Metadata-Version: 2.1
Name: cs.queues
Version: 20230331
Summary: some Queue subclasses and ducktypes
Home-page: https://bitbucket.org/cameron_simpson/css/commits/all
Author: Cameron Simpson
Author-email: Cameron Simpson <cs@cskk.id.au>
License: GNU General Public License v3 or later (GPLv3+)
Project-URL: URL, https://bitbucket.org/cameron_simpson/css/commits/all
Keywords: python2,python3
Classifier: Programming Language :: Python
Classifier: Programming Language :: Python :: 2
Classifier: Programming Language :: Python :: 3
Classifier: Development Status :: 4 - Beta
Classifier: Intended Audience :: Developers
Classifier: Operating System :: OS Independent
Classifier: Topic :: Software Development :: Libraries :: Python Modules
Classifier: License :: OSI Approved :: GNU General Public License v3 or later (GPLv3+)
Description-Content-Type: text/markdown
Requires-Dist: cs.logutils (>=20230212)
Requires-Dist: cs.obj (>=20220918)
Requires-Dist: cs.pfx (>=20230331)
Requires-Dist: cs.py3 (>=20220523)
Requires-Dist: cs.resources (>=20230331)
Requires-Dist: cs.seq (>=20221118)

Queue-like items: iterable queues, channels, etc.

*Latest release 20230331*:
* QueueIterator.startup_shutdown: try/finally for the terminating _put(self.sentinel).
* QueueIterator.__str__: show the underlying queue.
* QueueIterator: drop call to self.finalise(), no longer available or needed.

## Class `Channel`

A zero-storage data passage.
Unlike a `Queue`, `put(item)` blocks waiting for the matching `get()`.

*Method `Channel.__init__(self)`*:
pylint: disable=consider-using-with

## Function `IterablePriorityQueue(capacity=0, name=None)`

Factory to create an iterable `PriorityQueue`.

## Function `IterableQueue(capacity=0, name=None)`

Factory to create an iterable queue.
Note that the returned queue is already open
and needs a close.

## Class `ListQueue`

A simple iterable queue based on a `list`.

*Method `ListQueue.__init__(self, queued=None)`*:
Initialise the queue.
`queued` is an optional iterable of initial items for the queue.

## `NullQ = <NullQueue:NullQ blocking=False>`

A queue-like object that discards its inputs.
Calls to `.get()` raise `Queue_Empty`.

## Class `NullQueue(cs.resources.MultiOpenMixin, cs.context.ContextManagerMixin)`

A queue-like object that discards its inputs.
Calls to `.get()` raise `Queue_Empty`.

*Method `NullQueue.__init__(self, blocking=False, name=None)`*:
Initialise the `NullQueue`.

Parameters:
* `blocking`: optional; if true, calls to `.get()` block until
  `.shutdown()`; default: `False`.
* `name`: optional name for this `NullQueue`.

## Class `PushQueue(cs.resources.MultiOpenMixin, cs.context.ContextManagerMixin)`

A puttable object which looks like an iterable `Queue`.

In this base class,
calling `.put(item)` calls `functor` supplied at initialisation
to trigger a function on data arrival
whose iterable of results are put onto the output queue.

As an example, the `cs.pipeline.Pipeline` class
uses subclasses of `PushQueue` for each pipeline stage,
overriding the `.put(item)` method
to mediate the call of `functor` through `cs.later.Later`
as resource controlled concurrency.

*Method `PushQueue.__init__(self, name, functor, outQ)`*:
Initialise the PushQueue with the callable `functor`
and the output queue `outQ`.

Parameters:
* `functor` is a one-to-many function which accepts a single
  item of input and returns an iterable of outputs; it may be a
  generator. These outputs are passed to `outQ.put` individually as
  received.
* `outQ` is a `MultiOpenMixin` which accepts via its `.put()` method.

## Class `QueueIterator(cs.resources.MultiOpenMixin, cs.context.ContextManagerMixin)`

A `QueueIterator` is a wrapper for a `Queue` (or ducktype) which
presents an iterator interface to collect items.
It does not offer the `.get` or `.get_nowait` methods.

## Class `TimerQueue`

Class to run a lot of "in the future" jobs without using a bazillion
Timer threads.

# Release Log



*Release 20230331*:
* QueueIterator.startup_shutdown: try/finally for the terminating _put(self.sentinel).
* QueueIterator.__str__: show the underlying queue.
* QueueIterator: drop call to self.finalise(), no longer available or needed.

*Release 20221228*:
Minor doc update.

*Release 20221207*:
PushQueue: modernise the MutiOpenMixin startup_shutdown, do both open and close of self.outQ.

*Release 20220918*:
Expose formerly private _QueueIterator as QueueIterator, use a per-queue sentinel from cs.obj.Sentinel.

*Release 20220805*:
ListQueue: add "append" synonym for "put" in keeping with the list-ish flavour.

*Release 20220605*:
ListQueue: extend/prepend: reject str explicitly - although iterable, it is almost never what is intended.

*Release 20220317*:
Add missed import.

*Release 20220313*:
New ListQueue.prepend(items[,offset=0]) method.

*Release 20211116*:
ListQueue: new insert() method.

*Release 20210924*:
Channel: make a Channel iterable.

*Release 20210913*:
New ListQueue simple iterable queue based on a list with list-like .append and .extend.

*Release 20201025*:
Drop obsolete call to MultiOpenMixin.__init__.

*Release 20200718*:
_QueueIterator: set finalise_later via new MultiOpenMixin property, required by recent MultiOpenMixin change.

*Release 20200521*:
IterableQueue,IterablePriorityQueue: simplify wrappers, bypasses weird bug from overengineering these.

*Release 20191007*:
* PushQueue: improve __str__.
* Clean lint, drop cs.obj dependency.

*Release 20190812*:
_QueueIterator: do MultiOpenMixin.__init__ so that __str__ is functional.

*Release 20181022*:
Bugfix Channel, drasticly simplify PushQueue, other minor changes.

*Release 20160828*:
* Use "install_requires" instead of "requires" in DISTINFO.
* TimerQueue.add: support optional *a and **kw arguments for func.
* Many bugfixes and internal changes.

*Release 20150115*:
More PyPI metadata fixups.

*Release 20150111*:
Initial PyPI release.
