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Diffstat (limited to 'lib/unicorn/http_server.rb')
-rw-r--r-- | lib/unicorn/http_server.rb | 700 |
1 files changed, 700 insertions, 0 deletions
diff --git a/lib/unicorn/http_server.rb b/lib/unicorn/http_server.rb new file mode 100644 index 0000000..d6fc0bd --- /dev/null +++ b/lib/unicorn/http_server.rb @@ -0,0 +1,700 @@ +# -*- encoding: binary -*- + +# This is the process manager of Unicorn. This manages worker +# processes which in turn handle the I/O and application process. +# Listener sockets are started in the master process and shared with +# forked worker children. +class Unicorn::HttpServer + attr_accessor :app, :request, :timeout, :worker_processes, + :before_fork, :after_fork, :before_exec, + :logger, :pid, :listener_opts, :preload_app, + :reexec_pid, :orig_app, :init_listeners, + :master_pid, :config, :ready_pipe, :user + + # :stopdoc: + include Unicorn::SocketHelper + include Unicorn::HttpResponse + + # backwards compatibility with 1.x + Worker = Unicorn::Worker + + # prevents IO objects in here from being GC-ed + IO_PURGATORY = [] + + # all bound listener sockets + LISTENERS = [] + + # This hash maps PIDs to Workers + WORKERS = {} + + # We use SELF_PIPE differently in the master and worker processes: + # + # * The master process never closes or reinitializes this once + # initialized. Signal handlers in the master process will write to + # it to wake up the master from IO.select in exactly the same manner + # djb describes in http://cr.yp.to/docs/selfpipe.html + # + # * The workers immediately close the pipe they inherit from the + # master and replace it with a new pipe after forking. This new + # pipe is also used to wakeup from IO.select from inside (worker) + # signal handlers. However, workers *close* the pipe descriptors in + # the signal handlers to raise EBADF in IO.select instead of writing + # like we do in the master. We cannot easily use the reader set for + # IO.select because LISTENERS is already that set, and it's extra + # work (and cycles) to distinguish the pipe FD from the reader set + # once IO.select returns. So we're lazy and just close the pipe when + # a (rare) signal arrives in the worker and reinitialize the pipe later. + SELF_PIPE = [] + + # signal queue used for self-piping + SIG_QUEUE = [] + + # We populate this at startup so we can figure out how to reexecute + # and upgrade the currently running instance of Unicorn + # This Hash is considered a stable interface and changing its contents + # will allow you to switch between different installations of Unicorn + # or even different installations of the same applications without + # downtime. Keys of this constant Hash are described as follows: + # + # * 0 - the path to the unicorn/unicorn_rails executable + # * :argv - a deep copy of the ARGV array the executable originally saw + # * :cwd - the working directory of the application, this is where + # you originally started Unicorn. + # + # To change your unicorn executable to a different path without downtime, + # you can set the following in your Unicorn config file, HUP and then + # continue with the traditional USR2 + QUIT upgrade steps: + # + # Unicorn::HttpServer::START_CTX[0] = "/home/bofh/1.9.2/bin/unicorn" + START_CTX = { + :argv => ARGV.map { |arg| arg.dup }, + :cwd => lambda { + # favor ENV['PWD'] since it is (usually) symlink aware for + # Capistrano and like systems + begin + a = File.stat(pwd = ENV['PWD']) + b = File.stat(Dir.pwd) + a.ino == b.ino && a.dev == b.dev ? pwd : Dir.pwd + rescue + Dir.pwd + end + }.call, + 0 => $0.dup, + } + # :startdoc: + + # Creates a working server on host:port (strange things happen if + # port isn't a Number). Use HttpServer::run to start the server and + # HttpServer.run.join to join the thread that's processing + # incoming