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| | require 'logger'
require 'unicorn/socket'
require 'unicorn/const'
require 'unicorn/http_request'
require 'unicorn/http_response'
require 'unicorn/configurator'
require 'unicorn/util'
# Unicorn module containing all of the classes (include C extensions) for running
# a Unicorn web server. It contains a minimalist HTTP server with just enough
# functionality to service web application requests fast as possible.
module Unicorn
class << self
def run(app, options = {})
HttpServer.new(app, options).start.join
end
end
# 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 HttpServer
attr_reader :logger
include ::Unicorn::SocketHelper
DEFAULT_START_CTX = {
:argv => ARGV.map { |arg| arg.dup },
# don't rely on Dir.pwd here since it's not symlink-aware, and
# symlink dirs are the default with Capistrano...
:cwd => `/bin/sh -c pwd`.chomp("\n"),
:zero => $0.dup,
:environ => {}.merge!(ENV),
:umask => File.umask,
}.freeze
Worker = Struct.new(:nr, :tempfile) unless defined?(Worker)
class Worker
# worker objects may be compared to just plain numbers
def ==(other_nr)
self.nr == other_nr
end
end
# 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.workers.join to join the thread that's processing
# incoming requests on the socket.
def initialize(app, options = {})
start_ctx = options.delete(:start_ctx)
@start_ctx = DEFAULT_START_CTX.dup
@start_ctx.merge!(start_ctx) if start_ctx
@app = app
@sig_queue = []
@master_pid = $$
@workers = Hash.new
@io_purgatory = [] # prevents IO objects in here from being GC-ed
@request = @rd_sig = @wr_sig = nil
@reexec_pid = 0
@config = Configurator.new(options.merge(:use_defaults => true))
@listener_opts = {}
@config.commit!(self, :skip => [:listeners, :pid])
@listeners = []
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 UNIXServer or TCPServer
inherited = ENV['UNICORN_FD'].to_s.split(/,/).map do |fd|
io = Socket.for_fd(fd.to_i)
set_server_sockopt(io)
@io_purgatory << io
logger.info "inherited: #{io} fd=#{fd} addr=#{sock_name(io)}"
server_cast(io)
end
config_listeners = @config[:listeners].dup
@listeners.replace(inherited)
# we start out with generic Socket objects that get cast to either
# TCPServer or 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
end
config_listeners.each { |addr| listen(addr) }
raise ArgumentError, "no listeners" if @listeners.empty?
self.pid = @config[:pid]
build_app! if @preload_app
$stderr.reopen(File.open(@stderr_path, "a")) if @stderr_path
$stdout.reopen(File.open(@stdout_path, "a")) if @stdout_path
$stderr.sync = $stdout.sync = true
spawn_missing_workers
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 = listener_names
set_names = listener_names(listeners)
dead_names = cur_names - set_names
@listeners.delete_if do |io|
if dead_names.include?(sock_name(io))
@io_purgatory.delete_if { |pio| pio.fileno == io.fileno }
true
else
false
end
end
(set_names - cur_names).each { |addr| listen(addr) }
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 == $$
raise ArgumentError, "Already running on PID:#{x} " \
"(or pid=#{path} is stale)"
end
end
unlink_pid_safe(@pid) if @pid
File.open(path, 'wb') { |fp| fp.syswrite("#$$\n") } if path
@pid = path
end
# add a given address to the +listeners+ set, idempotently
# Allows workers to add a private, per-process listener via the
# @after_fork hook. Very useful for debugging and testing.
def listen(address, opt = {}.merge(@listener_opts[address] || {}))
return if String === address && listener_names.include?(address)
if io = bind_listen(address, opt)
if Socket == io.class
@io_purgatory << io
io = server_cast(io)
end
logger.info "#{io} listening on PID:#{$$} " \
"fd=#{io.fileno} addr=#{sock_name(io)}"
@listeners << io
else
logger.error "adding listener failed addr=#{address} (in use)"
raise Errno::EADDRINUSE, address
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
# this pipe is used to wake us up from select(2) in #join when signals
# are trapped. See trap_deferred
@rd_sig, @wr_sig = IO.pipe unless (@rd_sig && @wr_sig)
mode = nil
respawn = true
QUEUE_SIGS.each { |sig| trap_deferred(sig) }
trap(:CHLD) { |sig_nr| awaken_master }
$0 = "unicorn master"
logger.info "master process ready" # test_exec.rb relies on this message
begin
loop do
reap_all_workers
case (mode = @sig_queue.shift)
when nil
murder_lazy_workers
spawn_missing_workers if respawn
master_sleep
when :QUIT # graceful shutdown
break
when :TERM, :INT # immediate shutdown
stop(false)
break
when :USR1 # rotate logs
logger.info "master rotating logs..."
