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Python has had async for 10 years – why isn't it more popular?

(tonybaloney.github.io)
320 points willm | 2 comments | 02 Sep 25 17:24 UTC | HN request time: 0.456s | source
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atomicnumber3 ◴[02 Sep 25 17:41 UTC] No.45106455[source]▶
The author gets close to what I think the root problem is, but doesn't call it out.

The truth is that in python, async was too little, too late. By the time it was introduced, most people who actually needed to do lots of io concurrently had their own workarounds (forking, etc) and people who didn't actually need it had found out how to get by without it (multiprocessing etc).

Meanwhile, go showed us what good green threads can look like. Then java did it too. Meanwhile, js had better async support the whole time. But all it did was show us that async code just plain sucks compared to green thread code that can just block, instead of having to do the async dances.

So, why engage with it when you already had good solutions?

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1. jongjong ◴[02 Sep 25 21:53 UTC] No.45109610[source]▶
Yes and JS had a smooth on-ramp to async/await thanks to Promises.

Promises/thenables gave people the time to get used to the idea of deferred evaluation via a familiar callback approach... Then when async/await came along, people didn't see it as a radically new feature but more as syntactic sugar to do what they were already doing in a more succinct way without callbacks.

People in the Node.js community were very aware of async concepts since the beginning and put a lot of effort in not blocking the event loop. So Promises and then async/await were seen as solutions to existing pain points which everyone was already familiar with. A lot of people refactored their existing code to async/await.

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2. laurencerowe ◴[02 Sep 25 22:51 UTC] No.45110140[source]▶
JavaScript’s Promises were of course heavily influenced by Twisted’s Deferreds in Python, from the days before async/await.