[3.11] gh-108973: Fix asyncio SubprocessProtocol doc (#109431) (#109610)

gh-108973: Fix asyncio SubprocessProtocol doc (#109431)

SubprocessProtocol process_exited() method can be called before
pipe_data_received() and pipe_connection_lost() methods. Document it
and adapt the example in the doc.

Co-authored-by: Davide Rizzo <sorcio@gmail.com>
(cherry picked from commit ced6924630)
This commit is contained in:
Victor Stinner 2023-09-20 16:15:08 +02:00 committed by GitHub
parent 17a335dd02
commit 336dbe56b2
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2 changed files with 23 additions and 6 deletions

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@ -484,19 +484,19 @@ Protocol classes can implement the following **callback methods**:
:widths: 50 50
:class: full-width-table
* - ``callback`` :meth:`pipe_data_received()
<SubprocessProtocol.pipe_data_received>`
* - ``callback`` :meth:`~SubprocessProtocol.pipe_data_received`
- Called when the child process writes data into its
*stdout* or *stderr* pipe.
* - ``callback`` :meth:`pipe_connection_lost()
<SubprocessProtocol.pipe_connection_lost>`
* - ``callback`` :meth:`~SubprocessProtocol.pipe_connection_lost`
- Called when one of the pipes communicating with
the child process is closed.
* - ``callback`` :meth:`process_exited()
<SubprocessProtocol.process_exited>`
- Called when the child process has exited.
- Called when the child process has exited. It can be called before
:meth:`~SubprocessProtocol.pipe_data_received` and
:meth:`~SubprocessProtocol.pipe_connection_lost` methods.
Event Loop Policies

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@ -708,6 +708,9 @@ factories passed to the :meth:`loop.subprocess_exec` and
Called when the child process has exited.
It can be called before :meth:`~SubprocessProtocol.pipe_data_received` and
:meth:`~SubprocessProtocol.pipe_connection_lost` methods.
Examples
========
@ -1003,12 +1006,26 @@ The subprocess is created by the :meth:`loop.subprocess_exec` method::
def __init__(self, exit_future):
self.exit_future = exit_future
self.output = bytearray()
self.pipe_closed = False
self.exited = False
def pipe_connection_lost(self, fd, exc):
self.pipe_closed = True
self.check_for_exit()
def pipe_data_received(self, fd, data):
self.output.extend(data)
def process_exited(self):
self.exit_future.set_result(True)
self.exited = True
# process_exited() method can be called before
# pipe_connection_lost() method: wait until both methods are
# called.
self.check_for_exit()
def check_for_exit(self):
if self.pipe_closed and self.exited:
self.exit_future.set_result(True)
async def get_date():
# Get a reference to the event loop as we plan to use