Python signals: ValueError: signal only works in main thread

Question

I have this python code:

from pytchat import LiveChat
import time
import requests
import threading

video_id = None
liveChat = None

def runChat():
  global liveChat
  liveChat = LiveChat(video_id)
  while liveChat.is_alive():
    try:
      chatdata = liveChat.get()
      for c in chatdata.items:
          print(f"{c.datetime} [{c.author.channelId}]- {c.message}")
          chatdata.tick()
    except KeyboardInterrupt:
      liveChat.terminate()
      break

def checkId():
  threading.Timer(1.0, checkId).start()
  global video_id
  req = requests.get("http://localhost/getId")
  if req.status_code == 200:
    vidId = req.text
    if vidId != "null" and vidId != video_id:
        video_id = vidId
        print(f"got id: {video_id}")
        if liveChat is not None:
          liveChat.terminate()
        runChat()

def main():
  checkId()

if __name__ == '__main__':
  main()

That utilizes the pytchat library (https://github.com/taizan-hokuto/pytchat).
As you can see, I want to dynamically change the videoId that the chat is bundled to, but with the code above this is the result:

root@vps:~# python3 liveChat.py
got id: a10TAdVZmOq # First id, the library works, we can capture chat messages.
got id: NMre6IAPoLI # After second id appears, there is this exception:
Exception in thread Thread-52:
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/threading.py", line 916, in _bootstrap_inner
    self.run()
  File "/usr/local/lib/python3.6/threading.py", line 1182, in run
    self.function(*self.args, **self.kwargs)
  File "liveChat.py", line 36, in checkId
    runChat()
  File "liveChat.py", line 11, in runChat
    liveChat = LiveChat(video_id)
  File "/usr/local/lib/python3.6/site-packages/pytchat/core_multithread/livechat.py", line 110, in __init__
    signal.signal(signal.SIGINT, lambda a, b: self.terminate())
  File "/usr/local/lib/python3.6/signal.py", line 47, in signal
    handler = _signal.signal(_enum_to_int(signalnum), _enum_to_int(handler))
ValueError: signal only works in main thread

How can this be solved since signals only work in main thread?

Asked By: AnB

||

Source

Answer 1

Adding the parameter interruptable=False to the LiveChat object solved the issue.

def runChat():
  global liveChat
  liveChat = LiveChat(video_id, interruptable=False)  #  <---THIS
  while liveChat.is_alive():
  # ....

https://github.com/taizan-hokuto/pytchat/issues/8

Answered By: AnB

Answer 2

Excellent Thanks for the fix!
I was running into this same issue trying to set up a program..

I am using pytchat as well but not the ‘livechat’ portion but instead mine is as follows..
chat = pytchat.create(video_id="jfKfPfyJRdk", interruptable=False)

but i did not have interupptable=false until i came across this post which solved my issue

Answered By: Gitago Gaming

Python signals: ValueError: signal only works in main thread

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