Python 3.6 added async generators. (What's an async
generator? Check out my 5-minute lightning talk demo from PyCon 2016.) Python 3.7 adds some more
tools to make them usable, like contextlib.asynccontextmanager
.
This library gives you all that back to Python 3.5.
For example, this code only works in Python 3.6+:
async def load_json_lines(stream_reader):
async for line in stream_reader:
yield json.loads(line)
But this code does the same thing, and works on Python 3.5+:
from async_generator import async_generator, yield_
@async_generator
async def load_json_lines(stream_reader):
async for line in stream_reader:
await yield_(json.loads(line))
Or in Python 3.7, you can write:
from contextlib import asynccontextmanager
@asynccontextmanager
async def background_server():
async with trio.open_nursery() as nursery:
value = await nursery.start(my_server)
try:
yield value
finally:
# Kill the server when the scope exits
nursery.cancel_scope.cancel()
This is the same, but back to 3.5:
from async_generator import async_generator, yield_, asynccontextmanager
@asynccontextmanager
@async_generator
async def background_server():
async with trio.open_nursery() as nursery:
value = await nursery.start(my_server)
try:
await yield_(value)
finally:
# Kill the server when the scope exits
nursery.cancel_scope.cancel()
(And if you're on 3.6, you can use @asynccontextmanager
with
native generators.)
- Install:
python3 -m pip install -U async_generator
(or on Windows, maybepy -3 -m pip install -U async_generator
- Manual: https://async-generator.readthedocs.io/
- Bug tracker and source code: https://github.com/python-trio/async_generator
- Real-time chat: https://gitter.im/python-trio/general
- License: MIT or Apache 2, your choice
- Contributor guide: https://trio.readthedocs.io/en/latest/contributing.html
- Code of conduct: Contributors are requested to follow our code of conduct in all project spaces.
Trio is a new async concurrency
library for Python that's obsessed with usability and correctness โ we
want to make it easy to get things right. The async_generator
library is maintained by the Trio project as part of that mission, and
because Trio uses async_generator
internally.
You can use async_generator
with any async library. It works great
with asyncio
, or Twisted, or whatever you like. (But we think Trio
is pretty sweet.)