3 require 'unicorn/socket_helper'
4 require 'unicorn/const'
5 require 'unicorn/http_request'
6 require 'unicorn/http_response'
7 require 'unicorn/configurator'
10 # Unicorn module containing all of the classes (include C extensions) for running
11 # a Unicorn web server. It contains a minimalist HTTP server with just enough
12 # functionality to service web application requests fast as possible.
15 def run(app, options = {})
16 HttpServer.new(app, options).start.join
20 # This is the process manager of Unicorn. This manages worker
21 # processes which in turn handle the I/O and application process.
22 # Listener sockets are started in the master process and shared with
23 # forked worker children.
26 include ::Unicorn::SocketHelper
28 # prevents IO objects in here from being GC-ed
31 # all bound listener sockets
34 # This hash maps PIDs to Workers
37 # See: http://cr.yp.to/docs/selfpipe.html
40 # signal queue used for self-piping
43 # We populate this at startup so we can figure out how to reexecute
44 # and upgrade the currently running instance of Unicorn
46 :argv => ARGV.map { |arg| arg.dup },
47 # don't rely on Dir.pwd here since it's not symlink-aware, and
48 # symlink dirs are the default with Capistrano...
49 :cwd => `/bin/sh -c pwd`.chomp("\n"),
53 Worker = Struct.new(:nr, :tempfile) unless defined?(Worker)
55 # worker objects may be compared to just plain numbers
61 # Creates a working server on host:port (strange things happen if
62 # port isn't a Number). Use HttpServer::run to start the server and
63 # HttpServer.run.join to join the thread that's processing
64 # incoming requests on the socket.
65 def initialize(app, options = {})
69 @init_listeners = options[:listeners] ? options[:listeners].dup : []
70 @config = Configurator.new(options.merge(:use_defaults => true))
72 @config.commit!(self, :skip => [:listeners, :pid])
73 @request = HttpRequest.new(@logger)
76 # Runs the thing. Returns self so you can run join on it
78 BasicSocket.do_not_reverse_lookup = true
80 # inherit sockets from parents, they need to be plain Socket objects
81 # before they become UNIXServer or TCPServer
82 inherited = ENV['UNICORN_FD'].to_s.split(/,/).map do |fd|
83 io = Socket.for_fd(fd.to_i)
84 set_server_sockopt(io, @listener_opts[sock_name(io)])
86 logger.info "inherited addr=#{sock_name(io)} fd=#{fd}"
90 config_listeners = @config[:listeners].dup
91 LISTENERS.replace(inherited)
93 # we start out with generic Socket objects that get cast to either
94 # TCPServer or UNIXServer objects; but since the Socket objects
95 # share the same OS-level file descriptor as the higher-level *Server
96 # objects; we need to prevent Socket objects from being garbage-collected
97 config_listeners -= listener_names
98 if config_listeners.empty? && LISTENERS.empty?
99 config_listeners << Unicorn::Const::DEFAULT_LISTEN
101 config_listeners.each { |addr| listen(addr) }
102 raise ArgumentError, "no listeners" if LISTENERS.empty?
103 self.pid = @config[:pid]
104 build_app! if @preload_app
105 maintain_worker_count
109 # replaces current listener set with +listeners+. This will
110 # close the socket if it will not exist in the new listener set
111 def listeners=(listeners)
112 cur_names, dead_names = [], []
113 listener_names.each do |name|
115 # mark unlinked sockets as dead so we can rebind them
116 (File.socket?(name) ? cur_names : dead_names) << name
121 set_names = listener_names(listeners)
122 dead_names += cur_names - set_names
125 LISTENERS.delete_if do |io|
126 if dead_names.include?(sock_name(io))
127 IO_PURGATORY.delete_if do |pio|
128 pio.fileno == io.fileno && (pio.close rescue nil).nil? # true
130 (io.close rescue nil).nil? # true
132 set_server_sockopt(io, @listener_opts[sock_name(io)])
137 (set_names - cur_names).each { |addr| listen(addr) }
140 def stdout_path=(path); redirect_io($stdout, path); end
141 def stderr_path=(path); redirect_io($stderr, path); end
143 # sets the path for the PID file of the master process
146 if x = valid_pid?(path)
147 return path if @pid && path == @pid && x == $$
148 raise ArgumentError, "Already running on PID:#{x} " \
149 "(or pid=#{path} is stale)"
152 unlink_pid_safe(@pid) if @pid
153 File.open(path, 'wb') { |fp| fp.syswrite("#$$\n") } if path
157 # add a given address to the +listeners+ set, idempotently
158 # Allows workers to add a private, per-process listener via the
159 # @after_fork hook. Very useful for debugging and testing.
