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 :Util, 'unicorn/util'
18 def run(app, options = {})
19 HttpServer.new(app, options).start.join
23 # This is the process manager of Unicorn. This manages worker
24 # processes which in turn handle the I/O and application process.
25 # Listener sockets are started in the master process and shared with
26 # forked worker children.
29 include ::Unicorn::SocketHelper
31 # prevents IO objects in here from being GC-ed
34 # all bound listener sockets
37 # This hash maps PIDs to Workers
40 # See: http://cr.yp.to/docs/selfpipe.html
43 # signal queue used for self-piping
46 # constant lookups are faster and we're single-threaded/non-reentrant
47 REQUEST = HttpRequest.new
49 # We populate this at startup so we can figure out how to reexecute
50 # and upgrade the currently running instance of Unicorn
52 :argv => ARGV.map { |arg| arg.dup },
53 # don't rely on Dir.pwd here since it's not symlink-aware, and
54 # symlink dirs are the default with Capistrano...
55 :cwd => `/bin/sh -c pwd`.chomp("\n"),
59 Worker = Struct.new(:nr, :tempfile) unless defined?(Worker)
61 # worker objects may be compared to just plain numbers
67 # Creates a working server on host:port (strange things happen if
68 # port isn't a Number). Use HttpServer::run to start the server and
69 # HttpServer.run.join to join the thread that's processing
70 # incoming requests on the socket.
71 def initialize(app, options = {})
75 @init_listeners = options[:listeners] ? options[:listeners].dup : []
76 @config = Configurator.new(options.merge(:use_defaults => true))
78 @config.commit!(self, :skip => [:listeners, :pid])
82 # Runs the thing. Returns self so you can run join on it
84 BasicSocket.do_not_reverse_lookup = true
86 # inherit sockets from parents, they need to be plain Socket objects
87 # before they become UNIXServer or TCPServer
88 inherited = ENV['UNICORN_FD'].to_s.split(/,/).map do |fd|
89 io = Socket.for_fd(fd.to_i)
90 set_server_sockopt(io, @listener_opts[sock_name(io)])
92 logger.info "inherited addr=#{sock_name(io)} fd=#{fd}"
96 config_listeners = @config[:listeners].dup
97 LISTENERS.replace(inherited)
99 # we start out with generic Socket objects that get cast to either
100 # TCPServer or UNIXServer objects; but since the Socket objects
101 # share the same OS-level file descriptor as the higher-level *Server
102 # objects; we need to prevent Socket objects from being garbage-collected
103 config_listeners -= listener_names
104 if config_listeners.empty? && LISTENERS.empty?
105 config_listeners << Unicorn::Const::DEFAULT_LISTEN
107 config_listeners.each { |addr| listen(addr) }
108 raise ArgumentError, "no listeners" if LISTENERS.empty?
109 self.pid = @config[:pid]
110 build_app! if @preload_app
111 maintain_worker_count
115 # replaces current listener set with +listeners+. This will
116 # close the socket if it will not exist in the new listener set
117 def listeners=(listeners)
118 cur_names, dead_names = [], []
119 listener_names.each do |name|
121 # mark unlinked sockets as dead so we can rebind them
122 (File.socket?(name) ? cur_names : dead_names) << name
127 set_names = listener_names(listeners)
128 dead_names += cur_names - set_names
131 LISTENERS.delete_if do |io|
132 if dead_names.include?(sock_name(io))
133 IO_PURGATORY.delete_if do |pio|
134 pio.fileno == io.fileno && (pio.close rescue nil).nil? # true
136 (io.close rescue nil).nil? # true
138 set_server_sockopt(io, @listener_opts[sock_name(io)])
143 (set_names - cur_names).each { |addr| listen(addr) }
146 def stdout_path=(path); redirect_io($stdout, path); end
147 def stderr_path=(path); redirect_io($stderr, path); end
150 REQUEST.logger = @logger = obj
153 # sets the path for the PID file of the master process
156 if x = valid_pid?(path)
157 return path if @pid && path == @pid && x == $$
158 raise ArgumentError, "Already running on PID:#{x} " \
159 "(or pid=#{path} is stale)"
162 unlink_pid_safe(@pid) if @pid
163 File.open(path, 'wb') { |fp| fp.syswrite("#$$\n") } if path
167 # add a given address to the +listeners+ set, idempotently
168 # Allows workers to add a private, per-process listener via the
169 # @after_fork hook. Very useful for debugging and testing.
