Python中process.kill()无法终止目标进程的问题排查

你使用了shell=True，此时subprocess.Popen启动的是shell进程，而你的目标程序./Process是这个shell的子进程。调用process.kill()只会终止shell进程，但它的子进程会变成孤儿进程被系统接管，继续运行，所以你看不到进程被终止的效果。

方案1：移除shell=True（推荐） #

直接启动目标进程，不需要通过shell中转，这样process就是./Process本身，kill()能直接终止它：

def monitor_process(process, file):
    while True:
        outline = process.stdout.readline().decode()
        if not outline:  # 进程退出时readline返回空字符串，终止循环
            break
        file.write(outline)
        file.flush()
        if "error" in outline:
            file.write("stdout: Error encountered. Exiting process.\n")
            file.flush()
            process.kill()
            break

def runProcess(flight_path):
    output_file = flight_path + "/Process_terminal.log"
    with open(output_file, "w") as file:
        os.chdir("./build")
        # 去掉shell=True，用列表形式传入命令
        process = subprocess.Popen(["./Process"], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
        output_thread = threading.Thread(target=monitor_process, args=(process, file))
        output_thread.start()
        process.wait()  
        output_thread.join()

方案2：保留shell=True时杀掉整个进程组 #

如果必须用shell（比如需要shell的管道、通配符等特性），需要杀掉shell所在的整个进程组，确保子进程也被终止：

import os
import signal

def monitor_process(process, file):
    while True:
        outline = process.stdout.readline().decode()
        if not outline:
            break
        file.write(outline)
        file.flush()
        if "error" in outline:
            file.write("stdout: Error encountered. Exiting process.\n")
            file.flush()
            try:
                # 获取进程组ID，杀掉整个组
                os.killpg(os.getpgid(process.pid), signal.SIGKILL)
            except ProcessLookupError:
                # 进程可能已经退出，忽略异常
                pass
            break

def runProcess(flight_path):
    output_file = flight_path + "/Process_terminal.log"
    with open(output_file, "w") as file:
        os.chdir("./build")
        command = "./Process"
        process = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
        output_thread = threading.Thread(target=monitor_process, args=(process, file))
        output_thread.start()
        process.wait()  
        output_thread.join()

• 原代码中if process.stdout:判断多余，因为你已经指定了stdout=subprocess.PIPE，process.stdout必然存在
• 可以把"error"判断改成大小写不敏感的"error" in outline.lower()，避免漏判大写的ERROR
• os.chdir("./build")如果目录不存在会报错，建议提前检查目录是否存在：if not os.path.exists("./build"): raise FileNotFoundError("Build directory not found")

内容的提问来源于stack exchange，提问作者MsA