Run a process and kill it if it doesn't end within one hour

Federico_Ramponi_18770 0
Viewed 37307

I need to do the following in Python. I want to spawn a process (subprocess module?), and:

  • if the process ends normally, to continue exactly from the moment it terminates;
  • if, otherwise, the process "gets stuck" and doesn't terminate within (say) one hour, to kill it and continue (possibly giving it another try, in a loop).

What is the most elegant way to accomplish this?

kill process python
5 Answers

A nice, passive, way is also by using a threading.Timer and setting up callback function.

from threading import Timer

# execute the command
p = subprocess.Popen(command)

# save the proc object - either if you make this onto class (like the example), or 'p' can be global
self.p == p

# config and init timer
# kill_proc is a callback function which can also be added onto class or simply a global
t = Timer(seconds, self.kill_proc)

# start timer
t.start()

# wait for the test process to return
rcode = p.wait()

t.cancel()

If the process finishes in time, wait() ends and code continues here, cancel() stops the timer. If meanwhile the timer runs out and executes kill_proc in a separate thread, wait() will also continue here and cancel() will do nothing. By the value of rcode you will know if we've timeouted or not. Simplest kill_proc: (you can of course do anything extra there)

def kill_proc(self):
    os.kill(self.p, signal.SIGTERM)
user_3384010

Koodos to Peter Shinners for his nice suggestion about subprocess module. I was using exec() before and did not have any control on running time and especially terminating it. My simplest template for this kind of task is the following and I am just using the timeout parameter of subprocess.run() function to monitor the running time. Of course you can get standard out and error as well if needed:

from subprocess import run, TimeoutExpired, CalledProcessError

for file in fls:
    try:
        run(["python3.7", file], check=True, timeout=7200)  # 2 hours timeout
        print("scraped :)", file)
    except TimeoutExpired:
        message = "Timeout :( !!!"
        print(message, file)
        f.write("{message} {file}\n".format(file=file, message=message))
    except CalledProcessError:
        message = "SOMETHING HAPPENED :( !!!, CHECK"
        print(message, file)
        f.write("{message} {file}\n".format(file=file, message=message))
user_61121180
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