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puma--puma/lib/puma/cluster.rb
2013-07-05 17:09:18 -07:00

323 lines
6.7 KiB
Ruby

require 'puma/runner'
module Puma
class Cluster < Runner
def initialize(cli)
super cli
@phase = 0
@workers = []
@phased_state = :idle
end
def stop_workers
log "- Gracefully shutting down workers..."
@workers.each { |x| x.term }
begin
Process.waitall
rescue Interrupt
log "! Cancelled waiting for workers"
end
end
def start_phased_restart
@phase += 1
log "- Starting phased worker restart, phase: #{@phase}"
end
class Worker
def initialize(pid, phase)
@pid = pid
@phase = phase
@stage = :started
end
attr_reader :pid, :phase
def booted?
@stage == :booted
end
def boot!
@stage = :booted
end
def term
begin
Process.kill "TERM", @pid
rescue Errno::ESRCH
end
end
end
def spawn_workers
diff = @options[:workers] - @workers.size
upgrade = (@phased_state == :waiting)
diff.times do
pid = fork { worker(upgrade) }
@cli.debug "Spawned worker: #{pid}"
@workers << Worker.new(pid, @phase)
end
if diff > 0
@phased_state = :idle
end
end
def all_workers_booted?
@workers.count { |w| !w.booted? } == 0
end
def check_workers
while @workers.any?
pid = Process.waitpid(-1, Process::WNOHANG)
break unless pid
@workers.delete_if { |w| w.pid == pid }
end
spawn_workers
if @phased_state == :idle && all_workers_booted?
# If we're running at proper capacity, check to see if
# we need to phase any workers out (which will restart
# in the right phase).
#
w = @workers.find { |x| x.phase != @phase }
if w
@phased_state = :waiting
log "- Stopping #{w.pid} for phased upgrade..."
w.term
end
end
end
def wakeup!
begin
@wakeup.write "!" unless @wakeup.closed?
rescue SystemCallError, IOError
end
end
def worker(upgrade)
$0 = "puma: cluster worker: #{@master_pid}"
Signal.trap "SIGINT", "IGNORE"
@master_read.close
@suicide_pipe.close
Thread.new do
IO.select [@check_pipe]
log "! Detected parent died, dying"
exit! 1
end
# Be sure to change the directory again before loading
# the app. This way we can pick up new code.
if upgrade
if dir = @options[:worker_directory]
log "+ Changing to #{dir}"
Dir.chdir dir
end
end
# Invoke any worker boot hooks so they can get
# things in shape before booting the app.
hooks = @options[:worker_boot]
hooks.each { |h| h.call }
min_t = @options[:min_threads]
max_t = @options[:max_threads]
server = Puma::Server.new app, @cli.events
server.min_threads = min_t
server.max_threads = max_t
server.inherit_binder @cli.binder
unless development?
server.leak_stack_on_error = false
end
Signal.trap "SIGTERM" do
server.stop
end
begin
@worker_write << "b#{Process.pid}\n"
rescue SystemCallError, IOError
STDERR.puts "Master seems to have exitted, exitting."
return
end
server.run.join
ensure
@worker_write.close
end
def restart
@restart = true
@status = :stop
wakeup!
end
def phased_restart
return false if @options[:preload_app]
@phased_restart = true
wakeup!
true
end
def stop
@status = :stop
wakeup!
end
def stop_blocked
@status = :stop if @status == :run
wakeup!
Process.waitall
end
def halt
@status = :halt
wakeup!
end
def stats
%Q!{ "workers": #{@workers.size}, "phase": #{@phase} }!
end
def run
@status = :run
output_header "cluster"
log "* Process workers: #{@options[:workers]}"
if @options[:preload_app]
log "* Preloading application"
load_and_bind
else
log "* Phased restart available"
unless @cli.config.app_configured?
error "No application configured, nothing to run"
exit 1
end
@cli.binder.parse @options[:binds], self
end
read, @wakeup = Puma::Util.pipe
Signal.trap "SIGCHLD" do
wakeup!
end
master_pid = Process.pid
Signal.trap "SIGTERM" do
# The worker installs their own SIGTERM when booted.
# Until then, this is run by the worker and the worker
# should just exit if they get it.
if Process.pid != master_pid
log "Early termination of worker"
exit! 0
else
@status = :stop
wakeup!
end
end
@phased_restart = false
if @options[:preload_app]
Signal.trap "SIGUSR1" do
log "App preloaded, phased restart unavailable"
end
else
Signal.trap "SIGUSR1" do
phased_restart
end
end
# Used by the workers to detect if the master process dies.
# If select says that @check_pipe is ready, it's because the
# master has exited and @suicide_pipe has been automatically
# closed.
#
@check_pipe, @suicide_pipe = Puma::Util.pipe
if daemon?
log "* Daemonizing..."
Process.daemon(true)
else
log "Use Ctrl-C to stop"
end
@master_pid = Process.pid
redirect_io
@cli.write_state
@master_read, @worker_write = read, @wakeup
spawn_workers
Signal.trap "SIGINT" do
@status = :stop
wakeup!
end
@cli.events.fire_on_booted!
begin
while @status == :run
begin
res = IO.select([read], nil, nil, 5)
if res
req = read.read_nonblock(1)
if req == "b"
pid = read.gets.to_i
w = @workers.find { |x| x.pid == pid }
if w
w.boot!
log "- Worker #{pid} booted, phase: #{w.phase}"
else
log "! Out-of-sync worker list, no #{pid} worker"
end
end
end
check_workers
if @phased_restart
start_phased_restart
@phased_restart = false
end
rescue Interrupt
@status = :stop
end
end
stop_workers unless @status == :halt
ensure
@check_pipe.close
@suicide_pipe.close
read.close
@wakeup.close
end
end
end
end