Can't use asyncio.sleep in gather?

[skyguy]

I tried to add a sleep() to a gather() but MicroPython v1.21 gives me an error "coroutine expected"? Am I doing it wrong?

Simplified example:

import asyncio

async def main():
    await asyncio.gather(asyncio.sleep(5))
    print("done")

asyncio.run(main())

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "gather_sleep_tst.py", line 7, in <module>
  File "asyncio/core.py", line 1, in run
  File "asyncio/core.py", line 1, in run_until_complete
  File "asyncio/core.py", line 1, in run_until_complete
  File "gather_sleep_tst.py", line 4, in main
  File "asyncio/funcs.py", line 1, in gather
  File "asyncio/funcs.py", line 1, in <listcomp>
  File "asyncio/core.py", line 1, in _promote_to_task
  File "asyncio/core.py", line 1, in create_task
TypeError: coroutine expected

Thanks in advance
-Kevin

[mendenm]

shouldn't that be a 1-item tuple (or a list):

import asyncio

async def main():
    await asyncio.gather((asyncio.sleep(5),))
    print("done")

asyncio.run(main())

since gather wants an iterable?

[peterhinch]

To avoid confusion gather does not want an iterable. It takes an arbitrary number of positional args each of which is an awaitable. If aws is a sequence of awaitable objects the call signature is

awaitable asyncio.gather(*aws, return_exceptions=False)  # aws is unpacked

[skyguy]

Thanks for the clarification, and a special thanks for all the tutorials and clarifications you've published. Most of my questions while learning MicroPython were answered by something you wrote!

[jimmo]

@skyguy For efficiency, asyncio.sleep is a bit "magic" and isn't implemented as a true coroutine. You'll need to wrap it in a task to make this work.

(It's worth it though, this optimisation means you can do await asyncio.sleep without causing an allocation)

[skyguy]

OK, thanks. I'll try it that way.

[mendenm]

Oops, my apology. I should have re-checked. Marcus

…

On Nov 22, 2023, at 4:51 AM, Peter Hinch ***@***.***> wrote: To avoid confusion gather does not want an iterable. It takes an arbitrary number of positional args each of which is an awaitable. If aws is a sequence of awaitable objects the call signature is awaitable asyncio.gather(*aws, return_exceptions=False) # aws is unpacked — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you commented.Message ID: ***@***.***>