some Queue subclasses and ducktypes
Project description
Queue-like items: iterable queues and channels.
Latest release 20220313: New ListQueue.prepend(items[,offset=0]) method.
Class Channel
A zero-storage data passage. Unlike a Queue(1), put() blocks waiting for the matching get().
Method Channel.__init__(self)
:
pylint: disable=consider-using-with
Method Channel.__call__(self, *a)
:
Call the Channel.
With no arguments, do a .get().
With an argument, do a .put().
Method Channel.__iter__(self)
:
A Channel
is iterable.
Method Channel.__next__(self)
:
next(Channel)
calls Channel.get()
.
Method Channel.__str__(self)
:
pylint: disable=consider-using-with
Method Channel.close(self)
:
Close the Channel, preventing further puts.
Method Channel.get(self, *a, **kw)
:
Wrapper function to check that this instance is not closed.
Method Channel.put(self, *a, **kw)
:
Wrapper function to check that this instance is not closed.
Function IterablePriorityQueue(capacity=0, name=None)
Factory to create an iterable PriorityQueue.
Function IterableQueue(capacity=0, name=None)
Factory to create an iterable Queue.
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.
Method ListQueue.__bool__(self)
:
A ListQueue
looks a bit like a container,
and is false when empty.
Method ListQueue.__iter__(self)
:
A ListQueue
is iterable.
Method ListQueue.__next__(self)
:
Iteration gets from the queue.
Method ListQueue.extend(self, items)
:
Convenient/performant queue-lots-of-items.
Method ListQueue.get(self)
:
Get pops from the start of the list.
Method ListQueue.insert(self, index, item)
:
Insert item
at index
in the queue.
Method ListQueue.prepend(self, items, offset=0)
:
Insert items
at offset
(default 0
, the front of the queue).
Method ListQueue.put(self, item)
:
Put appends to 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
: if true, calls to .get() block until .shutdown(). Default: False.name
: a name for this NullQueue.
Method NullQueue.get(self)
:
Get the next value. Always raises Queue_Empty.
If .blocking, delay until .shutdown().
Method NullQueue.put(self, item)
:
Put a value onto the Queue; it is discarded.
Method NullQueue.shutdown(self)
:
Shut down the queue.
Method NullQueue.startup(self)
:
Start the queue.
Class PushQueue(cs.resources.MultiOpenMixin, cs.context.ContextManagerMixin)
A puttable object which looks like an iterable Queue.
Calling .put(item) calls func_push
supplied at initialisation
to trigger a function on data arrival, whose processing is mediated
queued via a Later for delivery to the output queue.
Method PushQueue.__init__(self, name, functor, outQ)
:
Initialise the PushQueue with the Later L
, 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.
Method PushQueue.put(self, *a, **kw)
:
Wrapper function to check that this instance is not closed.
Method PushQueue.shutdown(self)
:
shutdown() is called by MultiOpenMixin._close() to close
the outQ for real.
Method PushQueue.startup(self)
:
Start up.
Class TimerQueue
Class to run a lot of "in the future" jobs without using a bazillion Timer threads.
Method TimerQueue.add(self, when, func)
:
Queue a new job to be called at 'when'.
'func' is the job function, typically made with functools.partial.
Method TimerQueue.close(self, cancel=False)
:
Close the TimerQueue. This forbids further job submissions.
If cancel
is supplied and true, cancel all pending jobs.
Note: it is still necessary to call TimerQueue.join() to
wait for all pending jobs.
Method TimerQueue.join(self)
:
Wait for the main loop thread to finish.
Release Log
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.
Project details
Release history Release notifications | RSS feed
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.