python fcntl文件锁

pid.py

import fcntl
import time


pidfile = "1.pid"

with open(pidfile, "w") as f:
    try:
        fcntl.flock(f, fcntl.LOCK_EX | fcntl.LOCK_NB)

        while True:
            print("hello")
            time.sleep(5)
    except BlockingIOError:
        print("already running, quit!")