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'
18 Z = '' # the stock empty string we use everywhere...
19 Z.force_encoding(Encoding::BINARY) if Z.respond_to?(:force_encoding)
23 def run(app, options = {})
24 HttpServer.new(app, options).start.join
28 # This is the process manager of Unicorn. This manages worker
29 # processes which in turn handle the I/O and application process.
30 # Listener sockets are started in the master process and shared with
31 # forked worker children.
33 class HttpServer < Struct.new(:listener_opts, :timeout, :worker_processes,
34 :before_fork, :after_fork, :before_exec,
35 :logger, :pid, :app, :preload_app,
36 :reexec_pid, :orig_app, :init_listeners,
38 include ::Unicorn::SocketHelper
40 # prevents IO objects in here from being GC-ed
43 # all bound listener sockets
46 # This hash maps PIDs to Workers
49 # See: http://cr.yp.to/docs/selfpipe.html
52 # signal queue used for self-piping
55 # constant lookups are faster and we're single-threaded/non-reentrant
56 REQUEST = HttpRequest.new
58 # We populate this at startup so we can figure out how to reexecute
59 # and upgrade the currently running instance of Unicorn
61 :argv => ARGV.map { |arg| arg.dup },
62 # don't rely on Dir.pwd here since it's not symlink-aware, and
63 # symlink dirs are the default with Capistrano...
64 :cwd => `/bin/sh -c pwd`.chomp("\n"),
68 class Worker < Struct.new(:nr, :tmp)
69 # worker objects may be compared to just plain numbers
75 # Creates a working server on host:port (strange things happen if
76 # port isn't a Number). Use HttpServer::run to start the server and
77 # HttpServer.run.join to join the thread that's processing
78 # incoming requests on the socket.
79 def initialize(app, options = {})
82 self.init_listeners = options[:listeners] ? options[:listeners].dup : []
83 self.config = Configurator.new(options.merge(:use_defaults => true))
84 self.listener_opts = {}
85 config.commit!(self, :skip => [:listeners, :pid])
89 # Runs the thing. Returns self so you can run join on it
91 BasicSocket.do_not_reverse_lookup = true
93 # inherit sockets from parents, they need to be plain Socket objects
94 # before they become UNIXServer or TCPServer
95 inherited = ENV['UNICORN_FD'].to_s.split(/,/).map do |fd|
96 io = Socket.for_fd(fd.to_i)
97 set_server_sockopt(io, listener_opts[sock_name(io)])
99 logger.info "inherited addr=#{sock_name(io)} fd=#{fd}"
103 config_listeners = config[:listeners].dup
104 LISTENERS.replace(inherited)
106 # we start out with generic Socket objects that get cast to either
107 # TCPServer or UNIXServer objects; but since the Socket objects
108 # share the same OS-level file descriptor as the higher-level *Server
109 # objects; we need to prevent Socket objects from being garbage-collected
110 config_listeners -= listener_names
111 if config_listeners.empty? && LISTENERS.empty?
112 config_listeners << Unicorn::Const::DEFAULT_LISTEN
113 init_listeners << Unicorn::Const::DEFAULT_LISTEN
114 START_CTX[:argv] << "-l#{Unicorn::Const::DEFAULT_LISTEN}"
116 config_listeners.each { |addr| listen(addr) }
117 raise ArgumentError, "no listeners" if LISTENERS.empty?
118 self.pid = config[:pid]
120 build_app! if preload_app
121 maintain_worker_count
125 # replaces current listener set with +listeners+. This will
126 # close the socket if it will not exist in the new listener set
127 def listeners=(listeners)
128 cur_names, dead_names = [], []
129 listener_names.each do |name|
131 # mark unlinked sockets as dead so we can rebind them
132 (File.socket?(name) ? cur_names : dead_names) << name
137 set_names = listener_names(listeners)
138 dead_names.concat(cur_names - set_names).uniq!
140 LISTENERS.delete_if do |io|
141 if dead_names.include?(sock_name(io))
142 IO_PURGATORY.delete_if do |pio|
143 pio.fileno == io.fileno && (pio.close rescue nil).nil? # true
145 (io.close rescue nil).nil? # true
147 set_server_sockopt(io, listener_opts[sock_name(io)])
152 (set_names - cur_names).each { |addr| listen(addr) }
155 def stdout_path=(path); redirect_io($stdout, path); end
156 def stderr_path=(path); redirect_io($stderr, path); end
158 alias_method :set_pid, :pid=
161 # sets the path for the PID file of the master process
164 if x = valid_pid?(path)
165 return path if pid && path == pid && x == $$
166 raise ArgumentError, "Already running on PID:#{x} " \
167 "(or pid=#{path} is stale)"
170 unlink_pid_safe(pid) if pid
171 File.open(path, 'wb') { |fp| fp.syswrite("#$$\n") } if path
175 # add a given address to the +listeners+ set, idempotently
176 # Allows workers to add a private, per-process listener via the
177 # after_fork hook. Very useful for debugging and testing.
