| :mod:`asyncio` --- Asynchronous I/O |
| =================================== |
| |
| .. module:: asyncio |
| :synopsis: Asynchronous I/O. |
| |
| -------------- |
| |
| .. sidebar:: Hello World! |
| |
| :: |
| |
| import asyncio |
| |
| async def main(): |
| print('Hello ...') |
| await asyncio.sleep(1) |
| print('... World!') |
| |
| # Python 3.7+ |
| asyncio.run(main()) |
| |
| 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-level |
| **structured** network code. |
| |
| asyncio provides a set of **high-level** APIs to: |
| |
| * :ref:`run Python coroutines <coroutine>` concurrently and |
| have full control over their execution; |
| |
| * perform :ref:`network IO and IPC <asyncio-streams>`; |
| |
| * control :ref:`subprocesses <asyncio-subprocess>`; |
| |
| * distribute tasks via :ref:`queues <asyncio-queues>`; |
| |
| * :ref:`synchronize <asyncio-sync>` concurrent code; |
| |
| Additionally, there are **low-level** APIs for |
| *library and framework developers* to: |
| |
| * create and manage :ref:`event loops <asyncio-event-loop>`, which |
| provide asynchronous APIs for :meth:`networking <loop.create_server>`, |
| running :meth:`subprocesses <loop.subprocess_exec>`, |
| handling :meth:`OS signals <loop.add_signal_handler>`, etc; |
| |
| * implement efficient protocols using |
| :ref:`transports <asyncio-transports-protocols>`; |
| |
| * :ref:`bridge <asyncio-futures>` callback-based libraries and code |
| with async/await syntax. |
| |
| |
| .. We use the "rubric" directive here to avoid creating |
| the "Reference" subsection in the TOC. |
| |
| .. rubric:: Reference |
| |
| .. toctree:: |
| :caption: High-level APIs |
| :maxdepth: 1 |
| |
| asyncio-task.rst |
| asyncio-stream.rst |
| asyncio-sync.rst |
| asyncio-subprocess.rst |
| asyncio-queue.rst |
| asyncio-exceptions.rst |
| |
| .. toctree:: |
| :caption: Low-level APIs |
| :maxdepth: 1 |
| |
| asyncio-eventloop.rst |
| asyncio-future.rst |
| asyncio-protocol.rst |
| asyncio-policy.rst |
| asyncio-platforms.rst |
| |
| .. toctree:: |
| :caption: Guides and Tutorials |
| :maxdepth: 1 |
| |
| asyncio-api-index.rst |
| asyncio-llapi-index.rst |
| asyncio-dev.rst |