2 require 'unicorn/socket_helper'
5 # Unicorn module containing all of the classes (include C extensions) for running
6 # a Unicorn web server. It contains a minimalist HTTP server with just enough
7 # functionality to service web application requests fast as possible.
9 autoload :Const, 'unicorn/const'
10 autoload :HttpRequest, 'unicorn/http_request'
11 autoload :HttpResponse, 'unicorn/http_response'
12 autoload :Configurator, 'unicorn/configurator'
13 autoload :TeeInput, 'unicorn/tee_input'
14 autoload :ChunkedReader, 'unicorn/chunked_reader'
15 autoload :TrailerParser, 'unicorn/trailer_parser'
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
114 config_listeners.each { |addr| listen(addr) }
115 raise ArgumentError, "no listeners" if LISTENERS.empty?
116 self.pid = config[:pid]
118 build_app! if preload_app
119 maintain_worker_count
123 # replaces current listener set with +listeners+. This will
124 # close the socket if it will not exist in the new listener set
125 def listeners=(listeners)
126 cur_names, dead_names = [], []
127 listener_names.each do |name|
129 # mark unlinked sockets as dead so we can rebind them
130 (File.socket?(name) ? cur_names : dead_names) << name
135 set_names = listener_names(listeners)
136 dead_names.concat(cur_names - set_names).uniq!
138 LISTENERS.delete_if do |io|
139 if dead_names.include?(sock_name(io))
140 IO_PURGATORY.delete_if do |pio|
141 pio.fileno == io.fileno && (pio.close rescue nil).nil? # true
143 (io.close rescue nil).nil? # true
145 set_server_sockopt(io, listener_opts[sock_name(io)])
150 (set_names - cur_names).each { |addr| listen(addr) }
153 def stdout_path=(path); redirect_io($stdout, path); end
154 def stderr_path=(path); redirect_io($stderr, path); end
156 alias_method :set_pid, :pid=
159 # sets the path for the PID file of the master process
162 if x = valid_pid?(path)
163 return path if pid && path == pid && x == $$
164 raise ArgumentError, "Already running on PID:#{x} " \
165 "(or pid=#{path} is stale)"
168 unlink_pid_safe(pid) if pid
169 File.open(path, 'wb') { |fp| fp.syswrite("#$$\n") } if path
173 # add a given address to the +listeners+ set, idempotently
174 # Allows workers to add a private, per-process listener via the
175 # after_fork hook. Very useful for debugging and testing.
176 def listen(address, opt = {}.merge(listener_opts[address] || {}))
177 return if String === address && listener_names.include?(address)
179 delay, tries = 0.5, 5
181 io = bind_listen(address, opt)
182 unless TCPServer === io || UNIXServer === io
186 logger.info "listening on addr=#{sock_name(io)} fd=#{io.fileno}"
189 rescue Errno::EADDRINUSE => err
190 logger.error "adding listener failed addr=#{address} (in use)"
191 raise err if tries == 0
193 logger.error "retrying in #{delay} seconds (#{tries} tries left)"
199 # monitors children and receives signals forever
200 # (or until a termination signal is sent). This handles signals
201 # one-at-a-time time and we'll happily drop signals in case somebody
202 # is signalling us too often.
204 # this pipe is used to wake us up from select(2) in #join when signals
205 # are trapped. See trap_deferred
209 QUEUE_SIGS.each { |sig| trap_deferred(sig) }
210 trap(:CHLD) { |sig_nr| awaken_master }
212 logger.info "master process ready" # test_exec.rb relies on this message
219 maintain_worker_count if respawn
221 when :QUIT # graceful shutdown
223 when :TERM, :INT # immediate shutdown
226 when :USR1 # rotate logs
227 logger.info "master reopening logs..."
