Mohamed Mustapha Tahrioui - asyncio Recipes: A Problem-Solution Approach

The Python programming language adopted a preemptive concurrency framework in the early 90s via the threading module, which strived to mimic the Java concurrency library, as per the respective commit message.

A simple but powerful mechanism governs concurrent execution of bytecode in most Python implementations. This mechanism is called the GIL (global interpreter lock). The interpreter consumes one bytecode instruction at a time.

This effectively means that only one thread can run at the same time (in one interpreter process). Despite this fact, the underlying native thread implementation might be able to run more than one thread at a time.

The threads are appointed fair amounts of CPU time. Without employing sophisticated introspection techniques, this boils down to simple/naive time-based scheduling algorithms.

Taking this approach in the past would often yield inferior solutions to an equivalent single threaded program, for Python implementation with a GIL like CPython.

Since removing the GIL is not an option, failed because they degraded the single threading performance significantly, the concurrency situation meant having only the threading module.

The cooperative concurrency framework asyncio was written to address the need for fast single-threaded programs that don't waste CPU time on I/O bound tasks.

Its primitives like coroutines and event loops allow developers to execute code only when its not waiting for I/O and to yield control back for other tasks.

Since its advent, asyncio has added countless APIs and keywords to the Python language ( async / await ). Its steep learning curve scares some developers from trying it. However, its a powerful technology thats even been used by big players like Instagram .

The motivation of this book is to help more developers adopt asyncio and experience the joy of using asyncio for fun and profit. With that said, enjoy this book while learning more about asyncio!

I would like to express my deep gratitude to

Mrs. Aditee Mirashi

Mr. Todd Green

Mr. Celestin Suresh John

Mr. James Markham

Mr. Matthew Moodle

Mr. Said El Mallouki

for their invaluable efforts during the execution of my book.

Furthermore, my special thanks are extended to my company axxessio and in special to

Mr. Goodarz Mahboobi

Mr. Keyvan Mahbobi