178 def listen(address, opt = {}.merge(listener_opts[address] || {}))
179 return if String === address && listener_names.include?(address)
181 delay, tries = 0.5, 5
183 io = bind_listen(address, opt)
184 unless TCPServer === io || UNIXServer === io
188 logger.info "listening on addr=#{sock_name(io)} fd=#{io.fileno}"
191 rescue Errno::EADDRINUSE => err
192 logger.error "adding listener failed addr=#{address} (in use)"
193 raise err if tries == 0
195 logger.error "retrying in #{delay} seconds (#{tries} tries left)"
201 # monitors children and receives signals forever
202 # (or until a termination signal is sent). This handles signals
203 # one-at-a-time time and we'll happily drop signals in case somebody
204 # is signalling us too often.
206 # this pipe is used to wake us up from select(2) in #join when signals
207 # are trapped. See trap_deferred
211 QUEUE_SIGS.each { |sig| trap_deferred(sig) }
212 trap(:CHLD) { |sig_nr| awaken_master }
214 logger.info "master process ready" # test_exec.rb relies on this message
221 maintain_worker_count if respawn
223 when :QUIT # graceful shutdown
225 when :TERM, :INT # immediate shutdown
228 when :USR1 # rotate logs
229 logger.info "master reopening logs..."
230 Unicorn::Util.reopen_logs
231 logger.info "master done reopening logs"
232 kill_each_worker(:USR1)
233 when :USR2 # exec binary, stay alive in case something went wrong
236 if Process.ppid == 1 || Process.getpgrp != $$
238 logger.info "gracefully stopping all workers"
239 kill_each_worker(:QUIT)
241 logger.info "SIGWINCH ignored because we're not daemonized"
244 self.worker_processes += 1
246 self.worker_processes -= 1 if self.worker_processes > 0
249 if config.config_file
251 redo # immediate reaping since we may have QUIT workers
252 else # exec binary and exit if there's no config file
253 logger.info "config_file not present, reexecuting binary"
262 logger.error "Unhandled master loop exception #{e.inspect}."
263 logger.error e.backtrace.join("\n")
266 stop # gracefully shutdown all workers on our way out
267 logger.info "master complete"
268 unlink_pid_safe(pid) if pid
271 # Terminates all workers, but does not exit master process
272 def stop(graceful = true)
274 kill_each_worker(graceful ? :QUIT : :TERM)
281 (timeleft -= step) > 0 and next
282 kill_each_worker(:KILL)
288 # list of signals we care about and trap in master.
289 QUEUE_SIGS = [ :WINCH, :QUIT, :INT, :TERM, :USR1, :USR2, :HUP,
292 # defer a signal for later processing in #join (master process)
293 def trap_deferred(signal)
294 trap(signal) do |sig_nr|
295 if SIG_QUEUE.size < 5
299 logger.error "ignoring SIG#{signal}, queue=#{SIG_QUEUE.inspect}"
304 # wait for a signal hander to wake us up and then consume the pipe
305 # Wake up every second anyways to run murder_lazy_workers
308 ready = IO.select([SELF_PIPE.first], nil, nil, 1) or return
309 ready.first && ready.first.first or return
310 loop { SELF_PIPE.first.read_nonblock(Const::CHUNK_SIZE) }
311 rescue Errno::EAGAIN, Errno::EINTR
317 SELF_PIPE.last.write_nonblock('.') # wakeup master process from select
318 rescue Errno::EAGAIN, Errno::EINTR
319 # pipe is full, master should wake up anyways
324 # reaps all unreaped workers
328 wpid, status = Process.waitpid2(-1, Process::WNOHANG)
330 if reexec_pid == wpid
331 logger.error "reaped #{status.inspect} exec()-ed"
333 self.pid = pid.chomp('.oldbin') if pid
336 worker = WORKERS.delete(wpid) and worker.tmp.close rescue nil
337 logger.info "reaped #{status.inspect} " \
338 "worker=#{worker.nr rescue 'unknown'}"
345 # reexecutes the START_CTX with a new binary
349 Process.kill(0, reexec_pid)
350 logger.error "reexec-ed child already running PID:#{reexec_pid}"
358 old_pid = "#{pid}.oldbin"
361 self.pid = old_pid # clear the path for a new pid file
363 logger.error "old PID:#{valid_pid?(old_pid)} running with " \
364 "existing pid=#{old_pid}, refusing rexec"
367 logger.error "error writing pid=#{old_pid} #{e.class} #{e.message}"
372 self.reexec_pid = fork do
373 listener_fds = LISTENERS.map { |sock| sock.fileno }
374 ENV['UNICORN_FD'] = listener_fds.join(',')
375 Dir.chdir(START_CTX[:cwd])
376 cmd = [ START_CTX[0] ].concat(START_CTX[:argv])
378 # avoid leaking FDs we don't know about, but let before_exec
379 # unset FD_CLOEXEC, if anything else in the app eventually
380 # relies on FD inheritence.
