Using Asyncio in Python

Preface
Conventions Used in This Book
O’Reilly Online Learning
How to Contact Us
Acknowledgments

1. Introducing Asyncio
The Restaurant of ThreadBots
Epilogue
What Problem Is Asyncio Trying to Solve?

2. The Truth About Threads
Benefits of Threading
Drawbacks of Threading
Case Study: Robots and Cutlery

3. Asyncio Walk-Through
Quickstart
The Tower of Asyncio
Coroutines
The New async def Keywords
The New await Keyword
Event Loop
Tasks and Futures
Create a Task? Ensure a Future? Make Up Your Mind!
Async Context Managers: async with
The contextlib Way
Async Iterators: async for
Simpler Code with Async Generators
Async Comprehensions
Starting Up and Shutting Down (Gracefully!)
What Is the return_exceptions=True for in gather()?
Signals
Waiting for the Executor During Shutdown

4. 20 Asyncio Libraries You Aren’t Using (But…Oh, Never Mind)
Streams (Standard Library)
Case Study: A Message Queue
Case Study: Improving the Message Queue
Twisted
The Janus Queue
aiohttp
Case Study: Hello World
Case Study: Scraping the News
ØMQ (ZeroMQ)
Case Study: Multiple Sockets
Case Study: Application Performance Monitoring
asyncpg and Sanic
Case Study: Cache Invalidation
Other Libraries and Resources
5. Concluding Thoughts

A. A Short History of Async Support in Python
In the Beginning, There Was asyncore
The Path to Native Coroutines

B. Supplementary Material
Cutlery Example Using Asyncio
Supplementary Material for News Website Scraper
Supplementary Material for the ZeroMQ Case Study
Database Trigger Handling for the asyncpg Case Study
Supplementary Material for the Sanic Example: aelapsed and aprofiler

Index