[Python-Dev] Should asyncio ignore KeyboardInterrupt?

Guido van Rossum guido at python.org
Sat Jul 4 17:46:34 CEST 2015


I think this may be more of a Windows issue than an asyncio issue. I agree
that ideally ^C should take effect immediately (as it does on UNIX).

On Sat, Jul 4, 2015 at 9:54 AM, Terry Reedy <tjreedy at udel.edu> wrote:

> Should the loop.run... methods of asyncio respect KeyboardInterrupt (^C)?
>
> Developer and user convenience and this paragraph in PEP
>
> "However, exceptions deriving only from BaseException are typically not
> caught, and will usually cause the program to terminate with a traceback.
> In some cases they are caught and re-raised. (Examples of this category
> include KeyboardInterrupt and SystemExit ; it is usually unwise to treat
> these the same as most other exceptions.) "
>
> and this examples in the doc (two places)
>
> TCP echo server
>     # Serve requests until CTRL+c is pressed
>     print('Serving on {}'.format(server.sockets[0].getsockname()))
>     try:
>         loop.run_forever()
>     except KeyboardInterrupt:
>         pass
>
> suggest yes.  On the other hand, the section on
> "Set signal handlers for SIGINT and SIGTERM"
> suggests not, unless an explicit handler is registered and then only on
> Unix.
>
> In any case, Adam Bartos, python-list, "An asyncio example", today asks.
> '''
> This is a minimal example:
>
> import asyncio
>
> async def wait():
>     await asyncio.sleep(5)
>
> loop = asyncio.get_event_loop()
> loop.run_until_complete(wait())
>
> Ctrl-C doesn't interrupt the waiting, instead KeyboardInterrupt occurs
> after those five seconds. It's 3.5.0b2 on Windows. Is it a bug?
> '''
>
> Using run_forever instead, I found no way to stop other than killing the
> process (Idle or Command Prompt).
>
> --
> Terry Jan Reedy
>
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-- 
--Guido van Rossum (python.org/~guido)
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