143 lines
2.3 KiB
Ruby
143 lines
2.3 KiB
Ruby
module Demon; end
|
|
|
|
# intelligent fork based demonizer
|
|
class Demon::Base
|
|
|
|
def self.start(count)
|
|
@demons ||= {}
|
|
count.times do |i|
|
|
(@demons["#{prefix}_#{i}"] ||= new(i)).start
|
|
end
|
|
end
|
|
|
|
def self.stop
|
|
return unless @demons
|
|
@demons.values.each do |demon|
|
|
demon.stop
|
|
end
|
|
end
|
|
|
|
def initialize(index)
|
|
@index = index
|
|
@pid = nil
|
|
@parent_pid = Process.pid
|
|
@monitor = nil
|
|
end
|
|
|
|
def pid_file
|
|
"#{Rails.root}/tmp/pids/#{self.class.prefix}_#{@index}.pid"
|
|
end
|
|
|
|
def stop
|
|
if @monitor
|
|
@monitor.kill
|
|
@monitor.join
|
|
@monitor = nil
|
|
end
|
|
|
|
if @pid
|
|
Process.kill("HUP",@pid)
|
|
@pid = nil
|
|
end
|
|
end
|
|
|
|
def start
|
|
if existing = already_running?
|
|
# should not happen ... so kill violently
|
|
Process.kill("TERM",existing)
|
|
end
|
|
|
|
return if @pid
|
|
|
|
if @pid = fork
|
|
write_pid_file
|
|
monitor_child
|
|
return
|
|
end
|
|
|
|
monitor_parent
|
|
establish_app
|
|
after_fork
|
|
end
|
|
|
|
def already_running?
|
|
if File.exists? pid_file
|
|
pid = File.read(pid_file).to_i
|
|
if alive?(pid)
|
|
return pid
|
|
end
|
|
end
|
|
|
|
nil
|
|
end
|
|
|
|
private
|
|
|
|
def monitor_child
|
|
@monitor ||= Thread.new do
|
|
while true
|
|
sleep 5
|
|
unless alive?(@pid)
|
|
STDERR.puts "#{@pid} died, restarting the process"
|
|
@pid = nil
|
|
start
|
|
end
|
|
end
|
|
end
|
|
end
|
|
|
|
def write_pid_file
|
|
FileUtils.mkdir_p(Rails.root + "tmp/pids")
|
|
File.open(pid_file,'w') do |f|
|
|
f.write(@pid)
|
|
end
|
|
end
|
|
|
|
def delete_pid_file
|
|
File.delete(pid_file)
|
|
end
|
|
|
|
def monitor_parent
|
|
Thread.new do
|
|
while true
|
|
unless alive?(@parent_pid)
|
|
Process.kill "QUIT", Process.pid
|
|
end
|
|
sleep 1
|
|
end
|
|
end
|
|
end
|
|
|
|
def alive?(pid)
|
|
begin
|
|
Process.getpgid(pid)
|
|
true
|
|
rescue Errno::ESRCH
|
|
false
|
|
end
|
|
end
|
|
|
|
def establish_app
|
|
ActiveRecord::Base.connection_handler.clear_active_connections!
|
|
ActiveRecord::Base.establish_connection
|
|
$redis.client.reconnect
|
|
Rails.cache.reconnect
|
|
MessageBus.after_fork
|
|
|
|
Signal.trap("HUP") do
|
|
begin
|
|
delete_pid_file
|
|
ensure
|
|
exit
|
|
end
|
|
end
|
|
|
|
# keep stuff simple for now
|
|
$stdout.reopen("/dev/null", "w")
|
|
$stderr.reopen("/dev/null", "w")
|
|
end
|
|
|
|
def after_fork
|
|
end
|
|
end
|