如何使Bluepill仅在达到安全状态后重启Resque工作进程

Question

假设这是我的工人：

class FooWorker
  @queue = :foo

  def self.perform
    User.all.each do |u|
      ...
      Do Long Operations (Unsafe to kill)
      ...

      # Here it's safe to break the worker and restart
    end
  end
end

我正在用Resque Scheduler查询，这是我的Bluepill配置文件：

...
app.process(process_name) do |process|
  process.group         = "resque"
  process.start_command = "rake environment resque:work QUEUE=foo RAILS_ENV=production"
  ...
  process.stop_signals  = [:quit, 5.seconds, :term, 1.minute, :kill]
  process.daemonize     = true

  process.start_grace_time = 30.seconds
  process.stop_grace_time  = 80.seconds

  process.monitor_children do |child_process|
    child_process.stop_command = "kill -QUIT {{PID}}"

    child_process.checks :mem_usage, :every => 30.seconds, :below => 500.megabytes, :times => [3,4], :fires => :stop
  end
end
....

我想让Bluepill或Resque等待，直到它到达“安全”块才能重新启动或关闭。如何做到这一点？

Answer 1

这样试试：

1)通过在启动时设置TERM_CHILD和RESQUE_TERM_TIMEOUT环境变量，将resque设置为在TERM/INT上使用new_kill_child方法优雅地杀死孩子：

process.start_command = "rake environment resque:work QUEUE=foo RAILS_ENV=production TERM_CHILD=1 RESQUE_TERM_TIMEOUT=20.0"

RESQUE_TERM_TIMEOUT的默认值为4 seconds。

这将使resque向子进程发送TERM信号，等待RESQUE_TERM_TIMEOUT，如果子进程仍在运行，则终止它。一定要

a)将此超时设置得足够大，以使您的临界区结束，

b)将process.stop_signals中的Bluepill TERM timeout配置为比RESQUE_TERM_TIMEOUT稍大一点，以便在worker等待子进程结束临界区时不杀死worker。

2)处理子进程中的TERM信号，使其正常停止：

class FooWorker
  class << self
    attr_accessor :stop
  end

  @queue = :foo
  def self.perform
    User.all.each do |u|
      ...
      Do Long Operations (Unsafe to kill)
      ...

      # Here it's safe to break the worker and restart
      return if FooWorker.stop
    end
  end
end

trap('TERM') do
  FooWorker.stop = true
end