Unicorn::Util.reopen_logs
logger.info "master done rotating 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 != $$
respawn = false
logger.info "gracefully stopping all workers"
kill_each_worker(:QUIT)
else
logger.info "SIGWINCH ignored because we're not daemonized"
end
when :HUP
respawn = true
if @config.config_file
load_config!
redo # immediate reaping since we may have QUIT workers
else # exec binary and exit if there's no config file
logger.info "config_file not present, reexecuting binary"
reexec
break
end
else
logger.error "master process in unknown mode: #{mode}"
end
end
rescue Errno::EINTR
retry
rescue Object => e
logger.error "Unhandled master loop exception #{e.inspect}."
logger.error e.backtrace.join("\n")
retry
end
stop # gracefully shutdown all workers on our way out
logger.info "master PID:#{$$} join complete"
unlink_pid_safe(@pid) if @pid
end
# Terminates all workers, but does not exit master process
def stop(graceful = true)
kill_each_worker(graceful ? :QUIT : :TERM)
timeleft = @timeout
step = 0.2
reap_all_workers
until @workers.empty?
sleep(step)
reap_all_workers
(timeleft -= step) > 0 and next
kill_each_worker(:KILL)
end
ensure
self.listeners = []
end
private
# list of signals we care about and trap in master.
QUEUE_SIGS = [ :WINCH, :QUIT, :INT, :TERM, :USR1, :USR2, :HUP ].freeze
# 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
begin
ready = IO.select([@rd_sig], nil, nil, 1)
ready && ready[0] && ready[0][0] or return
loop { @rd_sig.read_nonblock(Const::CHUNK_SIZE) }
rescue Errno::EAGAIN, Errno::EINTR
end
end
def awaken_master
begin
@wr_sig.write_nonblock('.') # wakeup master process from IO.select
rescue Errno::EAGAIN, Errno::EINTR
# pipe is full, master should wake up anyways
retry
end
end
# reaps all unreaped workers
def reap_all_workers
begin
loop do
pid, status = Process.waitpid2(-1, Process::WNOHANG)
pid or break
if @reexec_pid == pid
logger.error "reaped #{status.inspect} exec()-ed"
@reexec_pid = 0
self.pid = @pid.chomp('.oldbin') if @pid
$0 = "unicorn master"
else
worker = @workers.delete(pid)
worker.tempfile.close rescue nil
logger.info "reaped #{status.inspect} " \
"worker=#{worker.nr rescue 'unknown'}"
end
end
rescue Errno::ECHILD
end
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
@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 Object => e
logger.error "error writing pid=#{old_pid} #{e.class} #{e.message}"
return
end
end
@reexec_pid = fork do
@rd_sig.close if @rd_sig
@wr_sig.close if @wr_sig
@workers.values.each { |other| other.tempfile.close rescue nil }
ENV.replace(@start_ctx[:environ])
ENV['UNICORN_FD'] = @listeners.map { |sock| sock.fileno }.join(',')
File.umask(@start_ctx[:umask])
Dir.chdir(@start_ctx[:cwd])
cmd = [ @start_ctx[:zero] ] + @start_ctx[:argv]
logger.info "executing #{cmd.inspect} (in #{Dir.pwd})"
@before_exec.call(self) if @before_exec
exec(*cmd)
end
$0 = "unicorn master (old)"
