Pythonで一定時間ごとに処理を実行する ref: https://qiita.com/kurogelee/items/0e5fd8b6a1d1f169179a

bad.py

import time

def worker():
    print(time.time())
    time.sleep(8)

interval = 5
while True:
    worker()
    time.sleep(interval)

file1.txt

1518294594.6087666
1518294607.611248
1518294620.6149857

file3.txt

>>> schedule(5, worker)
1518295406.8357077
1518295416.849788
1518295426.8451777

file4.txt

>>> schedule(5, worker, False)
1518295478.5527058
1518295483.5534766
1518295488.5580828

schedule.py

import time
import threading

def worker():
    print(time.time())
    time.sleep(8)

def schedule(interval, f, wait=True):
    base_time = time.time()
    next_time = 0
    while True:
        t = threading.Thread(target=f)
        t.start()
        if wait:
            t.join()
        next_time = ((base_time - time.time()) % interval) or interval
        time.sleep(next_time)