asyncio — Asynchronous I/O (original) (raw)

asyncio is a library to write concurrent code using the async/await syntax.

asyncio is used as a foundation for multiple Python asynchronous frameworks that provide high-performance network and web-servers, database connection libraries, distributed task queues, etc.

asyncio is often a perfect fit for IO-bound and high-levelstructured network code.

asyncio provides a set of high-level APIs to:

• run Python coroutines concurrently and have full control over their execution;
• perform network IO and IPC;
• control subprocesses;
• distribute tasks via queues;
• synchronize concurrent code;

Additionally, there are low-level APIs for_library and framework developers_ to:

• create and manage event loops, which provide asynchronous APIs for networking, running subprocesses, handling OS signals, etc;
• implement efficient protocols usingtransports;
• bridge callback-based libraries and code with async/await syntax.

asyncio REPL

You can experiment with an asyncio concurrent context in the REPL:

$ python -m asyncio asyncio REPL ... Use "await" directly instead of "asyncio.run()". Type "help", "copyright", "credits" or "license" for more information.

import asyncio await asyncio.sleep(10, result='hello') 'hello'

Raises an auditing event cpython.run_stdin with no arguments.

Changed in version 3.12.5: (also 3.11.10, 3.10.15, 3.9.20, and 3.8.20) Emits audit events.

Changed in version 3.13: Uses PyREPL if possible, in which case PYTHONSTARTUP is also executed. Emits audit events.

Reference

Note

The source code for asyncio can be found in Lib/asyncio/.