3 require 'unicorn/socket_helper'
6 # Unicorn module containing all of the classes (include C extensions) for running
7 # a Unicorn web server. It contains a minimalist HTTP server with just enough
8 # functionality to service web application requests fast as possible.
10 autoload :Const, 'unicorn/const'
11 autoload :HttpRequest, 'unicorn/http_request'
12 autoload :HttpResponse, 'unicorn/http_response'
13 autoload :Configurator, 'unicorn/configurator'
14 autoload :TeeInput, 'unicorn/tee_input'
15 autoload :ChunkedReader, 'unicorn/chunked_reader'
16 autoload :TrailerParser, 'unicorn/trailer_parser'
17 autoload :Util, 'unicorn/util'
19 Z = '' # the stock empty string we use everywhere...
20 Z.force_encoding(Encoding::BINARY) if Z.respond_to?(:force_encoding)
24 def run(app, options = {})
25 HttpServer.new(app, options).start.join
29 # This is the process manager of Unicorn. This manages worker
30 # processes which in turn handle the I/O and application process.
31 # Listener sockets are started in the master process and shared with
32 # forked worker children.
35 include ::Unicorn::SocketHelper
37 # prevents IO objects in here from being GC-ed
40 # all bound listener sockets
43 # This hash maps PIDs to Workers
46 # See: http://cr.yp.to/docs/selfpipe.html
49 # signal queue used for self-piping
52 # constant lookups are faster and we're single-threaded/non-reentrant
53 REQUEST = HttpRequest.new
55 # We populate this at startup so we can figure out how to reexecute
56 # and upgrade the currently running instance of Unicorn
58 :argv => ARGV.map { |arg| arg.dup },
59 # don't rely on Dir.pwd here since it's not symlink-aware, and
60 # symlink dirs are the default with Capistrano...
61 :cwd => `/bin/sh -c pwd`.chomp("\n"),
65 Worker = Struct.new(:nr, :tempfile) unless defined?(Worker)
67 # worker objects may be compared to just plain numbers
73 # Creates a working server on host:port (strange things happen if
74 # port isn't a Number). Use HttpServer::run to start the server and
75 # HttpServer.run.join to join the thread that's processing
76 # incoming requests on the socket.
77 def initialize(app, options = {})
81 @init_listeners = options[:listeners] ? options[:listeners].dup : []
82 @config = Configurator.new(options.merge(:use_defaults => true))
84 @config.commit!(self, :skip => [:listeners, :pid])
88 # Runs the thing. Returns self so you can run join on it
90 BasicSocket.do_not_reverse_lookup = true
92 # inherit sockets from parents, they need to be plain Socket objects
93 # before they become UNIXServer or TCPServer
94 inherited = ENV['UNICORN_FD'].to_s.split(/,/).map do |fd|
95 io = Socket.for_fd(fd.to_i)
96 set_server_sockopt(io, @listener_opts[sock_name(io)])
98 logger.info "inherited addr=#{sock_name(io)} fd=#{fd}"
102 config_listeners = @config[:listeners].dup
103 LISTENERS.replace(inherited)
105 # we start out with generic Socket objects that get cast to either
106 # TCPServer or UNIXServer objects; but since the Socket objects
107 # share the same OS-level file descriptor as the higher-level *Server
108 # objects; we need to prevent Socket objects from being garbage-collected
109 config_listeners -= listener_names
110 if config_listeners.empty? && LISTENERS.empty?
111 config_listeners << Unicorn::Const::DEFAULT_LISTEN
113 config_listeners.each { |addr| listen(addr) }
114 raise ArgumentError, "no listeners" if LISTENERS.empty?
115 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
155 REQUEST.logger = @logger = obj
158 # sets the path for the PID file of the master process
161 if x = valid_pid?(path)
162 return path if @pid && path == @pid && x == $$
163 raise ArgumentError, "Already running on PID:#{x} " \
164 "(or pid=#{path} is stale)"
167 unlink_pid_safe(@pid) if @pid
168 File.open(path, 'wb') { |fp| fp.syswrite("#$$\n") } if path
172 # add a given address to the +listeners+ set, idempotently
173 # Allows workers to add a private, per-process listener via the
174 # @after_fork hook. Very useful for debugging and testing.
175 def listen(address, opt = {}.merge(@listener_opts[address] || {}))
176 return if String === address && listener_names.include?(address)
178 delay, tries = 0.5, 5
180 io = bind_listen(address, opt)
181 unless TCPServer === io || UNIXServer === io
185 logger.info "listening on addr=#{sock_name(io)} fd=#{io.fileno}"
188 rescue Errno::EADDRINUSE => err
189 logger.error "adding listener failed addr=#{address} (in use)"
190 raise err if tries == 0
192 logger.error "retrying in #{delay} seconds (#{tries} tries left)"
198 # monitors children and receives signals forever
199 # (or until a termination signal is sent). This handles signals
200 # one-at-a-time time and we'll happily drop signals in case somebody
201 # is signalling us too often.