requests on the socket. + def initialize(app, options = {}) + @app = app + @request = Unicorn::HttpRequest.new + self.reexec_pid = 0 + options = options.dup + self.ready_pipe = options.delete(:ready_pipe) + self.init_listeners = options[:listeners] ? options[:listeners].dup : [] + options[:use_defaults] = true + self.config = Unicorn::Configurator.new(options) + self.listener_opts = {} + + # we try inheriting listeners first, so we bind them later. + # we don't write the pid file until we've bound listeners in case + # unicorn was started twice by mistake. Even though our #pid= method + # checks for stale/existing pid files, race conditions are still + # possible (and difficult/non-portable to avoid) and can be likely + # to clobber the pid if the second start was in quick succession + # after the first, so we rely on the listener binding to fail in + # that case. Some tests (in and outside of this source tree) and + # monitoring tools may also rely on pid files existing before we + # attempt to connect to the listener(s) + config.commit!(self, :skip => [:listeners, :pid]) + self.orig_app = app + end + + # Runs the thing. Returns self so you can run join on it + def start + BasicSocket.do_not_reverse_lookup = true + + # inherit sockets from parents, they need to be plain Socket objects + # before they become Kgio::UNIXServer or Kgio::TCPServer + inherited = ENV['UNICORN_FD'].to_s.split(/,/).map do |fd| + io = Socket.for_fd(fd.to_i) + set_server_sockopt(io, listener_opts[sock_name(io)]) + IO_PURGATORY << io + logger.info "inherited addr=#{sock_name(io)} fd=#{fd}" + server_cast(io) + end + + config_listeners = config[:listeners].dup + LISTENERS.replace(inherited) + + # we start out with generic Socket objects that get cast to either + # Kgio::TCPServer or Kgio::UNIXServer objects; but since the Socket + # objects share the same OS-level file descriptor as the higher-level + # *Server objects; we need to prevent Socket objects from being + # garbage-collected + config_listeners -= listener_names + if config_listeners.empty? && LISTENERS.empty? + config_listeners << Unicorn::Const::DEFAULT_LISTEN + init_listeners << Unicorn::Const::DEFAULT_LISTEN + START_CTX[:argv] << "-l#{Unicorn::Const::DEFAULT_LISTEN}" + end + config_listeners.each { |addr| listen(addr) } + raise ArgumentError, "no listeners" if LISTENERS.empty? + + # this pipe is used to wake us up from select(2) in #join when signals + # are trapped. See trap_deferred. + init_self_pipe! + + # setup signal handlers before writing pid file in case people get + # trigger happy and send signals as soon as the pid file exists. + # Note that signals don't actually get handled until the #join method + QUEUE_SIGS.each { |sig| trap_deferred(sig) } + trap(:CHLD) { |_| awaken_master } + self.pid = config[:pid] + + self.master_pid = $$ + build_app! if preload_app + maintain_worker_count + self + end + + # replaces current listener set with +listeners+. This will + # close the socket if it will not exist in the new listener set + def listeners=(listeners) + cur_names, dead_names = [], [] + listener_names.each do |name| + if ?/ == name[0] + # mark unlinked sockets as dead so we can rebind them + (File.socket?(name) ? cur_names : dead_names) << name + else + cur_names << name + end + end + set_names = listener_names(listeners) + dead_names.concat(cur_names - set_names).uniq! + + LISTENERS.delete_if do |io| + if dead_names.include?(sock_name(io)) + IO_PURGATORY.delete_if do |pio| + pio.fileno == io.fileno && (pio.close rescue nil).nil? # true + end + (io.close rescue nil).nil? # true + else + set_server_sockopt(io, listener_opts[sock_name(io)]) + false + end + end + + (set_names - cur_names).each { |addr| listen(addr) } + end + + def stdout_path=(path); redirect_io($stdout, path); end + def stderr_path=(path); redirect_io($stderr, path); end + + def logger=(obj) + Unicorn::HttpRequest::DEFAULTS["rack.logger"] = @logger = obj + end + + # sets the path for the PID file of the master process + def pid=(path) + if path + if x = valid_pid?