执行相同的进程 N 次，如果未在 X 秒内完成，则终止它

Question

我有一个外部过程，它需要一些随机的时间来运行，最后它在标准输出中打印了一些输出。

我需要编写一个运行此类外部过程n次的Python过程；x秒后，对于已经终止的每个过程必须收集输出，对于尚未终止的过程，必须杀死它。

您将如何做？

Answer 1

您可以使用内置API：

http://strftime.org/
https://docs.python.org/3.5/library/time.html

start_time = time.time()
# your code
elapsed_time = time.time() - start_time
time.strftime("%H:%M:%S", time.gmtime(elapsed_time))
#'00:00:02'

要杀死该过程，我不知道您是如何处理的：

您可以使用：

import subprocess, signal 
p = subprocess.Popen(['ps', '-A'], stdout=subprocess.PIPE)
out, err = p.communicate()
for line in out.splitlines():
   if 'iChat' in line:
   pid = int(line.split(None, 1)[0])
   os.kill(pid, signal.SIGKILL) # -9 (equivalent.)

Answer 2

您可以使用apscheduler模块。一个（快速而肮脏的）示例：

from apscheduler.schedulers.background import BlockingScheduler
count = 0
N = 10 # Change this per your requirement
def run_external_process():
    global count, scheduler
    # Execute the job N times
    count = count + 1
    if count == 10: # Shutdown the scheduler and exit
        scheduler.shutdown(wait=False)
        sys.exit(1)
    #Run your code here
# When each job is executed check for its output 
def listen_for_output():
   if event.retval: # Check the return value of your external process
       # Collect output
   else:
       # Call script to terminate process
try:
    scheduler = BlockingScheduler() # Initiate your scheduler
except ImportError:
    raise ImportError('Failed to import module')
sys.exit(1)  
scheduler.add_job(run_external_process, 'interval', seconds=1, id='my_job_id')
# Add a listener to check the output of your external process
scheduler.add_listener(listen_for_output, EVENT_JOB_EXECUTED|EVENT_JOB_ERROR) 
scheduler.start()