asyncio
— Asynchronous I/O, event loop, coroutines and tasks¶
New in version 3.4.
Source code: :source:`Lib/asyncio/`
This module provides infrastructure for writing single-threaded concurrent code using coroutines, multiplexing I/O access over sockets and other resources, running network clients and servers, and other related primitives. Here is a more detailed list of the package contents:
- a pluggable event loop with various system-specific implementations;
- transport and protocol abstractions (similar to those in Twisted);
- concrete support for TCP, UDP, SSL, subprocess pipes, delayed calls, and others (some may be system-dependent);
- a
Future
class that mimics the one in theconcurrent.futures
module, but adapted for use with the event loop; - coroutines and tasks based on
yield from
(PEP 380), to help write concurrent code in a sequential fashion; - cancellation support for
Future
s and coroutines; - synchronization primitives for use between coroutines in
a single thread, mimicking those in the
threading
module; - an interface for passing work off to a threadpool, for times when you absolutely, positively have to use a library that makes blocking I/O calls.
Asynchronous programming is more complex than classical “sequential” programming: see the Develop with asyncio page which lists common traps and explains how to avoid them. Enable the debug mode during development to detect common issues.
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