Thread-safe Queue in Python

As the demand for efficient and scalable applications grows, there is a need to develop robust programs that can handle multiple threads effectively. One of the ways to achieve this is through the use of a thread-safe queue. In this tutorial, we will explore the concept of thread-safe queues in Python and how they can be used to manage multiple threads concurrently while preventing data corruption and race conditions. We will examine the Python built-in queue module and demonstrate how to create, manipulate, and access thread-safe queues.

Python Thread-Safe Queue :

• A thread-safe queue in Python is a data structure that can be used to communicate between multiple threads and ensure that data is being shared safely.
• The queue module in Python provides a Queue class that is thread-safe and can be used to implement a thread-safe queue.

Different Queue Operations :

• Different operations that we can perform on the queue are - 
  • Creating a New Queue in python
  • Adding a new Item to the Queue
  • Fetch an Item from the Queue
  • Getting the Size of the Queue

Creating a New Queue in python

• To create a new queue, you can simply create a new instance of the  Queue   class from the  queue  module.
• Code Sample : 

from queue import Queue

# Create a new queue
q = Queue()

Adding a new Item to the Queue :

• To add an item to the queue, use the  put()  method.
• Code Sample : 

# Add an item to the queue
q.put(item)

Fetch an Item from the Queue :

• To get an item from the queue, use the  get()  method. 
• This method will block until an item is available in the queue.
• Code Sample : 

# Get an item from the queue
item = q.get()

Getting the Size of the Queue :

• To get the size of the queue, use the  qsize()  method.
• Code Sample : 

# Get the size of the queue
size = q.qsize()

Marking a Task as Completed :

• To mark a task as completed, use the  task_done()  method.
• Code Sample : 

# Mark a task as completed
q.task_done()

Waiting for All Tasks on the Queue to be Completed :

• To wait for all tasks on the queue to be completed, use the  join()  method.
• Code Sample : 

# Wait for all tasks on the queue to be completed
q.join()

Implementing Python Thread-Safe Queue :

• Here, we create a thread-safe queue q and 5 worker threads using the worker() function as their target.
• We add  10  items to the queue using put(), then wait for all tasks to be completed using  join() .
• We then stop the worker threads by adding None items to the queue and waiting for the threads to finish using   join() .
• Code Sample : 

import threading
import queue

def worker(q):
   while True:
       item = q.get()
       if item is None:
           break
       print("Processing item", item)
       q.task_done()

# Create a queue and worker threads
q = queue.Queue()
threads = []
for i in range(5):
   t = threading.Thread(target=worker, args=(q,))
   t.start()
   threads.append(t)

# Add items to the queue
for item in range(10):
   q.put(item)

# Wait for all tasks on the queue to be completed
q.join()

# Stop worker threads
for i in range(5):
   q.put(None)
for t in threads:
   t.join()