cofollow.py

# cofollow.py
import os
import time
import csv

def follow(filename,target):
    with open(filename,"r") as f:
        f.seek(0,os.SEEK_END)
        while True:
            line = f.readline()
            if line != '':
                target.send(line)
            else:
                time.sleep(0.1)

# Decorator for coroutines
from functools import wraps

def consumer(func):
    @wraps(func)
    def start(*args,**kwargs):
        f = func(*args,**kwargs)
        f.send(None)
        return f
    return start

# Sample coroutine
@consumer
def printer():
    while True:
        try:
            item = yield
            print(item)
        except Exception as e:
            print('ERROR: %r' % e)

# Example use.  

if __name__ == '__main__':
    follow('../../Data/stocklog.csv', printer())