asyncio-thread-runner 1.0

Run async code from sync code.

you can have a little async (as a treat)

asyncio-thread-runner allows you to run async code from sync code.

This is useful when you're doing some sync stuff, but:

• you also need to do some async stuff, without making everything async
• maybe the sync stuff is an existing application
• maybe you still want to use your favorite sync library
• or maybe you need just a little async, without having to pay the full price

Features:

• unlike asyncio.run(), it provides a long-lived event loop
• unlike asyncio.Runner, it runs in a dedicated thread, and you can use it from multiple threads
• it allows you to use async context managers and iterables from sync code
• check out this article for why these are useful

Usage:

$ pip install asyncio-thread-runner

>>> async def double(i):
...     return i * 2
...
>>> from asyncio_thread_runner import ThreadRunner
>>> runner = ThreadRunner()
>>> runner.run(double(2))
4

Annotated example:

import aiohttp
from asyncio_thread_runner import ThreadRunner

# you can use ThreadRunner as a context manager,
# or call runner.close() when you're done with it
with ThreadRunner() as runner:

    # aiohttp.ClientSession() should be used as an async context manager,
    # enter_context() will exit the context on runner shutdown;
    # because instantiating ClientSession requires a running event loop,
    # we pass it as a factory instead of calling it in the main thread
    session = runner.enter_context(aiohttp.ClientSession)

    # session.get() returns an async context manager...
    request = session.get('https://death.andgravity.com/asyncio-bridge')
    # which we turn into a normal one with wrap_context()
    with runner.wrap_context(request) as response:

        # response.content is an async iterator;
        # we turn it into a normal iterator with wrap_iter()
        lines = list(runner.wrap_iter(response.content))

    # "got 935 lines"
    print('got', len(lines), 'lines')