Python threading Timer callback example

python_thread_test.py

import time
import threading

ser = 0
start_time = time.time()

def callback():
    global ser, start_time

    if ser == 1:
        print("Open {}, {}".format(time.time() - start_time, ser))
        ser = 2

    elif ser == 2:
        print("thread started {}, {}".format(time.time() - start_time, ser))

    else:
        print("OS Error {}, {}".format(time.time(), ser))
        time.sleep(1)
        ser = 1

    threading.Timer(0.1, callback).start()  # run callback in every 0.1 sec
    start_time = time.time()

if __name__=="__main__":
    callback()
    while True:
        time.sleep(1)