Example of queueing / de-queing in Python

q_dq_example.py

import threading, queue                                                                                                                                        
import random                                                                                                                                                  
import time                                                                                                                                                    

'''
Representaive output 

$ python queue_example.py 

> Submission of 0 pausing for 3
< Processing of 0 pausing for 2
< Working on 0
< Finished 0
> Submission of 1 pausing for 3
< Processing of 1 pausing for 1
< Working on 1
< Finished 1
> Submission of 2 pausing for 1
> Submission of 3 pausing for 0
< Processing of 2 pausing for 0
< Working on 2
< Finished 2
> Submission of 4 pausing for 2
< Processing of 3 pausing for 3
< Working on 3
< Finished 3
> Submission of 5 pausing for 1
< Processing of 4 pausing for 1
< Working on 4
< Finished 4
< Processing of 5 pausing for 0
< Working on 5
< Finished 5
> Submission of 6 pausing for 1
< Processing of 6 pausing for 1
< Working on 6
< Finished 6
> Submission of 7 pausing for 3
> Submission of 8 pausing for 0
< Processing of 7 pausing for 3
< Working on 7
< Finished 7
< Processing of 8 pausing for 3
< Working on 8
< Finished 8
All work completed


'''
q = queue.Queue()                                                                                                                                              
                                                                                                                                                               
def worker():                                                                                                                                                  
    while True:                                                                                                                                                
        processing_delay = random.randint(0, 3)                                                                                                                
        time.sleep(processing_delay)                                                                                                                           
        item = q.get()                                                                                                                                         
        print(f'< Processing of {item} pausing for {processing_delay}')                                                                                        
        print(f'< Working on {item}')                                                                                                                          
        print(f'< Finished {item}')                                                                                                                            
        q.task_done()                                                                                                                                          
                                                                                                                                                               
# Turn-on the worker thread.                                                                                                                                   
threading.Thread(target=worker, daemon=True).start()                                                                                                           
                                                                                                                                                               
# Send thirty task requests to the worker.                                                                                                                     
for item in range(9):                                                                                                                                          
    submission_delay = random.randint(0, 3)                                                                                                                    
    time.sleep(submission_delay)                                                                                                                               
    print(f'> Submission of {item} pausing for {submission_delay}')                                                                                            
    q.put(item)                                                                                                                                                
                                                                                                                                                               
# Block until all tasks are done.                                                                                                                              
q.join()                                                                                                                                                       
print('All work completed')