203 # this pipe is used to wake us up from select(2) in #join when signals
204 # are trapped. See trap_deferred
208 QUEUE_SIGS.each { |sig| trap_deferred(sig) }
209 trap(:CHLD) { |sig_nr| awaken_master }
211 logger.info "master process ready" # test_exec.rb relies on this message
218 maintain_worker_count if respawn
220 when :QUIT # graceful shutdown
222 when :TERM, :INT # immediate shutdown
225 when :USR1 # rotate logs
226 logger.info "master reopening logs..."
227 Unicorn::Util.reopen_logs
228 logger.info "master done reopening logs"
229 kill_each_worker(:USR1)
230 when :USR2 # exec binary, stay alive in case something went wrong
233 if Process.ppid == 1 || Process.getpgrp != $$
235 logger.info "gracefully stopping all workers"
236 kill_each_worker(:QUIT)
238 logger.info "SIGWINCH ignored because we're not daemonized"
241 @worker_processes += 1
243 @worker_processes -= 1 if @worker_processes > 0
246 if @config.config_file
248 redo # immediate reaping since we may have QUIT workers
249 else # exec binary and exit if there's no config file
250 logger.info "config_file not present, reexecuting binary"
259 logger.error "Unhandled master loop exception #{e.inspect}."
260 logger.error e.backtrace.join("\n")
263 stop # gracefully shutdown all workers on our way out
264 logger.info "master complete"
265 unlink_pid_safe(@pid) if @pid
268 # Terminates all workers, but does not exit master process
269 def stop(graceful = true)
271 kill_each_worker(graceful ? :QUIT : :TERM)
278 (timeleft -= step) > 0 and next
279 kill_each_worker(:KILL)
285 # list of signals we care about and trap in master.
286 QUEUE_SIGS = [ :WINCH, :QUIT, :INT, :TERM, :USR1, :USR2, :HUP,
287 :TTIN, :TTOU ].freeze
289 # defer a signal for later processing in #join (master process)
290 def trap_deferred(signal)
291 trap(signal) do |sig_nr|
292 if SIG_QUEUE.size < 5
296 logger.error "ignoring SIG#{signal}, queue=#{SIG_QUEUE.inspect}"
301 # wait for a signal hander to wake us up and then consume the pipe
302 # Wake up every second anyways to run murder_lazy_workers
305 ready = IO.select([SELF_PIPE.first], nil, nil, 1) or return
306 ready.first && ready.first.first or return
307 loop { SELF_PIPE.first.read_nonblock(Const::CHUNK_SIZE) }
308 rescue Errno::EAGAIN, Errno::EINTR
314 SELF_PIPE.last.write_nonblock('.') # wakeup master process from select
315 rescue Errno::EAGAIN, Errno::EINTR
316 # pipe is full, master should wake up anyways
321 # reaps all unreaped workers
325 pid, status = Process.waitpid2(-1, Process::WNOHANG)
327 if @reexec_pid == pid
328 logger.error "reaped #{status.inspect} exec()-ed"
330 self.pid = @pid.chomp('.oldbin') if @pid
333 worker = WORKERS.delete(pid) and worker.tempfile.close rescue nil
334 logger.info "reaped #{status.inspect} " \
335 "worker=#{worker.nr rescue 'unknown'}"
342 # reexecutes the START_CTX with a new binary
346 Process.kill(0, @reexec_pid)
347 logger.error "reexec-ed child already running PID:#{@reexec_pid}"
355 old_pid = "#{@pid}.oldbin"
358 self.pid = old_pid # clear the path for a new pid file
360 logger.error "old PID:#{valid_pid?(old_pid)} running with " \
361 "existing pid=#{old_pid}, refusing rexec"
364 logger.error "error writing pid=#{old_pid} #{e.class} #{e.message}"
369 @reexec_pid = fork do
370 listener_fds = LISTENERS.map { |sock| sock.fileno }
371 ENV['UNICORN_FD'] = listener_fds.join(',')
372 Dir.chdir(START_CTX[:cwd])
373 cmd = [ START_CTX[:zero] ] + START_CTX[:argv]
375 # avoid leaking FDs we don't know about, but let before_exec
376 # unset FD_CLOEXEC, if anything else in the app eventually
377 # relies on FD inheritence.
