Python threading get_ident Function

The threading.get_ident function in Python's threading module returns the "thread identifier" of the current thread. This identifier is a non-zero integer that uniquely identifies each thread during its lifetime. It can be useful for debugging and logging purposes.

Table of Contents

1. Introduction
2. threading.get_ident Function Syntax
3. Examples
   • Basic Usage
   • Using with Thread Creation
   • Comparing Thread Identifiers
4. Real-World Use Case
5. Conclusion

Introduction

The threading.get_ident function provides a unique identifier for the current thread. This can be useful for tracking threads and distinguishing between them, especially when debugging or logging thread activity.

threading.get_ident Function Syntax

Here is how you use the threading.get_ident function:

import threading

thread_id = threading.get_ident()

Returns:

• A non-zero integer representing the unique identifier of the current thread.

Examples

Basic Usage

Get and print the identifier of the current thread.

Example

import threading

def worker():
    thread_id = threading.get_ident()
    print(f"Worker thread ID: {thread_id}")

worker_thread = threading.Thread(target=worker)
worker_thread.start()
worker_thread.join()

main_thread_id = threading.get_ident()
print(f"Main thread ID: {main_thread_id}")

Output:

Worker thread ID: 123145321082368
Main thread ID: 140735282373568

Using with Thread Creation

Track the identifiers of multiple threads.

Example

import threading

def worker():
    thread_id = threading.get_ident()
    print(f"Worker thread ID: {thread_id}")

threads = []
for i in range(3):
    thread = threading.Thread(target=worker)
    threads.append(thread)
    thread.start()

for thread in threads:
    thread.join()

main_thread_id = threading.get_ident()
print(f"Main thread ID: {main_thread_id}")

Output:

Worker thread ID: 123145321082368
Worker thread ID: 123145321082368
Worker thread ID: 123145321082368
Main thread ID: 140735282373568

Comparing Thread Identifiers

Compare the identifiers of the current thread and the main thread.

Example

import threading

def worker():
    worker_thread_id = threading.get_ident()
    main_thread_id = threading.main_thread().ident
    if worker_thread_id == main_thread_id:
        print("Worker is running on the main thread")
    else:
        print("Worker is running on a worker thread")

worker_thread = threading.Thread(target=worker)
worker_thread.start()
worker_thread.join()

main_thread_id = threading.get_ident()
print(f"Main thread ID: {main_thread_id}")

Output:

Worker is running on a worker thread
Main thread ID: 140735282373568

Real-World Use Case

Logging Thread Activity

Use threading.get_ident to log the activity of different threads.

Example

import threading
import logging

logging.basicConfig(level=logging.DEBUG, format='%(asctime)s %(message)s')

def worker():
    thread_id = threading.get_ident()
    logging.debug(f"Worker thread ID: {thread_id} is running")
    logging.debug(f"Worker thread ID: {thread_id} is doing some work")
    logging.debug(f"Worker thread ID: {thread_id} has finished work")

threads = []
for i in range(3):
    thread = threading.Thread(target=worker)
    threads.append(thread)
    thread.start()

for thread in threads:
    thread.join()

main_thread_id = threading.get_ident()
logging.debug(f"Main thread ID: {main_thread_id} is exiting")

Output:

2023-07-25 12:00:00,000 Worker thread ID: 123145321082368 is running
2023-07-25 12:00:00,001 Worker thread ID: 123145321082368 is doing some work
2023-07-25 12:00:00,002 Worker thread ID: 123145321082368 has finished work
2023-07-25 12:00:00,003 Worker thread ID: 123145321082368 is running
2023-07-25 12:00:00,004 Worker thread ID: 123145321082368 is doing some work
2023-07-25 12:00:00,005 Worker thread ID: 123145321082368 has finished work
2023-07-25 12:00:00,006 Worker thread ID: 123145321082368 is running
2023-07-25 12:00:00,007 Worker thread ID: 123145321082368 is doing some work
2023-07-25 12:00:00,008 Worker thread ID: 123145321082368 has finished work
2023-07-25 12:00:00,009 Main thread ID: 140735282373568 is exiting

Conclusion

The threading.get_ident function is used for obtaining the unique identifier of the current thread in Python. It can be used for debugging, logging, and tracking thread activity, providing a clear way to distinguish between different threads in your application. Proper usage can enhance the visibility and manageability of your multithreaded programs.