Question

我目前正在使用Python模块Spynner来自动执行某些Web任务。我遇到了一个问题，虽然由于某种原因，该过程只是停止移动，冻结但仍然响应Windows。

我想要做的是设置某种形式的监视器来检查是否发生这种情况，然后重新启动该过程。我在考虑可能监视程序的终端输出，如果它在一定时间后停止推送数据，它会终止程序并重新启动。

我知道如何杀死程序并再次运行它，只需使用操作系统和子进程，但我不知道如何设置监视终端是否停止在特定时间内发送数据

Answer 1

以下代码是从“Non-blocking read on a subprocess.PIPE in python”借用并稍加修改的（对J.F. Sebastian的赞誉 - 如果您接受此答案，请提交原始代码）

import sys
import time
from subprocess import PIPE, Popen
from threading  import Thread

try:
    from Queue import Queue, Empty
except ImportError:
    from queue import Queue, Empty  # python 3.x

ON_POSIX = 'posix' in sys.builtin_module_names

def enqueue_output(out, queue):
    for line in iter(out.readline, b''):
        timestamp = time.time( )
        queue.put((timestamp, line))
    out.close()

#-- This is how long you're willing to wait before you 
#-- consider your Spynner process to be brain-dead.
MAX_WAIT_TIME = 300.0  #-- we'll wait 5 minutes (300 seconds)

#-- Construct a shared queue that will be used to send messages from 
#-- the subprocess I/O polling thread to the watchdog (main) thread.
q = Queue()

#-- Spawn your subprocess...
p = Popen(['myprogram.exe'], stdout=PIPE, bufsize=1, close_fds=ON_POSIX)

#-- Create a new thread that runs in the same process as the watchdog.
#-- This thread will poll the output of the subprocess and populate the 
#-- shared queue.
t = Thread(target=enqueue_output, args=(p.stdout, q))
t.daemon = True # thread dies with the program
t.start()

#-- Now, we'll try to read from the shared queue.
try:
    #-- Queries the shared queue for the next item in the queue,
    #-- waiting for up to MAX_WAIT_TIME before failing with an Empty exception.
    timestamp, line = q.get(True, MAX_WAIT_TIME)
except Empty:
    #-- Ok...the queue is empty and it's been MAX_WAIT_TIME since
    #-- We've pulled anything from the queue.
    p.terminate( )  #-- "terminate with extreme prejudice"
else: # got line
    #-- Got a (timestamp, line_of_text) pair, where the timestamp is the
    #-- system time when the I/O polling thread grabbed the line from
    #-- the subprocess pipe.  This timestamp isn't strictly necessary,
    #-- but might come in handy in debugging the brain-dead Spynner process.
    #-- So now...do something with that line of text!
    doSomething(line)

你必须使用一些逻辑来增加这个代码，以产生一个新的Spynner进程，以便在已终止的进程中取出等等，但希望这可以让你知道如何继续。

监控程序崩溃

1 个答案: