How to kill a thread through console inputs

Question

I would like to have a thread running indefinitely, and have a „user interface“ (console command) by which I can stop a thread from running. How would I go about this?

import threading
from time import sleep

class Counter() :

  index = 0       

  def __init__(self,offset) :

    self.n = 0                            
    self.offset = offset              
    self.nr = Counter.index       
    Counter.index = Counter.index + 1  
    self.bool = True
  def start(self) :                 

    def commence() :
      while self.bool :
        print(str(self.nr)+": "+str(self.n))  
        self.n = self.n + 1                   
        sleep(self.offset)   
    
    threading.Thread(target=commence,args=()).start()  
    
    
Counter(1).start()

Answer 1

Here's one way to do this:

import threading
from time import sleep


class Counter:

    index = 0

    def __init__(self, offset):
        self.n = 0
        self.offset = offset
        self.nr = Counter.index
        Counter.index = Counter.index + 1
        self.lock = threading.Lock()
        self.bool = True
          

    def start(self):
        def commence():
            while True:
                with self.lock:
                    if self.bool == False:
                        break
                print(str(self.nr)+": "+str(self.n))
                self.n = self.n + 1
                sleep(self.offset)

        thr = threading.Thread(target=commence, args=())
        thr.start()
        input("Please hit ENTER key to stop counter")
        with self.lock:
            self.bool = False
        thr.join()


Counter(1).start()

Here's an example to deal with multiple counters.

import threading
from time import sleep


class Counter(threading.Thread):

    index = 0

    def __init__(self, offset):
        super().__init__()
        self.n = 0
        self.offset = offset
        self.nr = Counter.index
        Counter.index = Counter.index + 1
        self.lock = threading.Lock()
        self.bool = True

    def stop(self):
        with self.lock:
            self.bool = False
        self.join()

    def run(self):
        while True:
            with self.lock:
                if self.bool == False:
                    break
            print(f"Counter offset {self.offset} {self.nr}:{self.n}")
            self.n = self.n + 1
            sleep(max(self.offset, 1))

        

num_counters = 3
counters = []
for i in range(num_counters):
    counter = Counter(i)
    counter.start()
    counters.append(counter)

counters_stopped = 0
while counters_stopped < num_counters:
    counter_to_kill = int(input("Enter the counter offset to kill"))
    the_counter = counters[counter_to_kill]
    counters[counter_to_kill] = None
    the_counter.stop()
    counters_stopped += 1
    print(f'Stopped counter at offset {counter_to_kill}')
print("All counters stopped")