Trio on Pythonista
I am trying to get trio run on Puthonista, as a more sane replacement for asyncio. Installs fine, if you also install the contextvars dependency, but there is a show-stopper problem with SIGINT handling.
So, I am fascinated by the async stuff, and by Trio, as it seems very thoroughly thought out, and much less prone to random exceptions than asyncio.
So here's the traditional experiment, parallel loading of web pages. I have a list of 56 highest-traffic sites. Straight-forward site-after-site fetch takes around a minute and a half on my network.
To use Trio for fetching web pages on Pythonista, you need to pip install:
Also, you need to include the following, to circumvent or silence errors and warnings due to the way Pythonista has set up signal and sys.excepthook handling:
import warnings, signal with warnings.catch_warnings(): warnings.simplefilter("ignore") import trio signal.signal(signal.SIGINT, signal.SIG_DFL)
Reward here is of course that the same list can then be fetched in parallel and in 4-6 seconds, or in 1/20th of the time that the sequential approach takes.
s = asks.Session(connections=100) async def grabber(site): r = await s.get('https://'+site, timeout=5) content = r.text print(site) async def main(): async with trio.open_nursery() as n: for site in sites: n.start_soon(grabber, site)
Ok, so then I thought about Scripter, the generator-based asynchronous 'language' originally designed to run off the Pythonista UI loop, running UI animations.
I changed Scripter to use Trio as the underlying loop, and to be able to call
async deffunctions as part of the scripts. Here is the Scripter version of the above trio code:
@script def retrieve_all(): for site in sites: worker(site) print(site) @script def worker(site): result = get('https://'+site, timeout=5) yield content = result.value.text
I have gotten so used to Scripter that I much prefer the "parallel by default" way it operates. This is of course somewhat in opposition to the "explicit parallelism" philosophy of the asyncio/trio crowd.