381 (3..1024).each do |io|
382 next if listener_fds.include?(io)
383 io = IO.for_fd(io) rescue nil
386 io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
388 logger.info "executing #{cmd.inspect} (in #{Dir.pwd})"
389 before_exec.call(self)
392 proc_name 'master (old)'
395 # forcibly terminate all workers that haven't checked in in timeout
396 # seconds. The timeout is implemented using an unlinked File
397 # shared between the parent process and each worker. The worker
398 # runs File#chmod to modify the ctime of the File. If the ctime
399 # is stale for >timeout seconds, then we'll kill the corresponding
401 def murder_lazy_workers
403 WORKERS.dup.each_pair do |wpid, worker|
407 logger.warn "worker=#{worker.nr} PID:#{wpid} stat error: #{e.inspect}"
408 kill_worker(:QUIT, wpid)
411 stat.mode == 0100000 and next
412 (diff = (Time.now - stat.ctime)) <= timeout and next
413 logger.error "worker=#{worker.nr} PID:#{wpid} timeout " \
414 "(#{diff}s > #{timeout}s), killing"
415 kill_worker(:KILL, wpid) # take no prisoners for timeout violations
419 def spawn_missing_workers
420 (0...worker_processes).each do |worker_nr|
421 WORKERS.values.include?(worker_nr) and next
423 Dir.chdir(START_CTX[:cwd])
424 rescue Errno::ENOENT => err
425 logger.fatal "#{err.inspect} (#{START_CTX[:cwd]})"
426 SIG_QUEUE << :QUIT # forcibly emulate SIGQUIT
429 worker = Worker.new(worker_nr, Unicorn::Util.tmpio)
430 before_fork.call(self, worker)
431 WORKERS[fork { worker_loop(worker) }] = worker
435 def maintain_worker_count
436 (off = WORKERS.size - worker_processes) == 0 and return
437 off < 0 and return spawn_missing_workers
438 WORKERS.dup.each_pair { |wpid,w|
439 w.nr >= worker_processes and kill_worker(:QUIT, wpid) rescue nil
443 # once a client is accepted, it is processed in its entirety here
444 # in 3 easy steps: read request, call app, write app response
445 def process_client(client)
446 client.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
447 response = app.call(env = REQUEST.read(client))
449 if 100 == response.first.to_i
450 client.write(Const::EXPECT_100_RESPONSE)
451 env.delete(Const::HTTP_EXPECT)
452 response = app.call(env)
454 HttpResponse.write(client, response, HttpRequest::PARSER.headers?)
455 # if we get any error, try to write something back to the client
456 # assuming we haven't closed the socket, but don't get hung up
457 # if the socket is already closed or broken. We'll always ensure
458 # the socket is closed at the end of this function
459 rescue EOFError,Errno::ECONNRESET,Errno::EPIPE,Errno::EINVAL,Errno::EBADF
460 client.write_nonblock(Const::ERROR_500_RESPONSE) rescue nil
461 client.close rescue nil
462 rescue HttpParserError # try to tell the client they're bad
463 client.write_nonblock(Const::ERROR_400_RESPONSE) rescue nil
464 client.close rescue nil
466 client.write_nonblock(Const::ERROR_500_RESPONSE) rescue nil
467 client.close rescue nil
468 logger.error "Read error: #{e.inspect}"
469 logger.error e.backtrace.join("\n")
472 # gets rid of stuff the worker has no business keeping track of
473 # to free some resources and drops all sig handlers.
