Package: queuelib
Queuelib is a Python library that implements object collections which are stored
in memory or persisted to disk, provide a simple API, and run fast.Queuelib provides collections forqueues(FIFO),stacks(LIFO), queues
sorted by priority and queues that are emptied in around-robinfashion.NoteQueuelib collections are not thread-safe.Queuelib supports Python 3.5+ and has no dependencies.InstallationYou can install Queuelib either via the Python Package Index (PyPI) or from
source.To install using pip:$ pip install queuelibTo install using easy_install:$ easy_install queuelibIf you have downloaded a source tarball you can install it by running the
following (as root):# python setup.py installFIFO/LIFO disk queuesQueuelib provides FIFO and LIFO queue implementations.Here is an example usage of the FIFO queue:>>> from queuelib import FifoDiskQueue
>>> q = FifoDiskQueue("queuefile")
>>> q.push(b'a')
>>> q.push(b'b')
>>> q.push(b'c')
>>> q.pop()
b'a'
>>> q.close()
>>> q = FifoDiskQueue("queuefile")
>>> q.pop()
b'b'
>>> q.pop()
b'c'
>>> q.pop()
>>>The LIFO queue is identical (API-wise), but importingLifoDiskQueueinstead.PriorityQueueA discrete-priority queue implemented by combining multiple FIFO/LIFO queues
(one per priority).First, select the type of queue to be used per priority (FIFO or LIFO):>>> from queuelib import FifoDiskQueue
>>> qfactory = lambda priority: FifoDiskQueue('queue-dir-%s' % priority)Then instantiate the Priority Queue with it:>>> from queuelib import PriorityQueue
>>> pq = PriorityQueue(qfactory)And use it:>>> pq.push(b'a', 3)
>>> pq.push(b'b', 1)
>>> pq.push(b'c', 2)
>>> pq.push(b'd', 2)
>>> pq.pop()
b'b'
>>> pq.pop()
b'c'
>>> pq.pop()
b'd'
>>> pq.pop()
b'a'RoundRobinQueueHas nearly the same interface and implementation as a Priority Queue except
that each element must be pushed with a (mandatory) key.  Popping from the
queue cycles through the keys “round robin”.Instantiate the Round Robin Queue similarly to the Priority Queue:>>> from queuelib import RoundRobinQueue
>>> rr = RoundRobinQueue(qfactory)And use it:>>> rr.push(b'a', '1')
>>> rr.push(b'b', '1')
>>> rr.push(b'c', '2')
>>> rr.push(b'd', '2')
>>> rr.pop()
b'a'
>>> rr.pop()
b'c'
>>> rr.pop()
b'b'
>>> rr.pop()
b'd'Mailing listUse thescrapy-usersmailing list for questions about Queuelib.Bug trackerIf you have any suggestions, bug reports or annoyances please report them to
our issue tracker at:http://github.com/scrapy/queuelib/issues/ContributingDevelopment of Queuelib happens at GitHub:http://github.com/scrapy/queuelibYou are highly encouraged to participate in the development. If you don’t like
GitHub (for some reason) you’re welcome to send regular patches.All changes require tests to be merged.TestsTests are located inqueuelib/testsdirectory. They can be run usingnosetestswith the following command:nosetestsThe output should be something like the following:$ nosetests
.............................................................................
----------------------------------------------------------------------
Ran 77 tests in 0.145s

OKLicenseThis software is licensed under the BSD License. See the LICENSE file in the
top distribution directory for the full license text.VersioningThis software followsSemantic Versioning