160 def listen(address, opt = {}.merge(@listener_opts[address] || {}))
161 return if String === address && listener_names.include?(address)
163 if io = bind_listen(address, opt)
164 unless TCPServer === io || UNIXServer === io
168 logger.info "listening on addr=#{sock_name(io)} fd=#{io.fileno}"
171 logger.error "adding listener failed addr=#{address} (in use)"
172 raise Errno::EADDRINUSE, address
176 # monitors children and receives signals forever
177 # (or until a termination signal is sent). This handles signals
178 # one-at-a-time time and we'll happily drop signals in case somebody
179 # is signalling us too often.
181 # this pipe is used to wake us up from select(2) in #join when signals
182 # are trapped. See trap_deferred
186 QUEUE_SIGS.each { |sig| trap_deferred(sig) }
187 trap(:CHLD) { |sig_nr| awaken_master }
189 logger.info "master process ready" # test_exec.rb relies on this message
196 maintain_worker_count if respawn
198 when :QUIT # graceful shutdown
200 when :TERM, :INT # immediate shutdown
203 when :USR1 # rotate logs
204 logger.info "master reopening logs..."
205 Unicorn::Util.reopen_logs
206 logger.info "master done reopening logs"
207 kill_each_worker(:USR1)
208 when :USR2 # exec binary, stay alive in case something went wrong
211 if Process.ppid == 1 || Process.getpgrp != $$
213 logger.info "gracefully stopping all workers"
214 kill_each_worker(:QUIT)
216 logger.info "SIGWINCH ignored because we're not daemonized"
219 @worker_processes += 1
221 @worker_processes -= 1 if @worker_processes > 0
224 if @config.config_file
226 redo # immediate reaping since we may have QUIT workers
227 else # exec binary and exit if there's no config file
228 logger.info "config_file not present, reexecuting binary"
237 logger.error "Unhandled master loop exception #{e.inspect}."
238 logger.error e.backtrace.join("\n")
241 stop # gracefully shutdown all workers on our way out
242 logger.info "master complete"
243 unlink_pid_safe(@pid) if @pid
246 # Terminates all workers, but does not exit master process
247 def stop(graceful = true)
248 kill_each_worker(graceful ? :QUIT : :TERM)
255 (timeleft -= step) > 0 and next
256 kill_each_worker(:KILL)
264 # list of signals we care about and trap in master.
265 QUEUE_SIGS = [ :WINCH, :QUIT, :INT, :TERM, :USR1, :USR2, :HUP,
266 :TTIN, :TTOU ].freeze
268 # defer a signal for later processing in #join (master process)
269 def trap_deferred(signal)
270 trap(signal) do |sig_nr|
271 if SIG_QUEUE.size < 5
275 logger.error "ignoring SIG#{signal}, queue=#{SIG_QUEUE.inspect}"
280 # wait for a signal hander to wake us up and then consume the pipe
281 # Wake up every second anyways to run murder_lazy_workers
284 ready = IO.select([SELF_PIPE.first], nil, nil, 1) or return
285 ready.first && ready.first.first or return
286 loop { SELF_PIPE.first.read_nonblock(Const::CHUNK_SIZE) }
287 rescue Errno::EAGAIN, Errno::EINTR
293 SELF_PIPE.last.write_nonblock('.') # wakeup master process from select
294 rescue Errno::EAGAIN, Errno::EINTR
295 # pipe is full, master should wake up anyways
300 # reaps all unreaped workers
304 pid, status = Process.waitpid2(-1, Process::WNOHANG)
306 if @reexec_pid == pid
307 logger.error "reaped #{status.inspect} exec()-ed"
309 self.pid = @pid.chomp('.oldbin') if @pid
312 worker = WORKERS.delete(pid)
313 worker.tempfile.close rescue nil
314 logger.info "reaped #{status.inspect} " \
315 "worker=#{worker.nr rescue 'unknown'}"
322 # reexecutes the START_CTX with a new binary
326 Process.kill(0, @reexec_pid)
327 logger.error "reexec-ed child already running PID:#{@reexec_pid}"
335 old_pid = "#{@pid}.oldbin"
338 self.pid = old_pid # clear the path for a new pid file
340 logger.error "old PID:#{valid_pid?(old_pid)} running with " \
341 "existing pid=#{old_pid}, refusing rexec"
344 logger.error "error writing pid=#{old_pid} #{e.class} #{e.message}"
349 @reexec_pid = fork do
350 listener_fds = LISTENERS.map { |sock| sock.fileno }
351 ENV['UNICORN_FD'] = listener_fds.join(',')
352 Dir.chdir(START_CTX[:cwd])
353 cmd = [ START_CTX[:zero] ] + START_CTX[:argv]
355 # avoid leaking FDs we don't know about, but let before_exec
356 # unset FD_CLOEXEC, if anything else in the app eventually
357 # relies on FD inheritence.
