SimpleQueue use differs across python versions

[davidp1404]

Things to check first

• I have checked that my issue does not already have a solution in the FAQ

• I have searched the existing issues and didn't find my bug already reported there

• I have checked that my bug is still present in the latest release

Version

APScheduler==3.10.4

What happened?

Using this simple code:

import asyncio
from multiprocessing import SimpleQueue, set_start_method
from apscheduler.executors.pool import ThreadPoolExecutor, ProcessPoolExecutor
from apscheduler.schedulers.background import BackgroundScheduler
from random import random
import time
import uuid
from confluent_kafka import Consumer, KafkaException


# Function to be run as a daemon
def daemon_task_1(**kwargs):
    print("Daemon Task 1 is running")
    while True:
        queue.put(random())

def daemon_task_2(**kwargs):
    print("Daemon Task 2 is running")
    while True:
        data = queue.get()
        print(data)


def main():
    executors = {
        'default': ProcessPoolExecutor(max_workers=8,)
    }
    job_defaults = {
        'coalesce': False,
        'max_instances': 3,
        'misfire_grace_time': None
    }    
    # Scheduler for the daemon tasks
    scheduler = BackgroundScheduler(
        executors=executors,
        job_defaults=job_defaults,
        daemonic=True,
        daemon=True
    )
    
    scheduler.add_job(daemon_task_1, trigger='date')
    scheduler.add_job(daemon_task_2, trigger='date')

    global queue
    queue = SimpleQueue()
    # Start the scheduler
    scheduler.start()

    try:
        while True:
            time.sleep(1)
    except (KeyboardInterrupt, SystemExit):
        pass
    finally:
        scheduler.shutdown()

if __name__ == '__main__':
    main()

When I run it with python 3.8 it works fine:

$ python -V;python aps-mixed.py | more
Python 3.8.18
Daemon Task 2 is running
0.7147972065089533
0.9088275181513735
0.770493801418164
0.0914193457803868
0.7720603694858935
0.48302319930441084
...

But with 3.11 I get this error, why?

Python 3.11.11
Job "daemon_task_1 (trigger: date[2025-01-29 16:47:01 CET], next run at: 2025-01-29 16:47:01 CET)" raised an exception
Traceback (most recent call last):
  File "/home/davidp/.pyenv/versions/mlserver2/lib/python3.11/site-packages/apscheduler/executors/base.py", line 131, in run_job
    retval = job.func(*job.args, **job.kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/davidp/gitlab/geoapps-ta-study/kafka/aps-mixed.py", line 15, in daemon_task_1
    queue.put(random())
    ^^^^^
NameError: name 'queue' is not defined
Job "daemon_task_2 (trigger: date[2025-01-29 16:47:01 CET], next run at: 2025-01-29 16:47:01 CET)" raised an exception
Traceback (most recent call last):
  File "/home/davidp/.pyenv/versions/mlserver2/lib/python3.11/site-packages/apscheduler/executors/base.py", line 131, in run_job
    retval = job.func(*job.args, **job.kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/davidp/gitlab/geoapps-ta-study/kafka/aps-mixed.py", line 20, in daemon_task_2
    data = queue.get()
           ^^^^^
NameError: name 'queue' is not defined

How can we reproduce the bug?

Already described in the issue