378 (3..1024).each do |io|
379 next if listener_fds.include?(io)
380 io = IO.for_fd(io) rescue nil
383 io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
385 logger.info "executing #{cmd.inspect} (in #{Dir.pwd})"
386 @before_exec.call(self)
389 proc_name 'master (old)'
392 # forcibly terminate all workers that haven't checked in in @timeout
393 # seconds. The timeout is implemented using an unlinked tempfile
394 # shared between the parent process and each worker. The worker
395 # runs File#chmod to modify the ctime of the tempfile. If the ctime
396 # is stale for >@timeout seconds, then we'll kill the corresponding
398 def murder_lazy_workers
400 WORKERS.dup.each_pair do |pid, worker|
404 logger.warn "worker=#{worker.nr} PID:#{pid} stat error: #{e.inspect}"
405 kill_worker(:QUIT, pid)
408 stat.mode == 0100000 and next
409 (diff = (Time.now - stat.ctime)) <= @timeout and next
410 logger.error "worker=#{worker.nr} PID:#{pid} timeout " \
411 "(#{diff}s > #{@timeout}s), killing"
412 kill_worker(:KILL, pid) # take no prisoners for @timeout violations
416 def spawn_missing_workers
417 (0...@worker_processes).each do |worker_nr|
418 WORKERS.values.include?(worker_nr) and next
420 Dir.chdir(START_CTX[:cwd])
421 rescue Errno::ENOENT => err
422 logger.fatal "#{err.inspect} (#{START_CTX[:cwd]})"
423 SIG_QUEUE << :QUIT # forcibly emulate SIGQUIT
426 tempfile = Tempfile.new(nil) # as short as possible to save dir space
427 tempfile.unlink # don't allow other processes to find or see it
428 worker = Worker.new(worker_nr, tempfile)
429 @before_fork.call(self, worker)
430 pid = fork { worker_loop(worker) }
431 WORKERS[pid] = 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 { |pid,w|
439 w.nr >= @worker_processes and kill_worker(:QUIT, pid) 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(app, client)
446 response = app.call(env = REQUEST.read(client))
448 if 100 == response.first.to_i
449 client.write(Const::EXPECT_100_RESPONSE)
450 env.delete(Const::HTTP_EXPECT)
451 response = app.call(env)
454 HttpResponse.write(client, response)
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, 'IGNORE') }
478 trap(:CHLD, 'DEFAULT')
480 proc_name "worker[#{worker.nr}]"
483 WORKERS.values.each { |other| other.tempfile.close! rescue nil }
485 LISTENERS.each { |sock| sock.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }
486 worker.tempfile.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
487 @after_fork.call(self, worker) # can drop perms
488 @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)
503 master_pid = Process.ppid # slightly racy, but less memory usage
504 init_worker_process(worker)
505 nr = 0 # this becomes negative if we need to reopen logs
506 alive = worker.tempfile # tempfile 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"
518 nr < 0 and reopen_worker_logs(worker.nr)
521 # we're a goner in @timeout seconds anyways if alive.chmod
522 # breaks, so don't trap the exception. Using fchmod() since
523 # futimes() is not available in base Ruby and I very strongly
524 # prefer temporary files to be unlinked for security,
525 # performance and reliability reasons, so utime is out. No-op
526 # changes with chmod doesn't update ctime on all filesystems; so
527 # we change our counter each and every time (after process_client
528 # and before IO.select).
529 t == (ti = Time.now.to_i) or alive.chmod(t = ti)
533 process_client(app, sock.accept_nonblock)
535 t == (ti = Time.now.to_i) or alive.chmod(t = ti)
536 rescue Errno::EAGAIN, Errno::ECONNABORTED
541 # make the following bet: if we accepted clients this round,
542 # we're probably reasonably busy, so avoid calling select()
543 # and do a speculative accept_nonblock on every listener
544 # before we sleep again in select().
545 redo unless nr == 0 # (nr < 0) => reopen logs
547 master_pid == Process.ppid or return
550 # timeout used so we can detect parent death:
551 ret = IO.select(LISTENERS, nil, SELF_PIPE, @timeout) or redo
560 logger.error "Unhandled listen loop exception #{e.inspect}."
561 logger.error e.backtrace.join("\n")
566 # delivers a signal to a worker and fails gracefully if the worker
567 # is no longer running.
568 def kill_worker(signal, pid)
570 Process.kill(signal, pid)
572 worker = WORKERS.delete(pid) and worker.tempfile.close rescue nil
576 # delivers a signal to each worker
577 def kill_each_worker(signal)
578 WORKERS.keys.each { |pid| kill_worker(signal, pid) }
581 # unlinks a PID file at given +path+ if it contains the current PID
582 # useful as an at_exit handler.
583 def unlink_pid_safe(path)
584 (File.read(path).to_i == $$ and File.unlink(path)) rescue nil
587 # returns a PID if a given path contains a non-stale PID file,
590 if File.exist?(path) && (pid = File.read(path).to_i) > 1
602 logger.info "reloading config_file=#{@config.config_file}"
603 @config[:listeners].replace(@init_listeners)
605 @config.commit!(self)
606 kill_each_worker(:QUIT)
607 Unicorn::Util.reopen_logs
609 build_app! if @preload_app
610 logger.info "done reloading config_file=#{@config.config_file}"
612 logger.error "error reloading config_file=#{@config.config_file}: " \
613 "#{e.class} #{e.message}"
617 # returns an array of string names for the given listener array
618 def listener_names(listeners = LISTENERS)
619 listeners.map { |io| sock_name(io) }
623 if @app.respond_to?(:arity) && @app.arity == 0
624 if defined?(Gem) && Gem.respond_to?(:refresh)
625 logger.info "Refreshing Gem list"
633 $0 = ([ File.basename(START_CTX[:zero]), tag ] +
634 START_CTX[:argv]).join(' ')
637 def redirect_io(io, path)
638 File.open(path, 'a') { |fp| io.reopen(fp) } if path
643 SELF_PIPE.each { |io| io.close rescue nil }
644 SELF_PIPE.replace(IO.pipe)
645 SELF_PIPE.each { |io| io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) }