import os

import sys

import time

import shlex

import random

import signal

import subprocess

def demo_subprocess_run():

tmp0 = round(random.uniform(0.233, 0.466), 3)

print(f'sleep for {tmp0} seconds')

time0 = time.time()

subprocess.run(['sleep', f'{tmp0}s']) #block until subprocess finish

print(f'actually pass {time.time() - time0} seconds')

def demo_split_shell():

tmp0 = '''

/bin/vikings -input eggs.txt -output "spam spam.txt" -cmd "echo '$MONEY'"

'''

shlex.split(tmp0.strip())

def demo_start_process_non_blocking():

# https://stackoverflow.com/a/16071877

time0 = time.time()

print('start process "sleep 0.5" without blocking')

proc = subprocess.Popen(['sleep', '0.5'])

# while proc.poll() is None:

while True:

poll_ret = proc.poll() #if not call proc.poll(), proc.returncode will always be "None"

print(f'poll_ret is "{poll_ret}", proc.returncode is "{proc.returncode}"')

if poll_ret is not None:

break

tmp0 = round(time.time() - time0, 2)

print(f'process still running, {tmp0} seconds')

time.sleep(0.1)

tmp0 = round(time.time() - time0, 2)

print(f'process exited with returncode "{proc.returncode}", {tmp0} seconds')

def demo_kill_nonblocking_process():

# https://stackoverflow.com/a/4791612

print('start process "sleep 0.5" without blocking')

time0 = time.time()

proc = subprocess.Popen(['sleep', '0.5'], preexec_fn=os.setsid)

tmp0 = round(time.time()-time0, 2)

print(f'main process sleep 0.2 seconds, {tmp0} seconds')

time.sleep(0.2)

tmp0 = round(time.time()-time0, 2)

print(f'main process kill subprocess, {tmp0} seconds')

os.killpg(os.getpgid(proc.pid), signal.SIGTERM) # Send the signal to all the process groups

tmp0 = round(time.time()-time0, 2)

print(f'subprocess killed with returncode "{proc.returncode}", {tmp0} seconds')