Timeout the function after certain time

Question

I have a long-running thread which calls a method. I want to implement a timeout for a method which takes more than a certain time and exit the method but not thread.

Note: My use case is(Objective), I have a thread which continuously polls from a real-time data stream and process it with some method(which might end up taking infinite time for certain data point). So I want to timeout the method but not thread so that I can keep polling the real-time data.

Below is the sample code which I'm trying to fix it. It works when we start a single thread and an exception is created but with more than 1 thread signal doesn't work.

from threading import Thread
import time
import signal

def random_func(a):
    time.sleep(a)
    return True


class TimeoutException(Exception):   # Custom exception class
    pass

def timeout_handler(signum, frame):   # Custom signal handler
    raise TimeoutException

signal.signal(signal.SIGALRM, timeout_handler)
class CheckThreadSignal(Thread):
    def __init__(self, thread_id):
        self.thread_id = thread_id
        super().__init__()
    def run(self):
        c = 0
        while True:
            signal.alarm(5)
            try:
                if self.thread_id == 2 and c == 10:
                    random_func(10)
                else:
                    random_func(0.1)
            except TimeoutException:
                print("signal: {}".format(self.thread_id), e)
                continue
            else:
                signal.alarm(0)
                print("running: {}, count: {}".format(self.thread_id, c))
                time.sleep(0.1)
                c+=1
                
CheckThreadSignal(0).start()
CheckThreadSignal(2).start()