Metadata-Version: 1.1
Name: diskcache
Version: 4.1.0
Summary: Disk Cache -- Disk and file backed persistent cache.
Home-page: http://www.grantjenks.com/docs/diskcache/
Author: Grant Jenks
Author-email: contact@grantjenks.com
License: Apache 2.0
Description: DiskCache: Disk Backed Cache
        ============================
        
        `DiskCache`_ is an Apache2 licensed disk and file backed cache library, written
        in pure-Python, and compatible with Django.
        
        The cloud-based computing of 2019 puts a premium on memory. Gigabytes of empty
        space is left on disks as processes vie for memory. Among these processes is
        Memcached (and sometimes Redis) which is used as a cache. Wouldn't it be nice
        to leverage empty disk space for caching?
        
        Django is Python's most popular web framework and ships with several caching
        backends. Unfortunately the file-based cache in Django is essentially
        broken. The culling method is random and large caches repeatedly scan a cache
        directory which slows linearly with growth. Can you really allow it to take
        sixty milliseconds to store a key in a cache with a thousand items?
        
        In Python, we can do better. And we can do it in pure-Python!
        
        ::
        
           In [1]: import pylibmc
           In [2]: client = pylibmc.Client(['127.0.0.1'], binary=True)
           In [3]: client[b'key'] = b'value'
           In [4]: %timeit client[b'key']
        
           10000 loops, best of 3: 25.4 µs per loop
        
           In [5]: import diskcache as dc
           In [6]: cache = dc.Cache('tmp')
           In [7]: cache[b'key'] = b'value'
           In [8]: %timeit cache[b'key']
        
           100000 loops, best of 3: 11.8 µs per loop
        
        **Note:** Micro-benchmarks have their place but are not a substitute for real
        measurements. DiskCache offers cache benchmarks to defend its performance
        claims. Micro-optimizations are avoided but your mileage may vary.
        
        DiskCache efficiently makes gigabytes of storage space available for
        caching. By leveraging rock-solid database libraries and memory-mapped files,
        cache performance can match and exceed industry-standard solutions. There's no
        need for a C compiler or running another process. Performance is a feature and
        testing has 100% coverage with unit tests and hours of stress.
        
        Testimonials
        ------------
        
        `Daren Hasenkamp`_, Founder --
        
            "It's a useful, simple API, just like I love about Redis. It has reduced
            the amount of queries hitting my Elasticsearch cluster by over 25% for a
            website that gets over a million users/day (100+ hits/second)."
        
        `Mathias Petermann`_, Senior Linux System Engineer --
        
            "I implemented it into a wrapper for our Ansible lookup modules and we were
            able to speed up some Ansible runs by almost 3 times. DiskCache is saving
            us a ton of time."
        
        Does your company or website use `DiskCache`_? Send us a `message
        <contact@grantjenks.com>`_ and let us know.
        
        .. _`Daren Hasenkamp`: https://www.linkedin.com/in/daren-hasenkamp-93006438/
        .. _`Mathias Petermann`: https://www.linkedin.com/in/mathias-petermann-a8aa273b/
        
        Features
        --------
        
        - Pure-Python
        - Fully Documented
        - Benchmark comparisons (alternatives, Django cache backends)
        - 100% test coverage
        - Hours of stress testing
        - Performance matters
        - Django compatible API
        - Thread-safe and process-safe
        - Supports multiple eviction policies (LRU and LFU included)
        - Keys support "tag" metadata and eviction
        - Developed on Python 3.7
        - Tested on CPython 2.7, 3.4, 3.5, 3.6, 3.7 and PyPy
        - Tested on Linux, Mac OS X, and Windows
        - Tested using Travis CI and AppVeyor CI
        
        .. image:: https://api.travis-ci.org/grantjenks/python-diskcache.svg?branch=master
            :target: http://www.grantjenks.com/docs/diskcache/
        
        .. image:: https://ci.appveyor.com/api/projects/status/github/grantjenks/python-diskcache?branch=master&svg=true
            :target: http://www.grantjenks.com/docs/diskcache/
        
        Quickstart
        ----------
        
        Installing `DiskCache`_ is simple with `pip <http://www.pip-installer.org/>`_::
        
          $ pip install diskcache
        
        You can access documentation in the interpreter with Python's built-in help
        function::
        
          >>> import diskcache
          >>> help(diskcache)
        
        The core of `DiskCache`_ is three data types intended for caching. `Cache`_
        objects manage a SQLite database and filesystem directory to store key and
        value pairs. `FanoutCache`_ provides a sharding layer to utilize multiple
        caches and `DjangoCache`_ integrates that with `Django`_::
        
