test.py

import logging
from logging import handlers
import os
import random
import threading
import time


script_dir = os.path.dirname(os.path.realpath(__file__))
log_filename = os.path.join(script_dir, "test.log")
handler = handlers.TimedRotatingFileHandler(
    filename=log_filename, when="midnight", utc=True
)

logging.basicConfig(
    level=logging.INFO,
    format="%(levelname)-8s [%(asctime)s] %(threadName)-16s: %(message)s",
    #handlers=[handler],
)

logger = logging.getLogger(__name__)


global_number = 1


def worker(condition):
    while True:
        with condition:
            logger.debug("acquired condition lock")
            #while global_number != 10:
            if global_number != 10:  # <--- incorrect!
                logger.info("the number is not 10, will wait for condition")
                condition.wait()
            #condition.wait_for(lambda: global_number == 10)  # <--- alternative
            logger.info(f"I see the number {global_number}")
            logger.debug("releasing condition lock")
        time.sleep(1)


def number_changer(condition):
    global global_number
    while True:
        with condition:
            logger.debug("acquired condition lock")
            new_number = random.randint(1, 10)
            logger.info(f"Changing number from {global_number:>2} to {new_number:>2}")
            global_number = new_number
            if new_number == 10:
                logger.info("New number == 10, notifying others")
                condition.notify_all()
            logger.debug("releasing condition lock")
        time.sleep(1)


def main():
    logger.info("main() started")
    number_eq_10 = threading.Condition()
    
    worker_thread = threading.Thread(
        name="Thread-Worker",
        target=worker,
        args=(number_eq_10,),
        daemon=True,
    )

    changer_threads = [
        threading.Thread(
            name=f"Thread-Changer-{i}",
            target=number_changer,
            args=(number_eq_10,),
            daemon=True,
        )
        for i in range(5)
    ]

    worker_thread.start()
    for t in changer_threads:
        t.start()

    while True:
        try:
            time.sleep(60)
        except KeyboardInterrupt:
            logger.info("Main thread exiting")
            break
    _


if __name__ == "__main__":
    main()

Excellent code+explanation. Took me a while but I get it now. Thank you!