228 Unicorn::Util.reopen_logs
229 logger.info "master done reopening logs"
230 kill_each_worker(:USR1)
231 when :USR2 # exec binary, stay alive in case something went wrong
234 if Process.ppid == 1 || Process.getpgrp != $$
236 logger.info "gracefully stopping all workers"
237 kill_each_worker(:QUIT)
239 logger.info "SIGWINCH ignored because we're not daemonized"
242 self.worker_processes += 1
244 self.worker_processes -= 1 if self.worker_processes > 0
247 if config.config_file
249 redo # immediate reaping since we may have QUIT workers
250 else # exec binary and exit if there's no config file
251 logger.info "config_file not present, reexecuting binary"
260 logger.error "Unhandled master loop exception #{e.inspect}."
261 logger.error e.backtrace.join("\n")
264 stop # gracefully shutdown all workers on our way out
265 logger.info "master complete"
266 unlink_pid_safe(pid) if pid
269 # Terminates all workers, but does not exit master process
270 def stop(graceful = true)
272 kill_each_worker(graceful ? :QUIT : :TERM)
279 (timeleft -= step) > 0 and next
280 kill_each_worker(:KILL)
286 # list of signals we care about and trap in master.
287 QUEUE_SIGS = [ :WINCH, :QUIT, :INT, :TERM, :USR1, :USR2, :HUP,
288 :TTIN, :TTOU ].freeze
290 # defer a signal for later processing in #join (master process)
291 def trap_deferred(signal)
292 trap(signal) do |sig_nr|
293 if SIG_QUEUE.size < 5
297 logger.error "ignoring SIG#{signal}, queue=#{SIG_QUEUE.inspect}"
302 # wait for a signal hander to wake us up and then consume the pipe
303 # Wake up every second anyways to run murder_lazy_workers
306 ready = IO.select([SELF_PIPE.first], nil, nil, 1) or return
307 ready.first && ready.first.first or return
308 loop { SELF_PIPE.first.read_nonblock(Const::CHUNK_SIZE) }
309 rescue Errno::EAGAIN, Errno::EINTR
315 SELF_PIPE.last.write_nonblock('.') # wakeup master process from select
316 rescue Errno::EAGAIN, Errno::EINTR
317 # pipe is full, master should wake up anyways
322 # reaps all unreaped workers
326 wpid, status = Process.waitpid2(-1, Process::WNOHANG)
328 if reexec_pid == wpid
329 logger.error "reaped #{status.inspect} exec()-ed"
331 self.pid = pid.chomp('.oldbin') if pid
334 worker = WORKERS.delete(wpid) and worker.tmp.close rescue nil
335 logger.info "reaped #{status.inspect} " \
336 "worker=#{worker.nr rescue 'unknown'}"
343 # reexecutes the START_CTX with a new binary
347 Process.kill(0, reexec_pid)
348 logger.error "reexec-ed child already running PID:#{reexec_pid}"
356 old_pid = "#{pid}.oldbin"
359 self.pid = old_pid # clear the path for a new pid file
361 logger.error "old PID:#{valid_pid?(old_pid)} running with " \
362 "existing pid=#{old_pid}, refusing rexec"
365 logger.error "error writing pid=#{old_pid} #{e.class} #{e.message}"
370 self.reexec_pid = fork do
371 listener_fds = LISTENERS.map { |sock| sock.fileno }
372 ENV['UNICORN_FD'] = listener_fds.join(',')
373 Dir.chdir(START_CTX[:cwd])
374 cmd = [ START_CTX[0] ].concat(START_CTX[:argv])
376 # avoid leaking FDs we don't know about, but let before_exec
377 # unset FD_CLOEXEC, if anything else in the app eventually
378 # relies on FD inheritence.
