a control loop keeping several threads alive

README

virtualenv -p $(which python3) venv
source venv/bin/activate
    
(venv)[klang@ergates workers]$ python -i tester_run.py
>>>

tester.log

looper:08:44:15 - limited-2 initializing
looper:08:44:15 - limited-5 initializing
looper:08:44:16 - limited-4 initializing
looper:08:44:16 - another-2 initializing
looper:08:44:16 - another-1 initializing
looper:08:44:16 - limited-3 initializing
looper:08:44:17 - limited-1 initializing
looper:08:44:18 - limited-2 starting up
limited-2:08:44:18 - 1
looper:08:44:18 - limited-5 starting up
limited-5:08:44:18 - 1
looper:08:44:18 - limited-4 starting up
limited-4:08:44:18 - 1
looper:08:44:19 - another-2 starting up
another-2:08:44:19 - 1
looper:08:44:19 - another-1 starting up
another-1:08:44:19 - 1
looper:08:44:19 - limited-3 starting up
limited-3:08:44:19 - 1
looper:08:44:19 - limited-1 starting up
limited-1:08:44:19 - 1
another-2:08:44:21 - 2
another-1:08:44:21 - 2
another-2:08:44:23 - 3
limited-2:08:44:23 - 2
another-1:08:44:23 - 3
limited-5:08:44:23 - 2
limited-4:08:44:23 - 2
limited-3:08:44:24 - 2
limited-1:08:44:24 - 2
another-2:08:44:25 - 4
another-1:08:44:25 - 4
another-2:08:44:27 - 5
another-1:08:44:27 - 5
limited-2:08:44:28 - 3
limited-5:08:44:28 - 3
limited-4:08:44:28 - 3
limited-3:08:44:29 - 3
limited-1:08:44:29 - 3
looper:08:44:30 - another-2 initializing
looper:08:44:30 - another-1 initializing
looper:08:44:33 - another-2 starting up
another-2:08:44:33 - 1
looper:08:44:33 - another-1 starting up
another-1:08:44:33 - 1
limited-2:08:44:33 - 4
limited-5:08:44:33 - 4
limited-4:08:44:33 - 4
limited-3:08:44:34 - 4
limited-1:08:44:34 - 4
another-2:08:44:35 - 2
another-1:08:44:35 - 2
another-2:08:44:37 - 3
another-1:08:44:37 - 3
limited-2:08:44:38 - 5
limited-5:08:44:38 - 5
limited-4:08:44:38 - 5
another-2:08:44:39 - 4
another-1:08:44:39 - 4
limited-3:08:44:39 - 5
limited-1:08:44:39 - 5
another-2:08:44:41 - 5
another-1:08:44:41 - 5
looper:08:44:44 - another-2 initializing
looper:08:44:44 - another-1 initializing
looper:08:44:46 - limited-2 initializing
looper:08:44:46 - limited-5 initializing
looper:08:44:46 - limited-4 initializing
looper:08:44:46 - another-2 starting up
another-2:08:44:46 - 1
looper:08:44:47 - another-1 starting up
another-1:08:44:47 - 1
looper:08:44:47 - limited-3 initializing
looper:08:44:47 - limited-1 initializing
another-2:08:44:48 - 2
looper:08:44:48 - limited-2 starting up
limited-2:08:44:48 - 1
another-1:08:44:49 - 2
looper:08:44:49 - limited-5 starting up
limited-5:08:44:49 - 1
looper:08:44:49 - limited-4 starting up
limited-4:08:44:49 - 1
looper:08:44:50 - limited-3 starting up
limited-3:08:44:50 - 1
looper:08:44:50 - limited-1 starting up
limited-1:08:44:50 - 1
another-2:08:44:50 - 3
another-1:08:44:51 - 3

tester.py

import logging, time

def startLimited():
    count = 1
    for i in range(5):
        logging.info(time.strftime("%H:%M:%S") + " - " + str(count))
        count = count + 1
        time.sleep(3)

def startAnother():
    count = 1
    for i in range(5):
        logging.info(time.strftime("%H:%M:%S") + " - " + str(count))
        count = count + 1
        time.sleep(2)

tester_run.py

import threading,time,logging, tester

logging.basicConfig(filename='tester.log',level=logging.INFO, format="%(threadName)s:%(message)s")

threads = {"limited-1": None,
           "limited-2": None,
           "limited-3": None,
           "limited-4": None,
           "limited-5": None,
           "another-1": None,
           "another-2": None}

def startThread(name):
    threadType = name.split("-")[0]
    newThread = None
    if threadType == "limited":
        newThread = threading.Thread(target=tester.startLimited, name=name, daemon=True)
    elif threadType == "another":
        newThread = threading.Thread(target=tester.startAnother, name=name, daemon=True)
    return newThread

def loopylooper():     
    while 1:
       for name,thread in threads.items():
           # if the thread isn't initialized yet or has died
           if thread == None or thread._started.isSet() and not thread.isAlive():
               logging.info(time.strftime("%H:%M:%S") + " - " + name + " initializing")
               threads[name] = startThread(name)
           # if the thread has never been started, start it.
           if not thread == None and not thread._started.isSet() and not thread.isAlive():
               logging.info(time.strftime("%H:%M:%S") + " - " + name + " starting up")
               thread.start()
           time.sleep(0.25)
       time.sleep(1)

looper=threading.Thread(target=loopylooper, name="looper", daemon=True)

looper.start()