diff options
| -rw-r--r-- | Doc/library/asyncio-eventloop.rst | 11 | ||||
| -rw-r--r-- | Doc/library/asyncio-runner.rst | 6 | ||||
| -rw-r--r-- | Lib/asyncio/base_events.py | 17 | ||||
| -rw-r--r-- | Lib/asyncio/constants.py | 3 | ||||
| -rw-r--r-- | Lib/asyncio/runners.py | 13 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2019-09-25-00-37-51.bpo-38267.X9Jb5V.rst | 3 |
6 files changed, 44 insertions, 9 deletions
diff --git a/Doc/library/asyncio-eventloop.rst b/Doc/library/asyncio-eventloop.rst index b61ffd5..0a960ab 100644 --- a/Doc/library/asyncio-eventloop.rst +++ b/Doc/library/asyncio-eventloop.rst @@ -180,18 +180,27 @@ Running and stopping the loop .. versionadded:: 3.6 -.. coroutinemethod:: loop.shutdown_default_executor() +.. coroutinemethod:: loop.shutdown_default_executor(timeout=None) Schedule the closure of the default executor and wait for it to join all of the threads in the :class:`ThreadPoolExecutor`. After calling this method, a :exc:`RuntimeError` will be raised if :meth:`loop.run_in_executor` is called while using the default executor. + The *timeout* parameter specifies the amount of time the executor will + be given to finish joining. The default value is ``None``, which means the + executor will be given an unlimited amount of time. + + If the timeout duration is reached, a warning is emitted and executor is + terminated without waiting for its threads to finish joining. + Note that there is no need to call this function when :func:`asyncio.run` is used. .. versionadded:: 3.9 + .. versionchanged:: 3.12 + Added the *timeout* parameter. Scheduling callbacks ^^^^^^^^^^^^^^^^^^^^ diff --git a/Doc/library/asyncio-runner.rst b/Doc/library/asyncio-runner.rst index 4abe7b6..c43d664 100644 --- a/Doc/library/asyncio-runner.rst +++ b/Doc/library/asyncio-runner.rst @@ -28,7 +28,7 @@ Running an asyncio Program This function runs the passed coroutine, taking care of managing the asyncio event loop, *finalizing asynchronous - generators*, and closing the threadpool. + generators*, and closing the executor. This function cannot be called when another asyncio event loop is running in the same thread. @@ -41,6 +41,10 @@ Running an asyncio Program the end. It should be used as a main entry point for asyncio programs, and should ideally only be called once. + The executor is given a timeout duration of 5 minutes to shutdown. + If the executor hasn't finished within that duration, a warning is + emitted and the executor is closed. + Example:: async def main(): diff --git a/Lib/asyncio/base_events.py b/Lib/asyncio/base_events.py index a675fff..9c9d98d 100644 --- a/Lib/asyncio/base_events.py +++ b/Lib/asyncio/base_events.py @@ -561,8 +561,13 @@ class BaseEventLoop(events.AbstractEventLoop): 'asyncgen': agen }) - async def shutdown_default_executor(self): - """Schedule the shutdown of the default executor.""" + async def shutdown_default_executor(self, timeout=None): + """Schedule the shutdown of the default executor. + + The timeout parameter specifies the amount of time the executor will + be given to finish joining. The default value is None, which means + that the executor will be given an unlimited amount of time. + """ self._executor_shutdown_called = True if self._default_executor is None: return @@ -572,7 +577,13 @@ class BaseEventLoop(events.AbstractEventLoop): try: await future finally: - thread.join() + thread.join(timeout) + + if thread.is_alive(): + warnings.warn("The executor did not finishing joining " + f"its threads within {timeout} seconds.", + RuntimeWarning, stacklevel=2) + self._default_executor.shutdown(wait=False) def _do_shutdown(self, future): try: diff --git a/Lib/asyncio/constants.py b/Lib/asyncio/constants.py index f171ead..f0ce043 100644 --- a/Lib/asyncio/constants.py +++ b/Lib/asyncio/constants.py @@ -26,6 +26,9 @@ SENDFILE_FALLBACK_READBUFFER_SIZE = 1024 * 256 FLOW_CONTROL_HIGH_WATER_SSL_READ = 256 # KiB FLOW_CONTROL_HIGH_WATER_SSL_WRITE = 512 # KiB +# Default timeout for joining the threads in the threadpool +THREAD_JOIN_TIMEOUT = 300 + # The enum should be here to break circular dependencies between # base_events and sslproto class _SendfileMode(enum.Enum): diff --git a/Lib/asyncio/runners.py b/Lib/asyncio/runners.py index 840b133..b1c4dbd 100644 --- a/Lib/asyncio/runners.py +++ b/Lib/asyncio/runners.py @@ -9,7 +9,7 @@ from . import coroutines from . import events from . import exceptions from . import tasks - +from . import constants class _State(enum.Enum): CREATED = "created" @@ -69,7 +69,8 @@ class Runner: loop = self._loop _cancel_all_tasks(loop) loop.run_until_complete(loop.shutdown_asyncgens()) - loop.run_until_complete(loop.shutdown_default_executor()) + loop.run_until_complete( + loop.shutdown_default_executor(constants.THREAD_JOIN_TIMEOUT)) finally: if self._set_event_loop: events.set_event_loop(None) @@ -160,8 +161,8 @@ def run(main, *, debug=None): """Execute the coroutine and return the result. This function runs the passed coroutine, taking care of - managing the asyncio event loop and finalizing asynchronous - generators. + managing the asyncio event loop, finalizing asynchronous + generators and closing the default executor. This function cannot be called when another asyncio event loop is running in the same thread. @@ -172,6 +173,10 @@ def run(main, *, debug=None): It should be used as a main entry point for asyncio programs, and should ideally only be called once. + The executor is given a timeout duration of 5 minutes to shutdown. + If the executor hasn't finished within that duration, a warning is + emitted and the executor is closed. + Example: async def main(): diff --git a/Misc/NEWS.d/next/Library/2019-09-25-00-37-51.bpo-38267.X9Jb5V.rst b/Misc/NEWS.d/next/Library/2019-09-25-00-37-51.bpo-38267.X9Jb5V.rst new file mode 100644 index 0000000..b842fdc --- /dev/null +++ b/Misc/NEWS.d/next/Library/2019-09-25-00-37-51.bpo-38267.X9Jb5V.rst @@ -0,0 +1,3 @@ +Add *timeout* parameter to :meth:`asyncio.loop.shutdown_default_executor`. +The default value is ``None``, which means the executor will be given an unlimited amount of time. +When called from :class:`asyncio.Runner` or :func:`asyncio.run`, the default timeout is 5 minutes. |