Book Image

Mastering Concurrency in Python

By : Quan Nguyen
Book Image

Mastering Concurrency in Python

By: Quan Nguyen

Overview of this book

Python is one of the most popular programming languages, with numerous libraries and frameworks that facilitate high-performance computing. Concurrency and parallelism in Python are essential when it comes to multiprocessing and multithreading; they behave differently, but their common aim is to reduce the execution time. This book serves as a comprehensive introduction to various advanced concepts in concurrent engineering and programming. Mastering Concurrency in Python starts by introducing the concepts and principles in concurrency, right from Amdahl's Law to multithreading programming, followed by elucidating multiprocessing programming, web scraping, and asynchronous I/O, together with common problems that engineers and programmers face in concurrent programming. Next, the book covers a number of advanced concepts in Python concurrency and how they interact with the Python ecosystem, including the Global Interpreter Lock (GIL). Finally, you'll learn how to solve real-world concurrency problems through examples. By the end of the book, you will have gained extensive theoretical knowledge of concurrency and the ways in which concurrency is supported by the Python language
Table of Contents (22 chapters)

Chapter 4

What is a file descriptor, and in what ways can it be handled in Python?

A file descriptor is used as a handle on an opened external file in a program. In Python, a file descriptor is handled by either using open() and close() functions or using the with statement; for example:

  • f = open(filename, 'r'); ... ; f.close()
  • with open(filename, 'r') as f: ...

What problem arises when file descriptors are not handled carefully?

Systems can only handle a certain number of opened external files in one running process. When that limit is passed, the handles on the opened files will be compromised and file descriptor leakage will occur.

What is a lock, and in what ways can it be handled in Python?

A lock is a mechanism in concurrent and parallel programming that performs thread synchronization. In Python, a threading.Lock object can be handled by either using...