          >>> from diskcache import Cache, FanoutCache, DjangoCache
          >>> help(Cache)
          >>> help(FanoutCache)
          >>> help(DjangoCache)
        
        Built atop the caching data types, are `Deque`_ and `Index`_ which work as a
        cross-process, persistent replacements for Python's ``collections.deque`` and
        ``dict``. These implement the sequence and mapping container base classes::
        
          >>> from diskcache import Deque, Index
          >>> help(Deque)
          >>> help(Index)
        
        Finally, a number of `recipes`_ for cross-process synchronization are provided
        using an underlying cache. Features like memoization with cache stampede
        prevention, cross-process locking, and cross-process throttling are available::
        
          >>> from diskcache import memoize_stampede, Lock, throttle
          >>> help(memoize_stampede)
          >>> help(Lock)
          >>> help(throttle)
        
        Python's docstrings are a quick way to get started but not intended as a
        replacement for the `DiskCache Tutorial`_ and `DiskCache API Reference`_.
        
        .. _`Cache`: http://www.grantjenks.com/docs/diskcache/tutorial.html#cache
        .. _`FanoutCache`: http://www.grantjenks.com/docs/diskcache/tutorial.html#fanoutcache
        .. _`DjangoCache`: http://www.grantjenks.com/docs/diskcache/tutorial.html#djangocache
        .. _`Django`: https://www.djangoproject.com/
        .. _`Deque`: http://www.grantjenks.com/docs/diskcache/tutorial.html#deque
        .. _`Index`: http://www.grantjenks.com/docs/diskcache/tutorial.html#index
        .. _`recipes`: http://www.grantjenks.com/docs/diskcache/tutorial.html#recipes
        
        User Guide
        ----------
        
        For those wanting more details, this part of the documentation describes
        tutorial, benchmarks, API, and development.
        
        * `DiskCache Tutorial`_
        * `DiskCache Cache Benchmarks`_
        * `DiskCache DjangoCache Benchmarks`_
        * `Case Study: Web Crawler`_
        * `Case Study: Landing Page Caching`_
        * `Talk: All Things Cached - SF Python 2017 Meetup`_
        * `DiskCache API Reference`_
        * `DiskCache Development`_
        
        .. _`DiskCache Tutorial`: http://www.grantjenks.com/docs/diskcache/tutorial.html
        .. _`DiskCache Cache Benchmarks`: http://www.grantjenks.com/docs/diskcache/cache-benchmarks.html
        .. _`DiskCache DjangoCache Benchmarks`: http://www.grantjenks.com/docs/diskcache/djangocache-benchmarks.html
        .. _`Talk: All Things Cached - SF Python 2017 Meetup`: http://www.grantjenks.com/docs/diskcache/sf-python-2017-meetup-talk.html
        .. _`Case Study: Web Crawler`: http://www.grantjenks.com/docs/diskcache/case-study-web-crawler.html
        .. _`Case Study: Landing Page Caching`: http://www.grantjenks.com/docs/diskcache/case-study-landing-page-caching.html
        .. _`DiskCache API Reference`: http://www.grantjenks.com/docs/diskcache/api.html
        .. _`DiskCache Development`: http://www.grantjenks.com/docs/diskcache/development.html
        
        Comparisons
        -----------
        
        Comparisons to popular projects related to `DiskCache`_.
        
        Key-Value Stores
        ................
        
        `DiskCache`_ is mostly a simple key-value store. Feature comparisons with four
        other projects are shown in the tables below.
        
        * `dbm`_ is part of Python's standard library and implements a generic
          interface to variants of the DBM database — dbm.gnu or dbm.ndbm. If none of
          these modules is installed, the slow-but-simple dbm.dumb is used.
        * `shelve`_ is part of Python's standard library and implements a “shelf” as a
          persistent, dictionary-like object. The difference with “dbm” databases is
          that the values can be anything that the pickle module can handle.
        * `sqlitedict`_ is a lightweight wrapper around Python's sqlite3 database with
          a simple, Pythonic dict-like interface and support for multi-thread
          access. Keys are arbitrary strings, values arbitrary pickle-able objects.
        * `pickleDB`_ is a lightweight and simple key-value store. It is built upon
          Python's simplejson module and was inspired by Redis. It is licensed with the
          BSD three-caluse license.
        