(path) + return path if pid && path == pid && x == $$ + if x == reexec_pid && pid =~ /\.oldbin\z/ + logger.warn("will not set pid=#{path} while reexec-ed "\ + "child is running PID:#{x}") + return + end + raise ArgumentError, "Already running on PID:#{x} " \ + "(or pid=#{path} is stale)" + end + end + unlink_pid_safe(pid) if pid + + if path + fp = begin + tmp = "#{File.dirname(path)}/#{rand}.#$$" + File.open(tmp, File::RDWR|File::CREAT|File::EXCL, 0644) + rescue Errno::EEXIST + retry + end + fp.syswrite("#$$\n") + File.rename(fp.path, path) + fp.close + end + @pid = path + end + + # add a given address to the +listeners+ set, idempotently + # Allows workers to add a private, per-process listener via the + # after_fork hook. Very useful for debugging and testing. + # +:tries+ may be specified as an option for the number of times + # to retry, and +:delay+ may be specified as the time in seconds + # to delay between retries. + # A negative value for +:tries+ indicates the listen will be + # retried indefinitely, this is useful when workers belonging to + # different masters are spawned during a transparent upgrade. + def listen(address, opt = {}.merge(listener_opts[address] || {})) + address = config.expand_addr(address) + return if String === address && listener_names.include?(address) + + delay = opt[:delay] || 0.5 + tries = opt[:tries] || 5 + begin + io = bind_listen(address, opt) + unless Kgio::TCPServer === io || Kgio::UNIXServer === io + IO_PURGATORY << io + io = server_cast(io) + end + logger.info "listening on addr=#{sock_name(io)} fd=#{io.fileno}" + LISTENERS << io + io + rescue Errno::EADDRINUSE => err + logger.error "adding listener failed addr=#{address} (in use)" + raise err if tries == 0 + tries -= 1 + logger.error "retrying in #{delay} seconds " \ + "(#{tries < 0 ? 'infinite' : tries} tries left)" + sleep(delay) + retry + rescue => err + logger.fatal "error adding listener addr=#{address}" + raise err + end + end + + # monitors children and receives signals forever + # (or until a termination signal is sent). This handles signals + # one-at-a-time time and we'll happily drop signals in case somebody + # is signalling us too often. + def join + respawn = true + last_check = Time.now + + proc_name 'master' + logger.info "master process ready" # test_exec.rb relies on this message + if ready_pipe + ready_pipe.syswrite($$.to_s) + ready_pipe.close rescue nil + self.ready_pipe = nil + end + begin + reap_all_workers + case SIG_QUEUE.shift + when nil + # avoid murdering workers after our master process (or the + # machine) comes out of suspend/hibernation + if (last_check + timeout) >= (last_check = Time.now) + murder_lazy_workers + else + # wait for workers to wakeup on suspend + master_sleep(timeout/2.0 + 1) + end + maintain_worker_count if respawn + master_sleep(1) + when :QUIT # graceful shutdown + break + when :TERM, :INT # immediate shutdown + stop(false) + break + when :USR1 # rotate logs + logger.info "master reopening logs..." + Unicorn::Util.reopen_logs + logger.info "master done reopening logs" + kill_each_worker(:USR1) + when :USR2 # exec binary, stay alive in case something went wrong + reexec + when :WINCH + if Process.ppid == 1 || Process.getpgrp != $$ + respawn = false + logger.info "gracefully stopping all workers" + kill_each_worker(:QUIT) + self.worker_processes = 0 + else + logger.info "SIGWINCH ignored because we're not daemonized" + end + when :TTIN + respawn = true + self.worker_processes += 1 + when :TTOU + self.worker_processes -= 1 if self.worker_processes > 0 + when :HUP + respawn = true + if config.config_file + load_config! + else # exec binary and exit if there's no config file + logger.info "config_file not present, reexecuting binary" + reexec + end + end + rescue Errno::EINTR + rescue => e + logger.error "Unhandled master loop exception #{e.inspect}." + logger.error e.backtrace.join("\n") + end while true + stop # gracefully shutdown all workers on our way out + logger.info "master complete" + unlink_pid_safe(pid) if pid + end + + # Terminates all workers, but does not exit master process + def stop(graceful = true) + self.listeners = [] + limit = Time.now + timeout + until WORKERS.empty? || Time.now > limit + kill_each_worker(graceful ? :QUIT : :TERM) + sleep(0.1) + reap_all_workers + end + kill_each_worker(:KILL) + end + + private + + # list of signals we care about and trap in master. + QUEUE_SIGS = [ :WINCH, :QUIT, :INT, :TERM, :USR1, :USR2, :HUP, + :TTIN, :TTOU ] + + # defer a signal for later processing in #join (master process) + def trap_deferred(signal) + trap(signal) do |sig_nr| + if SIG_QUEUE.size < 5 + SIG_QUEUE << signal + awaken_master + else + logger.error "ignoring SIG#{signal}, queue=#{SIG_QUEUE.inspect}" + end + end + end + + # wait for a signal hander to wake us up and then consume the pipe + # Wake up every second anyways to run murder_lazy_workers + def master_sleep(sec) + IO.select([ SELF_PIPE[0] ], nil, nil, sec) or return + SELF_PIPE[0].kgio_tryread(11) + end + + def awaken_master + SELF_PIPE[1].kgio_trywrite('.') # wakeup master process from select + end + + # reaps all unreaped workers + def reap_all_workers + begin + wpid, status = Process.waitpid2(-1, Process::WNOHANG) + wpid or return + if reexec_pid == wpid + logger.error "reaped #{status.inspect} exec()-ed" + self.reexec_pid = 0 + self.pid = pid.chomp('.oldbin') if pid + proc_name 'master' + else + worker = WORKERS.delete(wpid) and worker.tmp.close rescue nil + m = "reaped #{status.inspect} worker=#{worker.nr rescue 'unknown'}" + status.success? ? logger.info(m) : logger.error(m) + end + rescue Errno::ECHILD + break + end while true + end + + # reexecutes the START_CTX with a new binary + def reexec + if reexec_pid > 0 + begin + Process.kill(0, reexec_pid) + logger.error "reexec-ed child already running PID:#{reexec_pid}" + return + rescue Errno::ESRCH + self.reexec_pid = 0 + end + end + + if pid + old_pid = "#{pid}.oldbin" + prev_pid = pid.dup + begin + self.pid = old_pid # clear the path for a new pid file + rescue ArgumentError + logger.error "old PID:#{valid_pid?(old_pid)} running with " \ + "existing pid=#{old_pid}, refusing rexec" + return + rescue => e + logger.error "error writing pid=#{old_pid} #{e.class} #{e.message}" + return + end + end + + self.reexec_pid = fork do + listener_fds = LISTENERS.map { |sock| sock.fileno } + ENV['UNICORN_FD'] = listener_fds.join(',') + Dir.chdir(START_CTX[:cwd]) + cmd = [ START_CTX[0] ].concat(START_CTX[:argv]) + + # avoid leaking FDs we don't know about, but let before_exec + # unset FD_CLOEXEC, if anything else in the app eventually + # relies on FD inheritence. + (3..1024).each do |io| + next if listener_fds.include?(io) + io = IO.for_fd(io) rescue next + IO_PURGATORY << io + io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) + end + logger.info "executing #{cmd.inspect} (in #{Dir.pwd})" + before_exec.call(self) + exec(*cmd) + end + proc_name 'master (old)' + end + + # forcibly terminate all workers that haven't checked in in timeout + # seconds. The timeout is implemented using an unlinked File + # shared between the parent process and each worker. The worker + # runs File#chmod to modify the ctime of the File. If the ctime + # is stale for >timeout seconds, then we'll kill the corresponding + # worker. + def murder_lazy_workers + WORKERS.dup.each_pair do |wpid, worker| + stat = worker.tmp.stat + # skip workers that disable fchmod or have never fchmod-ed + stat.mode == 0100600 and next + (diff = (Time.now - stat.ctime)) <= timeout and next + logger.error "worker=#{worker.nr} PID:#{wpid} timeout " \ + "(#{diff}s > #{timeout}s), killing" + kill_worker(:KILL, wpid) # take no prisoners for timeout violations + end + end + + def spawn_missing_workers + (0...worker_processes).each do |worker_nr| + WORKERS.values.include?