconds. The timeout is implemented using an unlinked File
402 # shared between the parent process and each worker. The worker
403 # runs File#chmod to modify the ctime of the File. If the ctime
404 # is stale for >timeout seconds, then we'll kill the corresponding
406 def murder_lazy_workers
408 WORKERS.dup.each_pair do |wpid, worker|
412 logger.warn "worker=#{worker.nr} PID:#{wpid} stat error: #{e.inspect}"
413 kill_worker(:QUIT, wpid)
416 stat.mode == 0100000 and next
417 (diff = (Time.now - stat.ctime)) <= timeout and next
418 logger.error "worker=#{worker.nr} PID:#{wpid} timeout " \
419 "(#{diff}s > #{timeout}s), killing"
420 kill_worker(:KILL, wpid) # take no prisoners for timeout violations
424 def spawn_missing_workers
425 (0...worker_processes).each do |worker_nr|
426 WORKERS.values.include?(worker_nr) and next
428 Dir.chdir(START_CTX[:cwd])
429 rescue Errno::ENOENT => err
430 logger.fatal "#{err.inspect} (#{START_CTX[:cwd]})"
431 SIG_QUEUE << :QUIT # forcibly emulate SIGQUIT
434 worker = Worker.new(worker_nr, Unicorn::Util.tmpio)
435 before_fork.call(self, worker)
436 WORKERS[fork { worker_loop(worker) }] = worker
440 def maintain_worker_count
441 (off = WORKERS.size - worker_processes) == 0 and return
442 off < 0 and return spawn_missing_workers
443 WORKERS.dup.each_pair { |wpid,w|
444 w.nr >= worker_processes and kill_worker(:QUIT, wpid) rescue nil
448 # once a client is accepted, it is processed in its entirety here
449 # in 3 easy steps: read request, call app, write app response
450 def process_client(client)
451 client.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
452 response = app.call(env = REQUEST.read(client))
454 if 100 == response.first.to_i
455 client.write(Const::EXPECT_100_RESPONSE)
456 env.delete(Const::HTTP_EXPECT)
457 response = app.call(env)
459 HttpResponse.write(client, response, HttpRequest::PARSER.headers?)
460 # if we get any error, try to write something back to the client
461 # assuming we haven't closed the socket, but don't get hung up
462 # if the socket is already closed or broken. We'll always ensure
463 # the socket is closed at the end of this function
464 rescue EOFError,Errno::ECONNRESET,Errno::EPIPE,Errno::EINVAL,Errno::EBADF
465 client.write_nonblock(Const::ERROR_500_RESPONSE) rescue nil
466 client.close rescue nil
467 rescue HttpParserError # try to tell the client they're bad
468 client.write_nonblock(Const::ERROR_400_RESPONSE) rescue nil
469 client.close rescue nil
471 client.write_nonblock(Const::ERROR_500_RESPONSE) rescue nil
472 client.close rescue nil
473 logger.error "Read error: #{e.inspect}"
474 logger.error e.backtrace.join("\n")
477 # gets rid of stuff the worker has no business keeping track of
478 # to free some resources and drops all sig handlers.
479 # traps for USR1, USR2, and HUP may be set in the after_fork Proc
481 def init_worker_process(worker)
482 QUEUE_SIGS.each { |sig| trap(sig, nil) }
483 trap(:CHLD, 'DEFAULT')
485 proc_name "worker[#{worker.nr}]"
488 WORKERS.values.each { |other| other.tmp.close rescue nil }
490 LISTENERS.each { |sock| sock.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }
491 worker.tmp.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
492 after_fork.call(self, worker) # can drop perms
493 self.timeout /= 2.0 # halve it for select()
494 build_app! unless preload_app
497 def reopen_worker_logs(worker_nr)
498 logger.info "worker=#{worker_nr} reopening logs..."
