cs.queues 20200521

some Queue subclasses and ducktypes

Queue-like items: iterable queues and channels.

Latest release 20200521: IterableQueue,IterablePriorityQueue: simplify wrappers, bypasses weird bug from overengineering these.

Class Channel

A zero-storage data passage. Unlike a Queue(1), put() blocks waiting for the matching get().

Function IterablePriorityQueue(*args, capacity=0, name=None, **kw)

Factory to create an iterable PriorityQueue.

Function IterableQueue(*args, capacity=0, name=None, **kw)

Factory to create an iterable Queue.

Class NullQueue(cs.resources.MultiOpenMixin)

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.

Class PushQueue(cs.resources.MultiOpenMixin)

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.

Class TimerQueue

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

Release Log

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.