(worker_nr) and next + worker = Worker.new(worker_nr, Unicorn::TmpIO.new) + before_fork.call(self, worker) + WORKERS[fork { + ready_pipe.close if ready_pipe + self.ready_pipe = nil + worker_loop(worker) + }] = worker + end + end + + def maintain_worker_count + (off = WORKERS.size - worker_processes) == 0 and return + off < 0 and return spawn_missing_workers + WORKERS.dup.each_pair { |wpid,w| + w.nr >= worker_processes and kill_worker(:QUIT, wpid) rescue nil + } + end + + # if we get any error, try to write something back to the client + # assuming we haven't closed the socket, but don't get hung up + # if the socket is already closed or broken. We'll always ensure + # the socket is closed at the end of this function + def handle_error(client, e) + msg = case e + when EOFError,Errno::ECONNRESET,Errno::EPIPE,Errno::EINVAL,Errno::EBADF + Unicorn::Const::ERROR_500_RESPONSE + when HttpParserError # try to tell the client they're bad + Unicorn::Const::ERROR_400_RESPONSE + else + logger.error "Read error: #{e.inspect}" + logger.error e.backtrace.join("\n") + Unicorn::Const::ERROR_500_RESPONSE + end + client.kgio_trywrite(msg) + client.close + rescue + nil + end + + # once a client is accepted, it is processed in its entirety here + # in 3 easy steps: read request, call app, write app response + def process_client(client) + r = @app.call(env = @request.read(client)) + + if 100 == r[0].to_i + client.write(Unicorn::Const::EXPECT_100_RESPONSE) + env.delete(Unicorn::Const::HTTP_EXPECT) + r = @app.call(env) + end + # r may be frozen or const, so don't modify it + @request.response_headers? or r = [ r[0], nil, r[2] ] + http_response_write(client, r) + rescue => e + handle_error(client, e) + end + + # gets rid of stuff the worker has no business keeping track of + # to free some resources and drops all sig handlers. + # traps for USR1, USR2, and HUP may be set in the after_fork Proc + # by the user. + def init_worker_process(worker) + QUEUE_SIGS.each { |sig| trap(sig, nil) } + trap(:CHLD, 'DEFAULT') + SIG_QUEUE.clear + proc_name "worker[#{worker.nr}]" + START_CTX.clear + init_self_pipe! + WORKERS.values.each { |other| other.tmp.close rescue nil } + WORKERS.clear + LISTENERS.each { |sock| sock.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) } + worker.tmp.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) + after_fork.call(self, worker) # can drop perms + worker.user(*user) if user.kind_of?(Array) && ! worker.switched + self.timeout /= 2.0 # halve it for select() + build_app! unless preload_app + end + + def reopen_worker_logs(worker_nr) + logger.info "worker=#{worker_nr} reopening logs..." + Unicorn::Util.reopen_logs + logger.info "worker=#{worker_nr} done reopening logs" + init_self_pipe! + end + + # runs inside each forked worker, this sits around and waits + # for connections and doesn't die until the parent dies (or is + # given a INT, QUIT, or TERM signal) + def worker_loop(worker) + ppid = master_pid + init_worker_process(worker) + nr = 0 # this becomes negative if we need to reopen logs + alive = worker.tmp # tmp is our lifeline to the master process + ready = LISTENERS + + # closing anything we IO.select on will raise EBADF + trap(:USR1) { nr = -65536; SELF_PIPE[0].close rescue nil } + trap(:QUIT) { alive = nil; LISTENERS.each { |s| s.close rescue nil } } + [:TERM, :INT].each { |sig| trap(sig) { exit!