358 (3..1024).each do |io|
359 next if listener_fds.include?(io)
360 io = IO.for_fd(io) rescue nil
363 io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
365 logger.info "executing #{cmd.inspect} (in #{Dir.pwd})"
366 @before_exec.call(self)
369 proc_name 'master (old)'
372 # forcibly terminate all workers that haven't checked in in @timeout
373 # seconds. The timeout is implemented using an unlinked tempfile
374 # shared between the parent process and each worker. The worker
375 # runs File#chmod to modify the ctime of the tempfile. If the ctime
376 # is stale for >@timeout seconds, then we'll kill the corresponding
378 def murder_lazy_workers
379 WORKERS.each_pair do |pid, worker|
380 Time.now - worker.tempfile.ctime <= @timeout and next
381 logger.error "worker=#{worker.nr} PID:#{pid} is too old, killing"
382 kill_worker(:KILL, pid) # take no prisoners for @timeout violations
383 worker.tempfile.close rescue nil
387 def spawn_missing_workers
388 (0...@worker_processes).each do |worker_nr|
389 WORKERS.values.include?(worker_nr) and next
391 Dir.chdir(START_CTX[:cwd])
392 rescue Errno::ENOENT => err
393 logger.fatal "#{err.inspect} (#{START_CTX[:cwd]})"
394 SIG_QUEUE << :QUIT # forcibly emulate SIGQUIT
397 tempfile = Tempfile.new(nil) # as short as possible to save dir space
398 tempfile.unlink # don't allow other processes to find or see it
399 worker = Worker.new(worker_nr, tempfile)
400 @before_fork.call(self, worker)
401 pid = fork { worker_loop(worker) }
402 WORKERS[pid] = worker
406 def maintain_worker_count
407 (off = WORKERS.size - @worker_processes) == 0 and return
408 off < 0 and return spawn_missing_workers
409 WORKERS.each_pair { |pid,w|
410 w.nr >= @worker_processes and kill_worker(:QUIT, pid) rescue nil
414 # once a client is accepted, it is processed in its entirety here
415 # in 3 easy steps: read request, call app, write app response
416 def process_client(client)
417 HttpResponse.write(client, @app.call(@request.read(client)))
418 # if we get any error, try to write something back to the client
419 # assuming we haven't closed the socket, but don't get hung up
420 # if the socket is already closed or broken. We'll always ensure
421 # the socket is closed at the end of this function
422 rescue EOFError,Errno::ECONNRESET,Errno::EPIPE,Errno::EINVAL,Errno::EBADF
423 client.write_nonblock(Const::ERROR_500_RESPONSE) rescue nil
424 client.close rescue nil
425 rescue HttpParserError # try to tell the client they're bad
426 client.write_nonblock(Const::ERROR_400_RESPONSE) rescue nil
427 client.close rescue nil
429 client.write_nonblock(Const::ERROR_500_RESPONSE) rescue nil
430 client.close rescue nil
431 logger.error "Read error: #{e.inspect}"
432 logger.error e.backtrace.join("\n")
435 # gets rid of stuff the worker has no business keeping track of
436 # to free some resources and drops all sig handlers.
437 # traps for USR1, USR2, and HUP may be set in the @after_fork Proc
439 def init_worker_process(worker)
440 QUEUE_SIGS.each { |sig| trap(sig, 'IGNORE') }
441 trap(:CHLD, 'DEFAULT')
443 proc_name "worker[#{worker.nr}]"
446 WORKERS.values.each { |other| other.tempfile.close! rescue nil }
448 LISTENERS.each { |sock| sock.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }
449 worker.tempfile.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
450 @after_fork.call(self, worker) # can drop perms
451 @timeout /= 2.0 # halve it for select()
452 build_app! unless @config[:preload_app]
455 def reopen_worker_logs(worker_nr)
456 @logger.info "worker=#{worker_nr} reopening logs..."
