루비에서 UNIX 프로세스 제어 방법 사용

Question

Ryan Tomayko는 화재 폭풍을 쳤다 이 게시물 UNIX 프로세스 제어 명령 사용 정보.

우리는 더 많은 일을해야합니다. 더 많은 것. 나는 Fork (2), execve (2), Pipe (2), SocketPair (2), Select (2), Kill (2), Sigaction (2) 등에 대해 이야기하고 있습니다. 이들은 우리의 친구입니다. 그들은 우리를 돕기 위해 너무 심하게 원합니다.

나는 약간의 코드가 있습니다 (a delayed_job 이것에 맞는 DataMapper 용 클론이지만, 나열된 명령을 활용하는 방법은 명확하지 않습니다. 이 코드를 개선하는 방법에 대한 아이디어가 있습니까?

def start
  say "*** Starting job worker #{@name}"
  t = Thread.new do
    loop do
      delay = Update.work_off(self)
      break if $exit
      sleep delay
      break if $exit
    end
    clear_locks
  end

  trap('TERM') { terminate_with t }
  trap('INT')  { terminate_with t }

  trap('USR1') do
    say "Wakeup Signal Caught"
    t.run
  end
end

Answer 1

Ahh yes... the dangers of "We should do more of this" without explaining what each of those do and in what circumstances you'd use them. For something like delayed_job you may even be using fork without knowing that you're using fork. That said, it really doesn't matter. Ryan was talking about using fork for preforking servers. delayed_job would use fork for turning a process into a daemon. Same system call, different purposes. Running delayed_job in the foreground (without fork) vs in the background (with fork) will result in a negligible performance difference.

However, if you write a server that accepts concurrent connections, now Ryan's advice is right on the money.

• fork: creates a copy of the original process
• execve: stops executing the current file and begins executing a new file in the same process (very useful in rake tasks)
• pipe: creates a pipe (two file descriptors, one for read, one for write)
• socketpair: like a pipe, but for sockets
• select: let's you wait for one or more of multiple file descriptors to be ready with a timeout
• kill: used to send a signal to a process
• sigaction: lets you change what happens when a process receives a signal

Answer 2

5 months later, you can view my solution at http://github.com/antarestrader/Updater. Look at lib/updater/fork_worker.rb