Skip to content

Fix docs for Queue.shutdown #137028

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 14 commits into from
Jul 24, 2025
Merged
Changes from 3 commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
46 changes: 32 additions & 14 deletions Doc/library/queue.rst
Original file line number Diff line number Diff line change
Expand Up @@ -187,9 +187,6 @@ fully processed by daemon consumer threads.
processed (meaning that a :meth:`task_done` call was received for every item
that had been :meth:`put` into the queue).

``shutdown(immediate=True)`` calls :meth:`task_done` for each remaining item
in the queue.

Raises a :exc:`ValueError` if called more times than there were items placed in
the queue.

Expand Down Expand Up @@ -233,22 +230,43 @@ Example of how to wait for enqueued tasks to be completed::
Terminating queues
^^^^^^^^^^^^^^^^^^

:class:`Queue` objects can be made to prevent further interaction by shutting
them down.
When no longer needed, :class:`Queue` objects can be wound down
or terminated immediately.

.. method:: Queue.shutdown(immediate=False)

Shut down the queue, making :meth:`~Queue.get` and :meth:`~Queue.put` raise
:exc:`ShutDown`.
Put a :class:`Queue` instance into a shutdown mode.

The queue can no longer grow.
Future calls to :meth:`~Queue.put` raise :exc:`ShutDown`.
Currently blocked callers of :meth:`~Queue.put` will be unblocked
and will raise :exc:`ShutDown` in the formerly blocked thread.

If *immediate* is false (the default), the queue can be wound
down normally with calls :meth:`~Queue.get` to extract tasks
that have already been loaded.

If the shutdown occurs during the brief window where the queue still
has data and callers to :meth:`~Queue.get` are blocked, those callers
will be unblocked.

And if :meth:`~Queue.task_done` is called for each remaining task, a
pending :meth:`~Queue.join` will be unblocked normally.

Once the queue is empty, future calls to :meth:`~Queue.get` will
raise :exc:`ShutDown`.

By default, :meth:`~Queue.get` on a shut down queue will only raise once the
queue is empty. Set *immediate* to true to make :meth:`~Queue.get` raise
immediately instead.
If *immediate* is true, the queue is terminated immediately.
The queue is drained to be completely empty. The count of
unfinished tasks is reduced by number drained but without calling
:meth:`~Queue.task_done`. All callers of :meth:`~Queue.join`
are unblocked even if the unfinished tasks is more than zero.
In addition, blocked callers of
:meth:`~Queue.get` are unblocked and will raise :exc:`ShutDown`.

All blocked callers of :meth:`~Queue.put` and :meth:`~Queue.get` will be
unblocked. If *immediate* is true, a task will be marked as done for each
remaining item in the queue, which may unblock callers of
:meth:`~Queue.join`.
Use caution when using :meth:`~Queue.join` with *immediate* set
to true. This unblocks the join even when no work has been done
on the tasks, violating the usual invariant for joining a queue.

.. versionadded:: 3.13

Expand Down
Loading
pFad - Phonifier reborn

Pfad - The Proxy pFad of © 2024 Garber Painting. All rights reserved.

Note: This service is not intended for secure transactions such as banking, social media, email, or purchasing. Use at your own risk. We assume no liability whatsoever for broken pages.


Alternative Proxies:

Alternative Proxy

pFad Proxy

pFad v3 Proxy

pFad v4 Proxy