class Server::Starter::ResqueListener

Public Class Methods

graceful_restart(starter, worker, worker_nr, status_file) click to toggle source

This allows a new master process to incrementally phase out the old master process with SIGTTOU. The last worker spawned will then kill off the old master process with a SIGQUIT.

@param starter [ResqueStarter] @param worker [Resque::Worker] @param worker_nr [Integer] worker number @param status_file [String] path to Server::Starter status file (–status-file)

# File lib/server/starter/resque_listener.rb, line 14
def self.graceful_restart(starter, worker, worker_nr, status_file)
  pids = File.readlines(status_file).map {|_| _.chomp.split(':') }.to_h
  old_gen = ENV['SERVER_STARTER_GENERATION'].to_i - 1
  if old_pid = pids[old_gen.to_s]
    sig = (worker_nr + 1) >= starter.num_workers ? :QUIT : :TTOU
    Process.kill(sig, old_pid.to_i)
    while starter.old_workers.size > starter.num_workers
      sleep 0.1
    end
  end
rescue Errno::ENOENT, Errno::ESRCH => e
  $stderr.puts "#{e.class} #{e.message}"
end