499 Unicorn::Util.reopen_logs
500 logger.info "worker=#{worker_nr} done reopening logs"
504 # runs inside each forked worker, this sits around and waits
505 # for connections and doesn't die until the parent dies (or is
506 # given a INT, QUIT, or TERM signal)
507 def worker_loop(worker)
509 init_worker_process(worker)
510 nr = 0 # this becomes negative if we need to reopen logs
511 alive = worker.tmp # tmp is our lifeline to the master process
515 # closing anything we IO.select on will raise EBADF
516 trap(:USR1) { nr = -65536; SELF_PIPE.first.close rescue nil }
517 trap(:QUIT) { alive = nil; LISTENERS.each { |s| s.close rescue nil } }
518 [:TERM, :INT].each { |sig| trap(sig) { exit!(0) } } # instant shutdown
519 logger.info "worker=#{worker.nr} ready"
522 nr < 0 and reopen_worker_logs(worker.nr)
525 # we're a goner in timeout seconds anyways if alive.chmod
526 # breaks, so don't trap the exception. Using fchmod() since
527 # futimes() is not available in base Ruby and I very strongly
528 # prefer temporary files to be unlinked for security,
529 # performance and reliability reasons, so utime is out. No-op
530 # changes with chmod doesn't update ctime on all filesystems; so
531 # we change our counter each and every time (after process_client
532 # and before IO.select).
533 t == (ti = Time.now.to_i) or alive.chmod(t = ti)
537 process_client(sock.accept_nonblock)
539 t == (ti = Time.now.to_i) or alive.chmod(t = ti)
540 rescue Errno::EAGAIN, Errno::ECONNABORTED
545 # make the following bet: if we accepted clients this round,
546 # we're probably reasonably busy, so avoid calling select()
547 # and do a speculative accept_nonblock on ready listeners
548 # before we sleep again in select().
549 redo unless nr == 0 # (nr < 0) => reopen logs
551 ppid == Process.ppid or return
554 # timeout used so we can detect parent death:
555 ret = IO.select(LISTENERS, nil, SELF_PIPE, timeout) or redo
564 logger.error "Unhandled listen loop exception #{e.inspect}."
565 logger.error e.backtrace.join("\n")
570 # delivers a signal to a worker and fails gracefully if the worker
571 # is no longer running.
572 def kill_worker(signal, wpid)
574 Process.kill(signal, wpid)
576 worker = WORKERS.delete(wpid) and worker.tmp.close rescue nil
580 # delivers a signal to each worker
581 def kill_each_worker(signal)
582 WORKERS.keys.each { |wpid| kill_worker(signal, wpid) }
585 # unlinks a PID file at given +path+ if it contains the current PID
586 # useful as an at_exit handler.
587 def unlink_pid_safe(path)
588 (File.read(path).to_i == $$ and File.unlink(path)) rescue nil
591 # returns a PID if a given path contains a non-stale PID file,
594 if File.exist?(path) && (wpid = File.read(path).to_i) > 1
596 Process.kill(0, wpid)
606 logger.info "reloading config_file=#{config.config_file}"
607 config[:listeners].replace(init_listeners)
610 kill_each_worker(:QUIT)
611 Unicorn::Util.reopen_logs
613 build_app! if preload_app
614 logger.info "done reloading config_file=#{config.config_file}"
616 logger.error "error reloading config_file=#{config.config_file}: " \
617 "#{e.class} #{e.message}"
621 # returns an array of string names for the given listener array
622 def listener_names(listeners = LISTENERS)
623 listeners.map { |io| sock_name(io) }
627 if app.respond_to?(:arity) && app.arity == 0
628 if defined?(Gem) && Gem.respond_to?(:refresh)
629 logger.info "Refreshing Gem list"
637 $0 = ([ File.basename(START_CTX[0]), tag
638 ]).concat(START_CTX[:argv]).join(' ')
641 def redirect_io(io, path)
642 File.open(path, 'ab') { |fp| io.reopen(fp) } if path
647 SELF_PIPE.each { |io| io.close rescue nil }
648 SELF_PIPE.replace(IO.pipe)
649 SELF_PIPE.each { |io| io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }