在 ruby​​ 中杀死一个名为 using open3 的进程

我正在使用命令行程序，它的工作原理如下：

$ ROUTE_TO_FOLDER/app < "long text"

If “长文本”使用参数编写"app"需要，那么它将用结果填充一个文本文件。如果没有，它将连续用点填充文本文件（我无法处理或修改“app”的代码以避免这种情况）。

在 ruby​​ 脚本中有这样一行：

text = "long text that will be used by app"
output = system("ROUTE_TO_FOLDER/app < #{text}")

现在，如果文本写得好，就不会有问题，我将得到前面提到的输出文件。当文本写得不好时，问题就会出现。接下来发生的事情是我的 ruby​​ 脚本挂起，我不知道如何杀死它。

我发现了Open3 http://www.ruby-doc.org/stdlib-1.9.3/libdoc/open3/rdoc/Open3.html#method-c-popen3我使用了这样的方法：

irb> cmd = "ROUTE_TO_FOLDER/app < #{text}"
irb> stdin, stdout, stderr, wait_thr = Open3.popen3(cmd)
=> [#<IO:fd 10>, #<IO:fd 11>, #<IO:fd 13>, #<Thread:0x007f3a1a6f8820 run>]

当我做：

irb> wait_thr.value

它也挂起，并且：

irb> wait_thr.status
=> "sleep"

我怎样才能避免这些问题？是不是没有意识到“app”失败了？

wait_thr.pid为您提供已启动进程的 pid。做就是了

Process.kill("KILL",wait_thr.pid)

当你需要杀死它的时候。

您可以将其与以两种方式之一检测进程是否挂起（连续输出点）结合起来。

1）设置等待进程的超时时间：

get '/process' do
  text = "long text that will be used by app"
  cmd = "ROUTE_TO_FOLDER/app < #{text}"
  Open3.popen3(cmd) do |i,o,e,w|
    begin
      Timeout.timeout(10) do # timeout set to 10 sec, change if needed
        # process output of the process. it will produce EOF when done.
        until o.eof? do
          # o.read_nonblock(N) ...
        end
      end
    rescue Timeout::Error
      # here you know that the process took longer than 10 seconds
      Process.kill("KILL", w.pid)
      # do whatever other error processing you need
    end
  end
end

2) 检查过程输出。 （下面的代码经过简化 - 您可能不想先将进程的输出读入单个 String buf 然后再进行处理，但我想您已经明白了）。

get '/process' do
  text = "long text that will be used by app"
  cmd = "ROUTE_TO_FOLDER/app < #{text}"
  Open3.popen3(cmd) do |i,o,e,w|
    # process output of the process. it will produce EOF when done. 
    # If you get 16 dots in a row - the process is in the continuous loop
    # (you may want to deal with stderr instead - depending on where these dots are sent to)
    buf = ""
    error = false
    until o.eof? do
      buf << o.read_nonblock(16)
      if buf.size>=16 && buf[-16..-1] == '.'*16
        # ok, the process is hung
        Process.kill("KILL", w.pid)
        error = true
        # you should also get o.eof? the next time you check (or after flushing the pipe buffer),
        # so you will get out of the until o.eof? loop
      end
    end
    if error
      # do whatever error processing you need
    else
      # process buf, it contains all the output
    end
  end
end