170 def listen(address, opt = {}.merge(@listener_opts[address] || {}))
171 return if String === address && listener_names.include?(address)
173 if io = bind_listen(address, opt)
174 unless TCPServer === io || UNIXServer === io
178 logger.info "listening on addr=#{sock_name(io)} fd=#{io.fileno}"
181 logger.error "adding listener failed addr=#{address} (in use)"
182 raise Errno::EADDRINUSE, address
186 # monitors children and receives signals forever
187 # (or until a termination signal is sent). This handles signals
188 # one-at-a-time time and we'll happily drop signals in case somebody
189 # is signalling us too often.
191 # this pipe is used to wake us up from select(2) in #join when signals
192 # are trapped. See trap_deferred
196 QUEUE_SIGS.each { |sig| trap_deferred(sig) }
197 trap(:CHLD) { |sig_nr| awaken_master }
199 logger.info "master process ready" # test_exec.rb relies on this message
206 maintain_worker_count if respawn
208 when :QUIT # graceful shutdown
210 when :TERM, :INT # immediate shutdown
213 when :USR1 # rotate logs
214 logger.info "master reopening logs..."
215 Unicorn::Util.reopen_logs
216 logger.info "master done reopening logs"
217 kill_each_worker(:USR1)
218 when :USR2 # exec binary, stay alive in case something went wrong
221 if Process.ppid == 1 || Process.getpgrp != $$
223 logger.info "gracefully stopping all workers"
224 kill_each_worker(:QUIT)
226 logger.info "SIGWINCH ignored because we're not daemonized"
229 @worker_processes += 1
231 @worker_processes -= 1 if @worker_processes > 0
234 if @config.config_file
236 redo # immediate reaping since we may have QUIT workers
237 else # exec binary and exit if there's no config file
238 logger.info "config_file not present, reexecuting binary"
247 logger.error "Unhandled master loop exception #{e.inspect}."
248 logger.error e.backtrace.join("\n")
251 stop # gracefully shutdown all workers on our way out
252 logger.info "master complete"
253 unlink_pid_safe(@pid) if @pid
256 # Terminates all workers, but does not exit master process
257 def stop(graceful = true)
258 kill_each_worker(graceful ? :QUIT : :TERM)
265 (timeleft -= step) > 0 and next
266 kill_each_worker(:KILL)
274 # list of signals we care about and trap in master.
275 QUEUE_SIGS = [ :WINCH, :QUIT, :INT, :TERM, :USR1, :USR2, :HUP,
276 :TTIN, :TTOU ].freeze
278 # defer a signal for later processing in #join (master process)
279 def trap_deferred(signal)
280 trap(signal) do |sig_nr|
281 if SIG_QUEUE.size < 5
285 logger.error "ignoring SIG#{signal}, queue=#{SIG_QUEUE.inspect}"
290 # wait for a signal hander to wake us up and then consume the pipe
291 # Wake up every second anyways to run murder_lazy_workers
294 ready = IO.select([SELF_PIPE.first], nil, nil, 1) or return
295 ready.first && ready.first.first or return
296 loop { SELF_PIPE.first.read_nonblock(Const::CHUNK_SIZE) }
297 rescue Errno::EAGAIN, Errno::EINTR
303 SELF_PIPE.last.write_nonblock('.') # wakeup master process from select
304 rescue Errno::EAGAIN, Errno::EINTR
305 # pipe is full, master should wake up anyways
310 # reaps all unreaped workers
314 pid, status = Process.waitpid2(-1, Process::WNOHANG)
316 if @reexec_pid == pid
317 logger.error "reaped #{status.inspect} exec()-ed"
319 self.pid = @pid.chomp('.oldbin') if @pid
322 worker = WORKERS.delete(pid) and worker.tempfile.close rescue nil
323 logger.info "reaped #{status.inspect} " \
324 "worker=#{worker.nr rescue 'unknown'}"
331 # reexecutes the START_CTX with a new binary
335 Process.kill(0, @reexec_pid)
336 logger.error "reexec-ed child already running PID:#{@reexec_pid}"
344 old_pid = "#{@pid}.oldbin"
347 self.pid = old_pid # clear the path for a new pid file
349 logger.error "old PID:#{valid_pid?(old_pid)} running with " \
350 "existing pid=#{old_pid}, refusing rexec"
353 logger.error "error writing pid=#{old_pid} #{e.class} #{e.message}"
358 @reexec_pid = fork do
359 listener_fds = LISTENERS.map { |sock| sock.fileno }
360 ENV['UNICORN_FD'] = listener_fds.join(',')
361 Dir.chdir(START_CTX[:cwd])
362 cmd = [ START_CTX[:zero] ] + START_CTX[:argv]
364 # avoid leaking FDs we don't know about, but let before_exec
365 # unset FD_CLOEXEC, if anything else in the app eventually
366 # relies on FD inheritence.
367 (3..1024).each do |io|
368 next if listener_fds.include?(io)
369 io = IO.for_fd(io) rescue nil
372 io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
374 logger.info "executing #{cmd.inspect} (in #{Dir.pwd})"
375 @before_exec.call(self)
378 proc_name 'master (old)'
381 # forcibly terminate all workers that haven't checked in in @timeout
382 # seconds. The timeout is implemented using an unlinked tempfile
383 # shared between the parent process and each worker. The worker
384 # runs File#chmod to modify the ctime of the tempfile. If the ctime
385 # is stale for >@timeout seconds, then we'll kill the corresponding
387 def murder_lazy_workers
389 WORKERS.dup.each_pair do |pid, worker|
393 logger.warn "worker=#{worker.nr} PID:#{pid} stat error: #{e.inspect}"
394 kill_worker(:QUIT, pid)
397 stat.mode == 0100000 and next
398 (diff = (Time.now - stat.ctime)) <= @timeout and next
399 logger.error "worker=#{worker.nr} PID:#{pid} timeout " \
400 "(#{diff}s > #{@timeout}s), killing"
401 kill_worker(:KILL, pid) # take no prisoners for @timeout violations
405 def spawn_missing_workers
406 (0...@worker_processes).each do |worker_nr|
407 WORKERS.values.include?(worker_nr) and next
409 Dir.chdir(START_CTX[:cwd])
410 rescue Errno::ENOENT => err
411 logger.fatal "#{err.inspect} (#{START_CTX[:cwd]})"
412 SIG_QUEUE << :QUIT # forcibly emulate SIGQUIT
415 tempfile = Tempfile.new(nil) # as short as possible to save dir space
416 tempfile.unlink # don't allow other processes to find or see it
417 worker = Worker.new(worker_nr, tempfile)
418 @before_fork.call(self, worker)
419 pid = fork { worker_loop(worker) }
420 WORKERS[pid] = worker
424 def maintain_worker_count
425 (off = WORKERS.size - @worker_processes) == 0 and return
426 off < 0 and return spawn_missing_workers
427 WORKERS.dup.each_pair { |pid,w|
428 w.nr >= @worker_processes and kill_worker(:QUIT, pid) rescue nil
432 # once a client is accepted, it is processed in its entirety here
433 # in 3 easy steps: read request, call app, write app response
434 def process_client(app, client)
435 HttpResponse.write(client, app.call(REQUEST.read(client)))
436 # if we get any error, try to write something back to the client
437 # assuming we haven't closed the socket, but don't get hung up
438 # if the socket is already closed or broken. We'll always ensure
439 # the socket is closed at the end of this function
440 rescue EOFError,Errno::ECONNRESET,Errno::EPIPE,Errno::EINVAL,Errno::EBADF
441 client.write_nonblock(Const::ERROR_500_RESPONSE) rescue nil
442 client.close rescue nil
443 rescue HttpParserError # try to tell the client they're bad
444 client.write_nonblock(Const::ERROR_400_RESPONSE) rescue nil
445 client.close rescue nil
447 client.write_nonblock(Const::ERROR_500_RESPONSE) rescue nil
448 client.close rescue nil
449 logger.error "Read error: #{e.inspect}"
450 logger.error e.backtrace.join("\n")
453 # gets rid of stuff the worker has no business keeping track of
454 # to free some resources and drops all sig handlers.
455 # traps for USR1, USR2, and HUP may be set in the @after_fork Proc
457 def init_worker_process(worker)
458 QUEUE_SIGS.each { |sig| trap(sig, 'IGNORE') }
459 trap(:CHLD, 'DEFAULT')
461 proc_name "worker[#{worker.nr}]"
464 WORKERS.values.each { |other| other.tempfile.close! rescue nil }
466 LISTENERS.each { |sock| sock.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }
467 worker.tempfile.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
468 @after_fork.call(self, worker) # can drop perms
469 @timeout /= 2.0 # halve it for select()
470 HttpRequest::TEE.setup
471 build_app! unless @preload_app
474 def reopen_worker_logs(worker_nr)
475 @logger.info "worker=#{worker_nr} reopening logs..."
