Question

有没有办法让Ruby进程/线程暂停，直到某些外部进程的信号（或其他进程间通信机制）恢复为止？我尝试了以下内容，但线程似乎没有醒来：

this_thread = Thread.current
Thread.new do
  Signal.trap("INT") do
    puts "\nWaking up!"
    this_thread.run
  end
  sleep
end

puts "Going to sleep..."
Thread.stop
puts "Now awake! =)"

示例运行：

$ ruby wake_on_signal.rb 
Going to sleep...
^C
Waking up!
^C
Waking up!
^C
Waking up!

我也尝试过以下方法，它可以运行，但依赖于不断检查某些变量的值，如果可能的话我宁愿避免这样做：

signal_received = false
Signal.trap("INT") do
  puts "\nWaking up!"
  signal_received = true
end

puts "Going to sleep..."
sleep 0.5 until signal_received
puts "Now awake! =)"

示例运行：

$ ruby sleep_until_signal.rb 
Going to sleep...
^C
Waking up!
Now awake! =)

Answer 1

这已经晚了三年，但对未来的读者可能会有所帮助：

puts "kill -#{Signal.list["USR1"]} #{Process.pid}"
thr = Thread.new do
    this_thread = Thread.current
  Signal.trap("USR1") do
    puts "\nWaking up!"
    this_thread.kill
  end
  sleep
end

puts "Going to sleep..."
thr.join
puts "Now awake! =)"

这将暂停主线程并等待USR1信号。它打印出可用于唤醒线程的命令。在我的系统上，打印

$ ruby signal_handler.rb
kill -30 66771  
Going to sleep...

Waking up!
Now awake! =)

Answer 2

您可以使用at_exit执行此操作：

at_exit do
  puts "Now awake! =)"
end

Signal.trap("INT") do
  puts "\nWaking up!"
  exit
end

puts "Going to sleep..."
sleep

示例运行：

$ ruby wake_on_signal.rb 
Going to sleep...
^C
Waking up!
Now awake! =)

Ruby等待来自外部进程的信号

2 个答案: