What are the modes of asyncio python ?

Asynchronous programming has become increasingly important in Python for building responsive and scalable applications. The asyncio module introduced in Python 3.4 provides infrastructure for writing asynchronous code using the async/await syntax.

What is Asynchronous Programming?

In synchronous programming, statements execute one after the other, blocking execution until the current statement finishes. Asynchronous programming allows multiple things to happen concurrently without blocking.

Python achieves this through coroutines - functions that can pause execution and yield control back to the event loop. The event loop handles switching between coroutines when they are ready to resume. This allows other coroutines to run while one is waiting on a long running task like fetching data from a web API.

Asyncio Modes of Operation

Asyncio enables asynchronous programming through three main modes:

1. Callbacks

This involves passing callback functions that get executed when the asynchronous operation completes. Callbacks can create complex nested code but are flexible.

import asyncio

def print_text(text):
    print(text)
    
async def main():
   loop = asyncio.get_event_loop()
   loop.call_soon(print_text, "Hello World!")
   
asyncio.run(main())

2. Async/Await

The async/await syntax introduced in Python 3.5 provides a linear execution flow without callbacks. Code reads like synchronous code while behaving asynchronously in the background.

3. Coroutines

Coroutines are async functions that use await to suspend execution while relinquishing control to the event loop. The event loop resumes coroutines when asynchronous operations complete.

Understanding these modes is key to leveraging asyncio for writing asynchronous Python code. Paying attention to blocking calls and using async/await helps avoid common concurrency pitfalls.