diff --git a/Doc/library/asyncio-eventloop.rst b/Doc/library/asyncio-eventloop.rst index 800fae236f1..072d0013183 100644 --- a/Doc/library/asyncio-eventloop.rst +++ b/Doc/library/asyncio-eventloop.rst @@ -649,24 +649,27 @@ Event loop examples .. _asyncio-hello-world-callback: -Hello World with a callback ---------------------------- +Hello World with call_soon() +---------------------------- -Print ``"Hello World"`` every two seconds using a callback scheduled by the -:meth:`BaseEventLoop.call_soon` method:: +Example using the :meth:`BaseEventLoop.call_soon` method to schedule a +callback. The callback displays ``"Hello World"`` and then stops the event +loop:: import asyncio - def print_and_repeat(loop): + def hello_world(loop): print('Hello World') - loop.call_later(2, print_and_repeat, loop) + loop.stop() loop = asyncio.get_event_loop() - loop.call_soon(print_and_repeat, loop) - try: - loop.run_forever() - finally: - loop.close() + + # Schedule a call to hello_world() + loop.call_soon(hello_world, loop) + + # Blocking call interrupted by loop.stop() + loop.run_forever() + loop.close() .. seealso:: @@ -674,6 +677,42 @@ Print ``"Hello World"`` every two seconds using a callback scheduled by the uses a :ref:`coroutine `. +.. _asyncio-date-callback: + +Display the current date with call_later() +------------------------------------------ + +Example of callback displaying the current date every second. The callback uses +the :meth:`BaseEventLoop.call_later` method to reschedule itself during 5 +seconds, and then stops the event loop:: + + import asyncio + import datetime + + def display_date(end_time, loop): + print(datetime.datetime.now()) + if (loop.time() + 1.0) < end_time: + loop.call_later(1, display_date, end_time, loop) + else: + loop.stop() + + loop = asyncio.get_event_loop() + + # Schedule the first call to display_date() + end_time = loop.time() + 5.0 + loop.call_soon(display_date, end_time, loop) + + # Blocking call interrupted by loop.stop() + loop.run_forever() + loop.close() + +.. seealso:: + + The :ref:`coroutine displaying the current date + ` example uses a :ref:`coroutine + `. + + .. _asyncio-watch-read-event: Watch a file descriptor for read events diff --git a/Doc/library/asyncio-task.rst b/Doc/library/asyncio-task.rst index fa95ca98040..21c4e339f57 100644 --- a/Doc/library/asyncio-task.rst +++ b/Doc/library/asyncio-task.rst @@ -77,30 +77,60 @@ Coroutines (and tasks) can only run when the event loop is running. .. _asyncio-hello-world-coroutine: -Example: "Hello World" coroutine -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +Example: Hello World coroutine +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ -Print ``"Hello World"`` every two seconds using a coroutine:: +Example of coroutine displaying ``"Hello World"``:: import asyncio @asyncio.coroutine - def greet_every_two_seconds(): - while True: - print('Hello World') - yield from asyncio.sleep(2) + def hello_world(): + print("Hello World!") loop = asyncio.get_event_loop() - try: - loop.run_until_complete(greet_every_two_seconds()) - finally: - loop.close() + # Blocking call which returns when the hello_world() coroutine is done + loop.run_until_complete(hello_world()) + loop.close() .. seealso:: - The :ref:`Hello World with a callback ` - example uses a callback scheduled by the :meth:`BaseEventLoop.call_soon` - method. + The :ref:`Hello World with call_soon() ` + example uses the :meth:`BaseEventLoop.call_soon` method to schedule a + callback. + + +.. _asyncio-date-coroutine: + +Example: Coroutine displaying the current date +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Example of coroutine displaying the current date every second during 5 seconds +using the :meth:`sleep` function:: + + import asyncio + import datetime + + @asyncio.coroutine + def display_date(loop): + end_time = loop.time() + 5.0 + while True: + print(datetime.datetime.now()) + if (loop.time() + 1.0) >= end_time: + break + yield from asyncio.sleep(1) + + loop = asyncio.get_event_loop() + # Blocking call which returns when the display_date() coroutine is done + loop.run_until_complete(display_date(loop)) + loop.close() + +.. seealso:: + + The :ref:`display the current date with call_later() + ` example uses a callback with the + :meth:`BaseEventLoop.call_later` method. + Example: Chain coroutines ^^^^^^^^^^^^^^^^^^^^^^^^^