457 Unicorn::Util.reopen_logs
458 @logger.info "worker=#{worker_nr} done reopening logs"
462 # runs inside each forked worker, this sits around and waits
463 # for connections and doesn't die until the parent dies (or is
464 # given a INT, QUIT, or TERM signal)
465 def worker_loop(worker)
466 master_pid = Process.ppid # slightly racy, but less memory usage
467 init_worker_process(worker)
468 nr = 0 # this becomes negative if we need to reopen logs
469 alive = worker.tempfile # tempfile is our lifeline to the master process
471 t = ti = Time.now.to_i
473 # closing anything we IO.select on will raise EBADF
474 trap(:USR1) { nr = -65536; SELF_PIPE.first.close rescue nil }
475 trap(:QUIT) { alive = nil; LISTENERS.each { |s| s.close rescue nil } }
476 [:TERM, :INT].each { |sig| trap(sig) { exit!(0) } } # instant shutdown
477 @logger.info "worker=#{worker.nr} ready"
480 nr < 0 and reopen_worker_logs(worker.nr)
483 # we're a goner in @timeout seconds anyways if alive.chmod
484 # breaks, so don't trap the exception. Using fchmod() since
485 # futimes() is not available in base Ruby and I very strongly
486 # prefer temporary files to be unlinked for security,
487 # performance and reliability reasons, so utime is out. No-op
488 # changes with chmod doesn't update ctime on all filesystems; so
489 # we change our counter each and every time (after process_client
490 # and before IO.select).
491 t == (ti = Time.now.to_i) or alive.chmod(t = ti)
495 process_client(sock.accept_nonblock)
497 t == (ti = Time.now.to_i) or alive.chmod(t = ti)
498 rescue Errno::EAGAIN, Errno::ECONNABORTED
503 # make the following bet: if we accepted clients this round,
504 # we're probably reasonably busy, so avoid calling select()
505 # and do a speculative accept_nonblock on every listener
506 # before we sleep again in select().
507 redo unless nr == 0 # (nr < 0) => reopen logs
509 master_pid == Process.ppid or return
510 t == (ti = Time.now.to_i) or alive.chmod(t = ti)
512 # timeout used so we can detect parent death:
513 ret = IO.select(LISTENERS, nil, SELF_PIPE, @timeout) or redo
522 logger.error "Unhandled listen loop exception #{e.inspect}."
523 logger.error e.backtrace.join("\n")
528 # delivers a signal to a worker and fails gracefully if the worker
529 # is no longer running.
530 def kill_worker(signal, pid)
532 Process.kill(signal, pid)
534 worker = WORKERS.delete(pid) and worker.tempfile.close rescue nil
538 # delivers a signal to each worker
539 def kill_each_worker(signal)
540 WORKERS.keys.each { |pid| kill_worker(signal, pid) }
543 # unlinks a PID file at given +path+ if it contains the current PID
544 # useful as an at_exit handler.
545 def unlink_pid_safe(path)
546 (File.read(path).to_i == $$ and File.unlink(path)) rescue nil
549 # returns a PID if a given path contains a non-stale PID file,
552 if File.exist?(path) && (pid = File.read(path).to_i) > 1
564 logger.info "reloading config_file=#{@config.config_file}"
565 @config[:listeners].replace(@init_listeners)
567 @config.commit!(self)
568 kill_each_worker(:QUIT)
569 logger.info "done reloading config_file=#{@config.config_file}"
571 logger.error "error reloading config_file=#{@config.config_file}: " \
572 "#{e.class} #{e.message}"
576 # returns an array of string names for the given listener array
577 def listener_names(listeners = LISTENERS)
578 listeners.map { |io| sock_name(io) }
582 @app = @app.call if @app.respond_to?(:arity) && @app.arity == 0
586 $0 = ([ File.basename(START_CTX[:zero]), tag ] +
587 START_CTX[:argv]).join(' ')
590 def redirect_io(io, path)
591 File.open(path, 'a') { |fp| io.reopen(fp) } if path
596 SELF_PIPE.each { |io| io.close rescue nil }
597 SELF_PIPE.replace(IO.pipe)
598 SELF_PIPE.each { |io| io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }