Async/Await Fundamentals: Non-Blocking Python

Learning Objectives: After this lesson, you'll understand event loops and coroutines, write async code with asyncio, handle concurrent I/O operations, and build async patterns for production applications.

Understanding Async Programming

Async programming allows handling many I/O operations concurrently without threads. Let's visualize the event loop:

The event loop runs coroutines one at a time. When one hits await, it pauses and another can run. This is cooperative multitasking.

The Problem with Blocking I/O

Async Solution Preview

Coroutines and async def

await Keyword

Concurrent Execution

asyncio.gather - Run Multiple Coroutines

asyncio.create_task - Background Tasks

asyncio.wait - Advanced Control

asyncio.as_completed - Process as They Finish

Error Handling

Timeouts and Cancellation

Async Context Managers and Iterators

Async Generators

Practical Patterns

Semaphore - Rate Limiting

Queue-based Worker Pool

Async HTTP Requests (aiohttp pattern)

Practice Exercises

Exercise 1: Async Retry with Backoff

Exercise 2: Async Resource Pool

Key Takeaways

When to Use Async

Next Steps

In the next lesson, we'll explore Testing Best Practices—master pytest with fixtures, parametrization, and mocking, learn TDD, and write maintainable tests.

Ready to write bulletproof code? Testing awaits!