379 (3..1024).each do |io|
380 next if listener_fds.include?(io)
381 io = IO.for_fd(io) rescue nil
384 io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
386 logger.info "executing #{cmd.inspect} (in #{Dir.pwd})"
387 before_exec.call(self)
390 proc_name 'master (old)'
393 # forcibly terminate all workers that haven't checked in in timeout
394 # seconds. The timeout is implemented using an unlinked File
395 # shared between the parent process and each worker. The worker
396 # runs File#chmod to modify the ctime of the File. If the ctime
397 # is stale for >timeout seconds, then we'll kill the corresponding
399 def murder_lazy_workers
401 WORKERS.dup.each_pair do |wpid, worker|
405 logger.warn "worker=#{worker.nr} PID:#{wpid} stat error: #{e.inspect}"
406 kill_worker(:QUIT, wpid)
409 stat.mode == 0100000 and next
410 (diff = (Time.now - stat.ctime)) <= timeout and next
411 logger.error "worker=#{worker.nr} PID:#{wpid} timeout " \
412 "(#{diff}s > #{timeout}s), killing"
413 kill_worker(:KILL, wpid) # take no prisoners for timeout violations
417 def spawn_missing_workers
418 (0...worker_processes).each do |worker_nr|
419 WORKERS.values.include?(worker_nr) and next
421 Dir.chdir(START_CTX[:cwd])
422 rescue Errno::ENOENT => err
423 logger.fatal "#{err.inspect} (#{START_CTX[:cwd]})"
424 SIG_QUEUE << :QUIT # forcibly emulate SIGQUIT
427 worker = Worker.new(worker_nr, Unicorn::Util.tmpio)
428 before_fork.call(self, worker)
429 WORKERS[fork { worker_loop(worker) }] = worker
433 def maintain_worker_count
434 (off = WORKERS.size - worker_processes) == 0 and return
435 off < 0 and return spawn_missing_workers
436 WORKERS.dup.each_pair { |wpid,w|
437 w.nr >= worker_processes and kill_worker(:QUIT, wpid) rescue nil
441 # once a client is accepted, it is processed in its entirety here
442 # in 3 easy steps: read request, call app, write app response
443 def process_client(client)
444 client.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
445 response = app.call(env = REQUEST.read(client))
447 if 100 == response.first.to_i
448 client.write(Const::EXPECT_100_RESPONSE)
449 env.delete(Const::HTTP_EXPECT)
450 response = app.call(env)
453 HttpResponse.write(client, response)
454 # if we get any error, try to write something back to the client
455 # assuming we haven't closed the socket, but don't get hung up
456 # if the socket is already closed or broken. We'll always ensure
457 # the socket is closed at the end of this function
458 rescue EOFError,Errno::ECONNRESET,Errno::EPIPE,Errno::EINVAL,Errno::EBADF
459 client.write_nonblock(Const::ERROR_500_RESPONSE) rescue nil
460 client.close rescue nil
461 rescue HttpParserError # try to tell the client they're bad
462 client.write_nonblock(Const::ERROR_400_RESPONSE) rescue nil
463 client.close rescue nil
465 client.write_nonblock(Const::ERROR_500_RESPONSE) rescue nil
466 client.close rescue nil
467 logger.error "Read error: #{e.inspect}"
468 logger.error e.backtrace.join("\n")
471 # gets rid of stuff the worker has no business keeping track of
472 # to free some resources and drops all sig handlers.
473 # traps for USR1, USR2, and HUP may be set in the after_fork Proc
475 def init_worker_process(worker)
476 QUEUE_SIGS.each { |sig| trap(sig, nil) }
477 trap(:CHLD, 'DEFAULT')
479 proc_name "worker[#{worker.nr}]"
482 WORKERS.values.each { |other| other.tmp.close rescue nil }
484 LISTENERS.each { |sock| sock.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }
485 worker.tmp.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
486 after_fork.call(self, worker) # can drop perms
487 self.timeout /= 2.0 # halve it for select()
488 build_app! unless preload_app
491 def reopen_worker_logs(worker_nr)
492 logger.info "worker=#{worker_nr} reopening logs..."
