manpreet Best Answer 2 years ago

I am sorry if this is a stupid question but this has been bugging me for the last 2 weeks and I had to finally ask. I am trying to listen to redis publish s://forum.tuteehub.com/tag/messages">messages that I send from Node JS express in Python. I see that 2 things are possible

1. I can either have a simple thread run infinitely and call join inside the main thread which means that the main thread will end only when the thread ends. But I have an infinite thread so seems like a cheat code
2. I can set the Thread as Daemon and run infinitely but main thread also needs to run infinitely in order to receive events such as KeyboardInterrupt
3. Can someone kindly explain WHICH approach is better? and WHATS the DIFFERENCE
4. I am looking to run this Python process infinitely along with my node express from where I publish s://forum.tuteehub.com/tag/messages">messages with redis and Python receives them in order to do some numpy computations

Common parts

import redis
import threading
import time

client = redis.Redis()
subscriber = client.pubsub()
subscriber.subscribe("klines")

Method 1

class ThreadedSubscriber1(threading.Thread):
"""
This class handles subscription s://forum.tuteehub.com/tag/messages">messages from redis inside a separate thread in its run() s://forum.tuteehub.com/tag/method">method
"""
def __init__(self):
super().__init__()

def run(self):
for message in subscriber.listen():
print(message)

def main1():
try:
s = ThreadedSubscriber1()
s.start()
s.join()
except KeyboardInterrupt:
pass

main1()

Method 2

class ThreadedSubscriber2(threading.Thread):
"""
This class handles subscription s://forum.tuteehub.com/tag/messages">messages from redis inside a separate thread in its run() s://forum.tuteehub.com/tag/method">method
"""

def __init__(self):
super().__init__()

def run(self):
for message in subscriber.listen():
print(message)

def main2():
try:
s = ThreadedSubscriber2()
s.setDaemon(True)
s.start()

while True:
time.sleep(1)
except KeyboardInterrupt:
pass

main2()