end
# forcibly terminate all workers that haven't checked in in @timeout
# seconds. The timeout is implemented using an unlinked tempfile
# shared between the parent process and each worker. The worker
# runs File#chmod to modify the ctime of the tempfile. If the ctime
# is stale for >@timeout seconds, then we'll kill the corresponding
# worker.
def murder_lazy_workers
now = Time.now
@workers.each_pair do |pid, worker|
(now - worker.tempfile.ctime) <= @timeout and next
logger.error "worker=#{worker.nr} PID:#{pid} is too old, killing"
kill_worker(:KILL, pid) # take no prisoners for @timeout violations
worker.tempfile.close rescue nil
end
end
def spawn_missing_workers
return if @workers.size == @worker_processes
(0...@worker_processes).each do |worker_nr|
@workers.values.include?(worker_nr) and next
begin
Dir.chdir(@start_ctx[:cwd])
rescue Errno::ENOENT => err
logger.fatal "#{err.inspect} (#{@start_ctx[:cwd]})"
@sig_queue << :QUIT # forcibly emulate SIGQUIT
return
end
tempfile = Tempfile.new('') # as short as possible to save dir space
tempfile.unlink # don't allow other processes to find or see it
tempfile.sync = true
worker = Worker.new(worker_nr, tempfile)
@before_fork.call(self, worker.nr)
pid = fork { worker_loop(worker) }
@workers[pid] = worker
end
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)
client.nonblock = false
set_client_sockopt(client) if TCPSocket === client
env = @request.read(client)
app_response = @app.call(env)
HttpResponse.write(client, app_response)
# 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
rescue EOFError,Errno::ECONNRESET,Errno::EPIPE,Errno::EINVAL,Errno::EBADF
client.write_nonblock(Const::ERROR_500_RESPONSE) rescue nil
rescue HttpParserError # try to tell the client they're bad
client.write_nonblock(Const::ERROR_400_RESPONSE) rescue nil
rescue Object => e
client.write_nonblock(Const::ERROR_500_RESPONSE) rescue nil
logger.error "Read error: #{e.inspect}"
logger.error e.backtrace.join("\n")
ensure
begin
client.closed? or client.close
rescue Object => e
logger.error "Client error: #{e.inspect}"
logger.error e.backtrace.join("\n")
end
@request.reset
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)
build_app! unless @preload_app
@sig_queue.clear
QUEUE_SIGS.each { |sig| trap(sig, 'IGNORE') }
trap(:CHLD, 'DEFAULT')
$0 = "unicorn worker[#{worker.nr}]"
@rd_sig.close if @rd_sig
@wr_sig.close if @wr_sig
@workers.values.each { |other| other.tempfile.close rescue nil }
@workers.clear
@start_ctx.clear
@start_ctx = @workers = @rd_sig = @wr_sig = nil
@listeners.each { |sock| set_cloexec(sock) }
ENV.delete('UNICORN_FD')
@after_fork.call(self, worker.nr) if @after_fork
@request = HttpRequest.new(logger)
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)
init_worker_process(worker)
nr = 0
tempfile = worker.tempfile
alive = true
ready = @listeners
client = nil
[:TERM, :INT].each { |sig| trap(sig) { exit(0) } } # instant shutdown
trap(:QUIT) do
alive = false
@listeners.each { |sock| sock.close rescue nil } # break IO.select
end
reopen_logs, (rd, wr) = false, IO.pipe
trap(:USR1) { reopen_logs = true; rd.close rescue nil } # break IO.select
@logger.info "worker=#{worker.nr} ready"
while alive && @master_pid == Process.ppid
if reopen_logs
reopen_logs = false
@logger.info "worker=#{worker.nr} rotating logs..."
Unicorn::Util.reopen_logs
@logger.info "worker=#{worker.nr} done rotating logs"
wr.close rescue nil
rd, wr = IO.pipe
end
# we're a goner in @timeout seconds anyways if tempfile.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 increment our counter each and every time.
tempfile.chmod(nr += 1)
begin
accepted = false
ready.each do |sock|
begin
client = begin
sock.accept_nonblock
rescue Errno::EAGAIN
next
end
accepted = true
process_client(client)
rescue Errno::ECONNABORTED
# client closed the socket even before accept
client.close rescue nil
end
tempfile.chmod(nr += 1)
break if reopen_logs
end
client = nil
# make the following bet: if we accepted clients this round,
# we're probably reasonably busy, so avoid calling select(2)
# and try to do a blind non-blocking accept(2) on everything
# before we sleep again in select
if accepted || reopen_logs
ready = @listeners
else
begin
tempfile.chmod(nr += 1)
# timeout used so we can detect parent death:
ret = IO.select(@listeners, nil, [rd], @timeout/2.0) or next
ready = ret[0]
rescue Errno::EINTR
ready = @listeners
rescue Errno::EBADF => e
reopen_logs or exit(alive ? 1 : 0)
end
end
rescue SystemExit => e
exit(e.status)
rescue Object => e
if alive
logger.error "Unhandled listen loop exception #{e.inspect}."
logger.error e.backtrace.join("\n")
end
end
end
end
# delivers a signal to a worker and fails gracefully if the worker
# is no longer running.
def kill_worker(signal, pid)
begin
Process.kill(signal, pid)
rescue Errno::ESRCH
worker = @workers.delete(pid) and worker.tempfile.close rescue nil
end
end
# delivers a signal to each worker
def kill_each_worker(signal)
@workers.keys.each { |pid| kill_worker(signal, pid) }
end
# unlinks a PID file at given +path+ if it contains the current PID
# useful as an at_exit handler.
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)
if File.exist?(path) && (pid = File.read(path).to_i) > 1
begin
Process.kill(0, pid)
return pid
rescue Errno::ESRCH
end
end
nil
end
def load_config!
begin
logger.info "reloading config_file=#{@config.config_file}"
@config.reload
@config.commit!(self)
kill_each_worker(:QUIT)
logger.info "done reloading config_file=#{@config.config_file}"
rescue Object => e
logger.error "error reloading config_file=#{@config.config_file}: " \
"#{e.class} #{e.message}"
end
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!
@app = @app.call if @app.respond_to?(:arity) && @app.arity == 0
end
end
end
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