subprocess与子进程交互

1.readline存在阻塞机制，启动线程监控

2.检测到exit、quit，终止process子进程-》终止进程完成会关闭stdout、stderr-》关闭后pipe.readline返回''-》子线程跳出循环结束

import subprocess
import threading
import time


def read_output(pipe):
    try:
        for line in iter(pipe.readline, ''):
            if not line:
                break
            print(line, end='')
    finally:
        pipe.close()

process = subprocess.Popen(
    ["python","-i"],
    stdin=subprocess.PIPE,
    stdout=subprocess.PIPE,
    stderr=subprocess.PIPE,
    text=True,
    bufsize=1
)

# 启动线程
threads = [
    threading.Thread(target=read_output, args=(process.stdout,)),
    threading.Thread(target=read_output, args=(process.stderr,))
]

for t in threads:
    t.start()

try:
    while True:
        cmd = input(">>> ")
        if cmd.strip().lower() in ("exit", "quit"):
            break
        process.stdin.write(cmd + "\n")
        process.stdin.flush()
        time.sleep(0.001)

except KeyboardInterrupt:
    print("Interrupted")

finally:
    process.terminate()

    try:
        process.wait(timeout=5)
    except subprocess.TimeoutExpired:
        process.kill()

    # 关闭 stdin
    if process.stdin:
        process.stdin.close()

    # 等线程退出
    for t in threads:
        t.join(timeout=2)

    print("Process closed")