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| | # -*- encoding: binary -*-
# Copyright (C) 2013, Eric Wong <normalperson@yhbt.net> and all contributors
# License: GPLv3 or later (https://www.gnu.org/licenses/gpl-3.0.txt)
module Yahns::ServerMP # :nodoc:
EXIT_SIGS = [ :QUIT, :TERM, :INT ]
def maintain_worker_count
(off = @workers.size - @worker_processes) == 0 and return
off < 0 and return spawn_missing_workers
@workers.each do |wpid, worker|
worker.nr >= @worker_processes and Process.kill(:QUIT, wpid)
end
end
# delivers a signal to each worker
def kill_each_worker(signal)
@workers.each_key { |wpid| Process.kill(signal, wpid) }
end
# this is the first thing that runs after forking in a child
# 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 worker_atfork_internal(worker)
worker.atfork_child
# daemon_pipe may be true for non-initial workers
@daemon_pipe = @daemon_pipe.close if @daemon_pipe.respond_to?(:close)
srand # in case this pops up again: https://bugs.ruby-lang.org/issues/4338
# The OpenSSL PRNG is seeded with only the pid, and apps with frequently
# dying workers can recycle pids
OpenSSL::Random.seed(rand.to_s) if defined?(OpenSSL::Random)
# we'll re-trap EXIT_SIGS later for graceful shutdown iff we accept clients
EXIT_SIGS.each { |sig| trap(sig) { exit!(0) } }
exit!(0) if (@sig_queue & EXIT_SIGS)[0] # did we inherit sigs from parent?
@sig_queue = []
# ignore WINCH, TTIN, TTOU, HUP in the workers
(Yahns::Server::QUEUE_SIGS - EXIT_SIGS).each { |sig| trap(sig, nil) }
trap(:CHLD, 'DEFAULT')
@logger.info("worker=#{worker.nr} spawned pid=#$$")
proc_name "worker[#{worker.nr}]"
Yahns::START.clear
@sev.close
@sev = Yahns::Sigevent.new
switch_user(*@user) if @user
@user = @workers = nil
__call_hooks(@atfork_child, worker.nr)
@atfork_child = @atfork_parent = @atfork_prepare = nil
end
def __call_hooks(ary, worker_nr)
ary.each { |x| x.call(worker_nr) } if ary
end
def spawn_missing_workers
worker_nr = -1
until (worker_nr += 1) == @worker_processes
@workers.value?(worker_nr) and next
worker = Yahns::Worker.new(worker_nr)
@logger.info("worker=#{worker_nr} spawning...")
__call_hooks(@atfork_prepare, worker_nr)
if pid = fork
@workers[pid] = worker.atfork_parent
# XXX is this useful?
__call_hooks(@atfork_parent, worker_nr)
else
worker_atfork_internal(worker)
run_mp_worker(worker)
end
end
rescue => e
Yahns::Log.exception(@logger, "spawning worker", e)
exit!
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
spawn_missing_workers
state = :respawn # :QUIT, :WINCH
proc_name 'master'
@logger.info "master process ready"
daemon_ready
begin
@sev.kgio_wait_readable
@sev.yahns_step
reap_all
case @sig_queue.shift
when *EXIT_SIGS # graceful shutdown (twice for non graceful)
@listeners.each(&:close).clear
kill_each_worker(:QUIT)
state = :QUIT
when :USR1 # rotate logs
usr1_reopen("master ")
kill_each_worker(:USR1)
when :USR2 # exec binary, stay alive in case something went wrong
reexec
when :WINCH
if @daemon_pipe
state = :WINCH
@logger.info "gracefully stopping all workers"
kill_each_worker(:QUIT)
@worker_processes = 0
else
@logger.info "SIGWINCH ignored because we're not daemonized"
end
when :TTIN
state = :respawn unless state == :QUIT
@worker_processes += 1
when :TTOU
@worker_processes -= 1 if @worker_processes > 0
when :HUP
state = :respawn unless state == :QUIT
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 while @sig_queue[0]
maintain_worker_count if state == :respawn
rescue => e
Yahns::Log.exception(@logger, "master loop error", e)
end while state != :QUIT || @workers.size > 0
@logger.info "master complete"
unlink_pid_safe(@pid) if @pid
end
def fdmap_init_mp
fdmap = fdmap_init # builds apps (if not preloading)
[:USR1, *EXIT_SIGS].each { |sig| trap(sig) { sqwakeup(sig) } }
@config.postfork_cleanup # reduce live objects
fdmap
end
def run_mp_worker(worker)
fdmap = fdmap_init_mp
alive = true
watch = [ worker, @sev ]
begin
alive = mp_sig_handle(watch, alive)
rescue => e
Yahns::Log.exception(@logger, "main worker loop", e)
end while alive || dropping(fdmap)
exit
ensure
quit_finish
end
def mp_sig_handle(watch, alive)
# not performance critical
watch.delete_if { |io| io.to_io.closed? }
if r = IO.select(watch, nil, nil, alive ? nil : 0.01)
r[0].each(&:yahns_step)
end
case @sig_queue.shift
when *EXIT_SIGS
return quit_enter(alive)
when :USR1
usr1_reopen("worker ")
end
alive
end
# reaps all unreaped workers/reexec processes
def reap_all
begin
wpid, status = Process.waitpid2(-1, Process::WNOHANG)
wpid or return
if @reexec_pid == wpid
@logger.error "reaped #{status.inspect} exec()-ed"
@reexec_pid = 0
self.pid = @pid.chomp('.oldbin') if @pid
proc_name('master')
else
worker = @workers.delete(wpid)
desc = worker ? "worker=#{worker.nr}" : "(unknown)"
m = "reaped #{status.inspect} #{desc}"
status.success? ? @logger.info(m) : @logger.error(m)
end
rescue Errno::ECHILD
return
end while true
end
end
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