476 Unicorn::Util.reopen_logs
477 @logger.info "worker=#{worker_nr} done reopening logs"
481 # runs inside each forked worker, this sits around and waits
482 # for connections and doesn't die until the parent dies (or is
483 # given a INT, QUIT, or TERM signal)
484 def worker_loop(worker)
485 master_pid = Process.ppid # slightly racy, but less memory usage
486 init_worker_process(worker)
487 nr = 0 # this becomes negative if we need to reopen logs
488 alive = worker.tempfile # tempfile is our lifeline to the master process
492 # closing anything we IO.select on will raise EBADF
493 trap(:USR1) { nr = -65536; SELF_PIPE.first.close rescue nil }
494 trap(:QUIT) { alive = nil; LISTENERS.each { |s| s.close rescue nil } }
495 [:TERM, :INT].each { |sig| trap(sig) { exit!(0) } } # instant shutdown
496 @logger.info "worker=#{worker.nr} ready"
500 nr < 0 and reopen_worker_logs(worker.nr)
503 # we're a goner in @timeout seconds anyways if alive.chmod
504 # breaks, so don't trap the exception. Using fchmod() since
505 # futimes() is not available in base Ruby and I very strongly
506 # prefer temporary files to be unlinked for security,
507 # performance and reliability reasons, so utime is out. No-op
508 # changes with chmod doesn't update ctime on all filesystems; so
509 # we change our counter each and every time (after process_client
510 # and before IO.select).
511 t == (ti = Time.now.to_i) or alive.chmod(t = ti)
515 process_client(app, sock.accept_nonblock)
517 t == (ti = Time.now.to_i) or alive.chmod(t = ti)
518 rescue Errno::EAGAIN, Errno::ECONNABORTED
523 # make the following bet: if we accepted clients this round,
524 # we're probably reasonably busy, so avoid calling select()
525 # and do a speculative accept_nonblock on every listener
526 # before we sleep again in select().
527 redo unless nr == 0 # (nr < 0) => reopen logs
529 master_pid == Process.ppid or return
532 # timeout used so we can detect parent death:
533 ret = IO.select(LISTENERS, nil, SELF_PIPE, @timeout) or redo
542 logger.error "Unhandled listen loop exception #{e.inspect}."
543 logger.error e.backtrace.join("\n")
548 # delivers a signal to a worker and fails gracefully if the worker
549 # is no longer running.
550 def kill_worker(signal, pid)
552 Process.kill(signal, pid)
554 worker = WORKERS.delete(pid) and worker.tempfile.close rescue nil
558 # delivers a signal to each worker
559 def kill_each_worker(signal)
560 WORKERS.keys.each { |pid| kill_worker(signal, pid) }
563 # unlinks a PID file at given +path+ if it contains the current PID
564 # useful as an at_exit handler.
565 def unlink_pid_safe(path)
566 (File.read(path).to_i == $$ and File.unlink(path)) rescue nil
569 # returns a PID if a given path contains a non-stale PID file,
572 if File.exist?(path) && (pid = File.read(path).to_i) > 1
584 logger.info "reloading config_file=#{@config.config_file}"
585 @config[:listeners].replace(@init_listeners)
587 @config.commit!(self)
588 kill_each_worker(:QUIT)
589 Unicorn::Util.reopen_logs
591 build_app! if @preload_app
592 logger.info "done reloading config_file=#{@config.config_file}"
594 logger.error "error reloading config_file=#{@config.config_file}: " \
595 "#{e.class} #{e.message}"
599 # returns an array of string names for the given listener array
600 def listener_names(listeners = LISTENERS)
601 listeners.map { |io| sock_name(io) }
605 if @app.respond_to?(:arity) && @app.arity == 0
606 if defined?(Gem) && Gem.respond_to?(:refresh)
607 logger.info "Refreshing Gem list"
615 $0 = ([ File.basename(START_CTX[:zero]), tag ] +
616 START_CTX[:argv]).join(' ')
619 def redirect_io(io, path)
620 File.open(path, 'a') { |fp| io.reopen(fp) } if path
625 SELF_PIPE.each { |io| io.close rescue nil }
626 SELF_PIPE.replace(IO.pipe)
627 SELF_PIPE.each { |io| io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }