The Tulip project is the asyncio module for Python 3.3. Since Python 3.4, asyncio is now part of the standard library.

Help:

• asyncio documentation
• asyncio examples
• Mailing list: python-tulip Google Group
• IRC: #asyncio channel on the Freenode network

Pages:

• Contributing: To contribute.
• ThirdParty: A list of 3rd party integrations with asyncio.
• Benchmarks: asyncio benchmarks

The asyncio 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 the concurrent.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 Futures 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.

Hello World using an asyncio coroutine:

import asyncio

@asyncio.coroutine
def hello_world():
    print("Hello World!")

loop = asyncio.get_event_loop()
loop.run_until_complete(hello_world())
loop.close()

For AsyncIO on Python 2, see the trollius project.