Asynchronous programming

[Steven D'Aprano]

On Fri, 12 Aug 2016 03:47 pm, Paul Rudin wrote:

> Steven D'Aprano <steve+python at pearwood.info> writes:
> 
>> Thanks to everyone who has answered, I think I'm slowly starting to get
>> it now. Let's see if we can come up with a toy example that doesn't
>> involve low-level socket programming :-)
>>
>> Let me simulate a slow function call:

[...]
> They're not separate processes or threads, just think tasks that suspend
> and restart cooperatively. You need some kind of event loop to
> orchestrate running the tasks. Asyncio provides one.
> 
> You can do your example like this:
> 
> import asyncio, random
> 
> async def work(id):
>     print("starting with id", id)
>     workload = random.randint(5, 15)
>     for i in range(workload):
>         await asyncio.sleep(0.2)  # pretend to do some real work
>         print("processing id", id)  # let the user see some progress
>     print("done with id", id)
>     return 10 + id
> 
> loop = asyncio.get_event_loop()
> 
> pending = [1, 2, 3, 4]
> 
> jobs = [asyncio.ensure_future(work(n)) for n in pending]
>      
> loop.run_until_complete(asyncio.gather(*jobs))
> 
> loop.close()


That is *awesome*. Thank you for the example!





-- 
Steve
“Cheer up,” they said, “things could be worse.” So I cheered up, and sure
enough, things got worse.