474 # traps for USR1, USR2, and HUP may be set in the after_fork Proc
476 def init_worker_process(worker)
477 QUEUE_SIGS.each { |sig| trap(sig, nil) }
478 trap(:CHLD, 'DEFAULT')
480 proc_name "worker[#{worker.nr}]"
483 WORKERS.values.each { |other| other.tmp.close rescue nil }
485 LISTENERS.each { |sock| sock.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }
486 worker.tmp.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
487 after_fork.call(self, worker) # can drop perms
488 self.timeout /= 2.0 # halve it for select()
489 build_app! unless preload_app
492 def reopen_worker_logs(worker_nr)
493 logger.info "worker=#{worker_nr} reopening logs..."
494 Unicorn::Util.reopen_logs
495 logger.info "worker=#{worker_nr} done reopening logs"
499 # runs inside each forked worker, this sits around and waits
500 # for connections and doesn't die until the parent dies (or is
501 # given a INT, QUIT, or TERM signal)
502 def worker_loop(worker)
504 init_worker_process(worker)
505 nr = 0 # this becomes negative if we need to reopen logs
506 alive = worker.tmp # tmp is our lifeline to the master process
510 # closing anything we IO.select on will raise EBADF
511 trap(:USR1) { nr = -65536; SELF_PIPE.first.close rescue nil }
512 trap(:QUIT) { alive = nil; LISTENERS.each { |s| s.close rescue nil } }
513 [:TERM, :INT].each { |sig| trap(sig) { exit!(0) } } # instant shutdown
514 logger.info "worker=#{worker.nr} ready"
517 nr < 0 and reopen_worker_logs(worker.nr)
520 # we're a goner in timeout seconds anyways if alive.chmod
521 # breaks, so don't trap the exception. Using fchmod() since
522 # futimes() is not available in base Ruby and I very strongly
523 # prefer temporary files to be unlinked for security,
524 # performance and reliability reasons, so utime is out. No-op
525 # changes with chmod doesn't update ctime on all filesystems; so
526 # we change our counter each and every time (after process_client
527 # and before IO.select).
528 t == (ti = Time.now.to_i) or alive.chmod(t = ti)
532 process_client(sock.accept_nonblock)
534 t == (ti = Time.now.to_i) or alive.chmod(t = ti)
535 rescue Errno::EAGAIN, Errno::ECONNABORTED
540 # make the following bet: if we accepted clients this round,
541 # we're probably reasonably busy, so avoid calling select()
542 # and do a speculative accept_nonblock on ready listeners
543 # before we sleep again in select().
544 redo unless nr == 0 # (nr < 0) => reopen logs
546 ppid == Process.ppid or return
549 # timeout used so we can detect parent death:
550 ret = IO.select(LISTENERS, nil, SELF_PIPE, timeout) or redo
559 logger.error "Unhandled listen loop exception #{e.inspect}."
560 logger.error e.backtrace.join("\n")
565 # delivers a signal to a worker and fails gracefully if the worker
566 # is no longer running.
567 def kill_worker(signal, wpid)
569 Process.kill(signal, wpid)
571 worker = WORKERS.delete(wpid) and worker.tmp.close rescue nil
575 # delivers a signal to each worker
576 def kill_each_worker(signal)
577 WORKERS.keys.each { |wpid| kill_worker(signal, wpid) }
580 # unlinks a PID file at given +path+ if it contains the current PID
581 # useful as an at_exit handler.
582 def unlink_pid_safe(path)
583 (File.read(path).to_i == $$ and File.unlink(path)) rescue nil
586 # returns a PID if a given path contains a non-stale PID file,
589 if File.exist?(path) && (wpid = File.read(path).to_i) > 1
591 Process.kill(0, wpid)
601 logger.info "reloading config_file=#{config.config_file}"
602 config[:listeners].replace(init_listeners)
605 kill_each_worker(:QUIT)
606 Unicorn::Util.reopen_logs
608 build_app! if preload_app
609 logger.info "done reloading config_file=#{config.config_file}"
611 logger.error "error reloading config_file=#{config.config_file}: " \
612 "#{e.class} #{e.message}"
616 # returns an array of string names for the given listener array
617 def listener_names(listeners = LISTENERS)
618 listeners.map { |io| sock_name(io) }
622 if app.respond_to?(:arity) && app.arity == 0
623 if defined?(Gem) && Gem.respond_to?(:refresh)
624 logger.info "Refreshing Gem list"
632 $0 = ([ File.basename(START_CTX[0]), tag
633 ]).concat(START_CTX[:argv]).join(' ')
636 def redirect_io(io, path)
637 File.open(path, 'ab') { |fp| io.reopen(fp) } if path
642 SELF_PIPE.each { |io| io.close rescue nil }
643 SELF_PIPE.replace(IO.pipe)
644 SELF_PIPE.each { |io| io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }