6 - Best Practices
Enroll to start learning
Youβve not yet enrolled in this course. Please enroll for free to listen to audio lessons, classroom podcasts and take practice test.
Interactive Audio Lesson
Listen to a student-teacher conversation explaining the topic in a relatable way.
Using asyncio.run()
π Unlock Audio Lesson
Sign up and enroll to listen to this audio lesson
Let's begin by discussing how to start our asynchronous programs effectively. Who can tell me the best function to initiate the main coroutine in Python's asyncio library?
Is it `asyncio.start()`?
Close! The correct function is `asyncio.run()`. This function not only starts our coroutine but also takes care of the event loop's lifecycle.
Why is managing the event loop important, though?
Great question! Proper event loop management is crucial because it allows our asynchronous tasks to run correctly without interference or errors.
Avoiding Blocking Code
π Unlock Audio Lesson
Sign up and enroll to listen to this audio lesson
Now, let's address the importance of avoiding blocking code in async functions. Can someone provide an example of a blocking function?
I think something like `time.sleep()` would be blocking, right?
Exactly! Using `time.sleep()` will halt the execution of our entire program. Instead, we should use `asyncio.sleep()` which allows other tasks to progress while waiting.
What about web requests? Should we use `requests` or is there a better way?
Thatβs an important point! For HTTP operations, we should use `aiohttp` instead of `requests` to keep our code non-blocking.
Awaiting Coroutines
π Unlock Audio Lesson
Sign up and enroll to listen to this audio lesson
Let's delve into the significance of awaiting coroutines. What do you think might happen if we forget to await a coroutine?
It might just not run?
Yes! If we forget to await it, the coroutine is created as a coroutine object but not executed. This could lead to unexpected behavior and outcomes.
So, itβs crucial to always use `await` for functions marked as `async`?
That's correct! Always remember to `await` all async functions to avoid any silent failures.
Introduction & Overview
Read summaries of the section's main ideas at different levels of detail.
Quick Overview
Standard
This section outlines essential best practices for utilizing Python's asyncio library in asynchronous programming, such as starting coroutines with 'asyncio.run()', avoiding mixing blocking code, and leveraging aiohttp for non-blocking HTTP requests. It emphasizes the importance of always awaiting coroutines to prevent silent failures.
Detailed
Best Practices in Asynchronous Programming with asyncio
Asynchronous programming is a powerful mechanism to handle I/O-bound tasks efficiently. In this section, we discuss best practices to ensure effective use of Pythonβs asyncio library:
- Use
asyncio.run(): Always start the main coroutine withasyncio.run()to manage the event loop properly. - Avoid Blocking Code: Mixing blocking functions like
time.sleep()or synchronous network calls in asynchronous code can lead to performance bottlenecks. Instead, use non-blocking alternatives such asaiohttpfor making HTTP requests. - Await All Coroutines: Failing to await coroutines can result in silent skips in execution. Always ensure every coroutine is awaited to avoid unexpected behaviors.
Utilizing these best practices ensures optimal performance and scalability of your asynchronous applications.
Audio Book
Dive deep into the subject with an immersive audiobook experience.
Using asyncio.run()
Chapter 1 of 4
π Unlock Audio Chapter
Sign up and enroll to access the full audio experience
Chapter Content
β Use asyncio.run() to start the main coroutine.
Detailed Explanation
The function asyncio.run() is used to execute the main coroutine within an asyncio program. It handles the creation and management of the event loop automatically. When you call this function, it sets up the loop, runs the specified coroutine until it completes, and then closes the loop when it's done. This makes starting your asynchronous applications much simpler and cleaner.
Examples & Analogies
Think of asyncio.run() as the play director. Just as a director oversees the entire production of a play, ensuring that everything runs smoothly from start to finish, asyncio.run() manages your asynchronous code from beginning to end, allowing the performers (your coroutines) to shine without you having to manage the stage (event loop) manually.
Avoiding Blocking Code
Chapter 2 of 4
π Unlock Audio Chapter
Sign up and enroll to access the full audio experience
Chapter Content
β Avoid mixing blocking code (time.sleep, requests) in async code.
Detailed Explanation
Blocking code, such as time.sleep() or synchronous requests, halts the execution of your program while it waits for a result. This is contrary to the purpose of asynchronous programming, which is to allow other tasks to run concurrently while waiting. To maintain the benefits of asynchronous programming, use async equivalents (like asyncio.sleep() for delays) instead of blocking functions.
Examples & Analogies
Imagine you're cooking a meal. If you have to stand and wait for water to boil (blocking), you cannot prepare the rest of the meal. However, if you set the pot on the stove and then chop vegetables or do another task (async), your cooking becomes much more efficient.
Using aiohttp for HTTP Requests
Chapter 3 of 4
π Unlock Audio Chapter
Sign up and enroll to access the full audio experience
Chapter Content
β Use aiohttp instead of requests for HTTP requests in async code.
Detailed Explanation
When performing HTTP requests in an asynchronous context, itβs important to use a library that supports async operations. Aiohttp is an async HTTP client that allows you to make non-blocking HTTP requests, making your application more efficient. Switching from the synchronous requests library to aiohttp helps maintain the non-blocking nature of your async code.
Examples & Analogies
Think of it like waiting for a bus. If you check the bus schedule through an app that does not support async requests (like requests), you might end up waiting unnecessarily. However, using aiohttp is like having a real-time tracker that lets you know when your bus arrives without stalling your other plans.
Awaiting All Coroutines
Chapter 4 of 4
π Unlock Audio Chapter
Sign up and enroll to access the full audio experience
Chapter Content
β Donβt forget to await all coroutines; failing to do so will silently skip execution.
Detailed Explanation
In asynchronous programming, when you call a coroutine without using await, it does not execute; instead, it simply returns a coroutine object. This could lead to unexpected behavior where some expected code does not run. Itβs essential to use await with every coroutine to ensure they are executed properly and the program behaves as intended.
Examples & Analogies
Imagine you are coordinating a group of friends for a group project. If you ask them to complete tasks but donβt follow up to check if theyβve actually done them (not awaiting), you might end up with unfinished work and confusion about who did what.
Key Concepts
-
Use asyncio.run(): Essential for starting your main coroutine correctly.
-
Avoid blocking code: Implement async-compatible alternatives to prevent halting execution.
-
Always await: Ensure every coroutine is awaited to execute properly.
Examples & Applications
Using asyncio.run(main()) to start your async application.
Replacing time.sleep() with await asyncio.sleep() to create non-blocking pauses.
Memory Aids
Interactive tools to help you remember key concepts
Rhymes
In async code, donβt block the fun, use asyncio.run, let the tasks be done!
Stories
Imagine a chef who must cook several dishes without letting one pot boil over. They can only focus on one dish at a time, but can let others simmer. That's how asyncio.run() manages the kitchen!
Memory Tools
R.A.W. - Remember to Always Await: Always await coroutines to ensure proper execution.
Acronyms
B.A.R. - Block, Await, and Run
Avoid blocking code
Always await functions
use asyncio.run() to execute.
Flash Cards
Glossary
- asyncio
Python's library for writing concurrent code using the async/await syntax.
- async/await
Keywords used to define and manage asynchronous coroutines in Python.
- coroutine
A special function that can pause and resume execution, defined with 'async def'.
- event loop
The core of asyncio which schedules and runs async tasks.
- blocking code
Code that stops further execution until the operation completes, hindering async capabilities.
Reference links
Supplementary resources to enhance your learning experience.