从父流程中断开子流程循环

Question

这里缺少什么来中断tok1.py中tok2.py中的循环？

我尝试发送一个包含'exit‘的字符串，将发送的值读入my_input并在tok2.py中中断循环。

现在tok2永远在运行。

使用Debian 10 Buster和Python 3.7。

tok1.py：

import sys
import time
import subprocess

command = [sys.executable, 'tok2.py']
proc = subprocess.Popen(command, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)

i=0
while proc.poll() is None:
    if i > 5:
        #Send 'exit' after 5th iteration
        proc.stdin.write(b'exit')

    print('tok1: '  + str(i))

    time.sleep(0.5)
    i=i+1

tok2.py：

import sys
import time

ii=0
my_input =''
while True:
    my_input = sys.stdin.read()

    if my_input == b'exit':
        print('tok2: exiting')
        sys.stdout.flush()
        break

    print('tok2: ' + str(ii))
    sys.stdout.flush()
    ii=ii+1    
    time.sleep(0.5)

Answer 1

您可以简单地调用proc.terminate()来终止tok2.py进程，这在逻辑上等同于终止循环。

Answer 2

由于下面的答案可能不会被视为“优雅”退出，您还可以设置一个环境变量并检查它。

tok1.py

import sys
import time
import subprocess
import os

command = [sys.executable, 'tok2.py']
proc = subprocess.Popen(command, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)

i=0
while proc.poll() is None:
    if i > 5:
        #Set 'exit' to 'true' after 5th iteration
        os.environ["EXIT"] = "true"
        proc.terminate()

    print('tok1: '  + str(i))

    time.sleep(0.5)
    i=i+1

tok2.py

import sys 
import time
import os

ii=0
my_input ='' 
while True:
    my_input = sys.stdin.read()

    if os.environ['EXIT'] == "true":
        print('tok2: exiting')
        sys.stdout.flush()
        break

    print('tok2: ' + str(ii))
    sys.stdout.flush()
    ii=ii+1
    time.sleep(0.5)