493 Unicorn::Util.reopen_logs
494 logger.info "worker=#{worker_nr} done reopening logs"
498 # runs inside each forked worker, this sits around and waits
499 # for connections and doesn't die until the parent dies (or is
500 # given a INT, QUIT, or TERM signal)
501 def worker_loop(worker)
503 init_worker_process(worker)
504 nr = 0 # this becomes negative if we need to reopen logs
505 alive = worker.tmp # tmp is our lifeline to the master process
509 # closing anything we IO.select on will raise EBADF
510 trap(:USR1) { nr = -65536; SELF_PIPE.first.close rescue nil }
511 trap(:QUIT) { alive = nil; LISTENERS.each { |s| s.close rescue nil } }
512 [:TERM, :INT].each { |sig| trap(sig) { exit!(0) } } # instant shutdown
513 logger.info "worker=#{worker.nr} ready"
516 nr < 0 and reopen_worker_logs(worker.nr)
519 # we're a goner in timeout seconds anyways if alive.chmod
520 # breaks, so don't trap the exception. Using fchmod() since
521 # futimes() is not available in base Ruby and I very strongly
522 # prefer temporary files to be unlinked for security,
523 # performance and reliability reasons, so utime is out. No-op
524 # changes with chmod doesn't update ctime on all filesystems; so
525 # we change our counter each and every time (after process_client
526 # and before IO.select).
527 t == (ti = Time.now.to_i) or alive.chmod(t = ti)
531 process_client(sock.accept_nonblock)
533 t == (ti = Time.now.to_i) or alive.chmod(t = ti)
534 rescue Errno::EAGAIN, Errno::ECONNABORTED
539 # make the following bet: if we accepted clients this round,
540 # we're probably reasonably busy, so avoid calling select()
541 # and do a speculative accept_nonblock on every listener
542 # before we sleep again in select().
543 redo unless nr == 0 # (nr < 0) => reopen logs
545 ppid == Process.ppid or return
548 # timeout used so we can detect parent death:
549 ret = IO.select(LISTENERS, nil, SELF_PIPE, timeout) or redo
558 logger.error "Unhandled listen loop exception #{e.inspect}."
559 logger.error e.backtrace.join("\n")
564 # delivers a signal to a worker and fails gracefully if the worker
565 # is no longer running.
566 def kill_worker(signal, wpid)
568 Process.kill(signal, wpid)
570 worker = WORKERS.delete(wpid) and worker.tmp.close rescue nil
574 # delivers a signal to each worker
575 def kill_each_worker(signal)
576 WORKERS.keys.each { |wpid| kill_worker(signal, wpid) }
579 # unlinks a PID file at given +path+ if it contains the current PID
580 # useful as an at_exit handler.
581 def unlink_pid_safe(path)
582 (File.read(path).to_i == $$ and File.unlink(path)) rescue nil
585 # returns a PID if a given path contains a non-stale PID file,
588 if File.exist?(path) && (wpid = File.read(path).to_i) > 1
590 Process.kill(0, wpid)
600 logger.info "reloading config_file=#{config.config_file}"
601 config[:listeners].replace(init_listeners)
604 kill_each_worker(:QUIT)
605 Unicorn::Util.reopen_logs
607 build_app! if preload_app
608 logger.info "done reloading config_file=#{config.config_file}"
610 logger.error "error reloading config_file=#{config.config_file}: " \
611 "#{e.class} #{e.message}"
615 # returns an array of string names for the given listener array
616 def listener_names(listeners = LISTENERS)
617 listeners.map { |io| sock_name(io) }
621 if app.respond_to?(:arity) && app.arity == 0
622 if defined?(Gem) && Gem.respond_to?(:refresh)
623 logger.info "Refreshing Gem list"
631 $0 = ([ File.basename(START_CTX[0]), tag
632 ]).concat(START_CTX[:argv]).join(' ')
635 def redirect_io(io, path)
636 File.open(path, 'a') { |fp| io.reopen(fp) } if path
641 SELF_PIPE.each { |io| io.close rescue nil }
642 SELF_PIPE.replace(IO.pipe)
643 SELF_PIPE.each { |io| io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }