tail.py

#!/usr/bin/env python3
import subprocess
import threading
from queue import Queue

tailq = Queue(maxsize=10)

def tail(filename):
    p = subprocess.Popen(
        ['tail', '-f', filename],  # args
        stdout=subprocess.PIPE,
    )
    while True:
        line = p.stdout.readline()
        tailq.put(line)
        if not line:
            break


if __name__ == '__main__':
    threading.Thread(target=tail, args=('sample.txt',)).start()
    while True:
        print(tailq.get())  # block
        # print(tailq.get_nowait())  # non-block