I am creating 2 background schedulers, after the tasks on both the schedulers are started, I am calling scheduler.shutdown(wait=True) but it is not waiting for the tasks to complete, I got around this by having a while loop which check pending jobs using scheduler.get_jobs(), but reading the documentation it should not be required because shutdown(wait=True) is for this purpose, or did I read it wrong.

import time
import os
import random

from apscheduler.schedulers.background import BackgroundScheduler
from apscheduler.executors.pool import ThreadPoolExecutor
from datetime import datetime,timezone,timedelta
from zoneinfo import ZoneInfo

some_data = None # task1() updates it and task2() reads it

def time_now():
    return datetime.now(timezone.utc).astimezone(ZoneInfo('localtime'))
    
def time_now_str():
    return time_now().strftime('%y-%m-%d %H:%M:%S.%f')

def random_int():
    return random.randint(10000000000, 99999999999)

def task1(taskid):
    global some_data
    os.system('/usr/bin/dd if=/dev/zero of=/dev/null bs=10 count=10000 2> /dev/null') ## dummy task
    some_data =random_int()
    print(f'## Task1 ID: {taskid}, Generated some random data = {some_data}, '+time_now_str())
    return some_data

def task2(taskid):
    global some_data
    if some_data is not None:
        curr_data = some_data
        print(f'-- Task2 ID: {taskid}, STARTED task2 for data = {curr_data}: '+time_now_str())
        os.system('/usr/bin/dd if=/dev/zero of=/dev/null bs=10 count=5000000 2> /dev/null') ## dummy task
        print(f'-- Task2 ID: {taskid}, DONE task2 for data = {curr_data}: '+time_now_str())
    else:
        print(f'-- Task2 ID: {taskid}, WARNING, no data yet, looks like task1() has not run yet, '+time_now_str())

        
## main()
 
task1_scheduler = BackgroundScheduler(executors={'default': ThreadPoolExecutor(1)}, job_defaults={'misfire_grace_time': 500, 'coalesce': False})
task2_scheduler = BackgroundScheduler(executors={'default': ThreadPoolExecutor(1)}, job_defaults={'misfire_grace_time': 500, 'coalesce': False})
        
start_time = time_now()

print('Start Time: '+start_time.strftime('%y-%m-%d %H:%M:%S.%f'))

task1_tm = start_time
for idx, interval in enumerate( [1, 8, 14], start=1):
    task1_id = 'task1_id_'+str(idx)
    task1_tm += timedelta(seconds=interval)
    task2_scheduler.add_job(task1,'date',  run_date=task1_tm,  args=[task1_id], id=task1_id, max_instances=1)

task2_tm=start_time
for idx, interval in enumerate([0, 4,19,28], start=1):
    task2_id =  'task2_id_'+str(idx)
    task2_tm += timedelta(seconds=interval)
    task2_scheduler.add_job(task2,'date',  run_date=task2_tm, args=[task2_id], id =task2_id, max_instances=1)

task1_scheduler.start()
task2_scheduler.start()

# I should not need this
while len(task1_scheduler.get_jobs()) > 0 or len(task2_scheduler.get_jobs()) > 0:
    time.sleep(1)

task1_scheduler.shutdown(wait=True)
task2_scheduler.shutdown(wait=True)
    
print(f'Tasks completed: {time_now_str()}n')

OS: Linux Mint 21.2
APScheduler: v3.10.4
Python: v3.10.12