(0) } } # instant shutdown + logger.info "worker=#{worker.nr} ready" + m = 0 + + begin + nr < 0 and reopen_worker_logs(worker.nr) + nr = 0 + + # we're a goner in timeout seconds anyways if alive.chmod + # breaks, so don't trap the exception. Using fchmod() since + # futimes() is not available in base Ruby and I very strongly + # prefer temporary files to be unlinked for security, + # performance and reliability reasons, so utime is out. No-op + # changes with chmod doesn't update ctime on all filesystems; so + # we change our counter each and every time (after process_client + # and before IO.select). + alive.chmod(m = 0 == m ? 1 : 0) + + ready.each do |sock| + if client = sock.kgio_tryaccept + process_client(client) + nr += 1 + alive.chmod(m = 0 == m ? 1 : 0) + end + break if nr < 0 + end + + # make the following bet: if we accepted clients this round, + # we're probably reasonably busy, so avoid calling select() + # and do a speculative non-blocking accept() on ready listeners + # before we sleep again in select(). + redo unless nr == 0 # (nr < 0) => reopen logs + + ppid == Process.ppid or return + alive.chmod(m = 0 == m ? 1 : 0) + + # timeout used so we can detect parent death: + ret = IO.select(LISTENERS, nil, SELF_PIPE, timeout) and ready = ret[0] + rescue Errno::EINTR + ready = LISTENERS + rescue Errno::EBADF + nr < 0 or return + rescue => e + if alive + logger.error "Unhandled listen loop exception #{e.inspect}." + logger.error e.backtrace.join("\n") + end + end while alive + end + + # delivers a signal to a worker and fails gracefully if the worker + # is no longer running. + def kill_worker(signal, wpid) + Process.kill(signal, wpid) + rescue Errno::ESRCH + worker = WORKERS.delete(wpid) and worker.tmp.close rescue nil + end + + # delivers a signal to each worker + def kill_each_worker(signal) + WORKERS.keys.each { |wpid| kill_worker(signal, wpid) } + end + + # unlinks a PID file at given +path+ if it contains the current PID + # still potentially racy without locking the directory (which is + # non-portable and may interact badly with other programs), but the + # window for hitting the race condition is small + def unlink_pid_safe(path) + (File.read(path).to_i == $$ and File.unlink(path)) rescue nil + end + + # returns a PID if a given path contains a non-stale PID file, + # nil otherwise. + def valid_pid?(path) + wpid = File.read(path).to_i + wpid <= 0 and return + Process.kill(0, wpid) + wpid + rescue Errno::ESRCH, Errno::ENOENT + # don't unlink stale pid files, racy without non-portable locking... + end + + def load_config! + loaded_app = app + logger.info "reloading config_file=#{config.config_file}" + config[:listeners].replace(init_listeners) + config.reload + config.commit!(self) + kill_each_worker(:QUIT) + Unicorn::Util.reopen_logs + self.app = orig_app + build_app! if preload_app + logger.info "done reloading config_file=#{config.config_file}" + rescue StandardError, LoadError, SyntaxError => e + logger.error "error reloading config_file=#{config.config_file}: " \ + "#{e.class} #{e.message} #{e.backtrace}" + self.app = loaded_app + end + + # returns an array of string names for the given listener array + def listener_names(listeners = LISTENERS) + listeners.map { |io| sock_name(io) } + end + + def build_app! + if app.respond_to?(:arity) && app.arity == 0 + if defined?(Gem) && Gem.respond_to?(:refresh) + logger.info "Refreshing Gem list" + Gem.refresh + end + self.app = app.call + end + end + + def proc_name(tag) + $0 = ([ File.basename(START_CTX[0]), tag + ]).concat(START_CTX[:argv]).join(' ') + end + + def redirect_io(io, path) + File.open(path, 'ab') { |fp| io.reopen(fp) } if path + io.sync = true + end + + def init_self_pipe! + SELF_PIPE.each { |io| io.close rescue nil } + SELF_PIPE.replace(Kgio::Pipe.new) + SELF_PIPE.each { |io| io.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) } + end +end + |