        .. _`dbm`: https://docs.python.org/3/library/dbm.html
        .. _`shelve`: https://docs.python.org/3/library/shelve.html
        .. _`sqlitedict`: https://github.com/RaRe-Technologies/sqlitedict
        .. _`pickleDB`: https://pythonhosted.org/pickleDB/
        
        **Features**
        
        ================ ============= ========= ========= ============ ============
        Feature          diskcache     dbm       shelve    sqlitedict   pickleDB
        ================ ============= ========= ========= ============ ============
        Atomic?          Always        Maybe     Maybe     Maybe        No
        Persistent?      Yes           Yes       Yes       Yes          Yes
        Thread-safe?     Yes           No        No        Yes          No
        Process-safe?    Yes           No        No        Maybe        No
        Backend?         SQLite        DBM       DBM       SQLite       File
        Serialization?   Customizable  None      Pickle    Customizable JSON
        Data Types?      Mapping/Deque Mapping   Mapping   Mapping      Mapping
        Ordering?        Insert/Sorted None      None      None         None
        Eviction?        LRU/LFU/more  None      None      None         None
        Vacuum?          Automatic     Maybe     Maybe     Manual       Automatic
        Transactions?    Yes           No        No        Maybe        No
        Multiprocessing? Yes           No        No        No           No
        Forkable?        Yes           No        No        No           No
        Metadata?        Yes           No        No        No           No
        ================ ============= ========= ========= ============ ============
        
        **Quality**
        
        ================ ============= ========= ========= ============ ============
        Project          diskcache     dbm       shelve    sqlitedict   pickleDB
        ================ ============= ========= ========= ============ ============
        Tests?           Yes           Yes       Yes       Yes          Yes
        Coverage?        Yes           Yes       Yes       Yes          No
        Stress?          Yes           No        No        No           No
        CI Tests?        Linux/Windows Yes       Yes       Linux        No
        Python?          2/3/PyPy      All       All       2/3          2/3
        License?         Apache2       Python    Python    Apache2      3-Clause BSD
        Docs?            Extensive     Summary   Summary   Readme       Summary
        Benchmarks?      Yes           No        No        No           No
        Sources?         GitHub        GitHub    GitHub    GitHub       GitHub
        Pure-Python?     Yes           Yes       Yes       Yes          Yes
        Server?          No            No        No        No           No
        Integrations?    Django        None      None      None         None
        ================ ============= ========= ========= ============ ============
        
        **Timings**
        
        These are rough measurements. See `DiskCache Cache Benchmarks`_ for more
        rigorous data.
        
        ================ ============= ========= ========= ============ ============
        Project          diskcache     dbm       shelve    sqlitedict   pickleDB
        ================ ============= ========= ========= ============ ============
        get                      25 µs     36 µs     41 µs       513 µs        92 µs
        set                     198 µs    900 µs    928 µs       697 µs     1,020 µs
        delete                  248 µs    740 µs    702 µs     1,717 µs     1,020 µs
        ================ ============= ========= ========= ============ ============
        
        Caching Libraries
        .................
        
        * `joblib.Memory`_ provides caching functions and works by explicitly saving
          the inputs and outputs to files. It is designed to work with non-hashable and
          potentially large input and output data types such as numpy arrays.
        * `klepto`_ extends Python’s `lru_cache` to utilize different keymaps and
          alternate caching algorithms, such as `lfu_cache` and `mru_cache`. Klepto
          uses a simple dictionary-sytle interface for all caches and archives.
        
        .. _`klepto`: https://pypi.org/project/klepto/
        .. _`joblib.Memory`: https://joblib.readthedocs.io/en/latest/memory.html
        
        Data Structures
        ...............
        
        * `dict`_ is a mapping object that maps hashable keys to arbitrary
          values. Mappings are mutable objects. There is currently only one standard
          Python mapping type, the dictionary.
        * `pandas`_ is a Python package providing fast, flexible, and expressive data
          structures designed to make working with “relational” or “labeled” data both
          easy and intuitive.
        * `Sorted Containers`_ is an Apache2 licensed sorted collections library,
          written in pure-Python, and fast as C-extensions. Sorted Containers
          implements sorted list, sorted dictionary, and sorted set data types.
        
        .. _`dict`: https://docs.python.org/3/library/stdtypes.html#typesmapping
        .. _`pandas`: https://pandas.pydata.org/
        .. _`Sorted Containers`: http://www.grantjenks.com/docs/sortedcontainers/
        
        Pure-Python Databases
        .....................
        
        * `ZODB`_ supports an isomorphic interface for database operations which means
          there's little impact on your code to make objects persistent and there's no
          database mapper that partially hides the datbase.
        * `CodernityDB`_ is an open source, pure-Python, multi-platform, schema-less,
          NoSQL database and includes an HTTP server version, and a Python client
          library that aims to be 100% compatible with the embedded version.
        * `TinyDB`_ is a tiny, document oriented database optimized for your
          happiness. If you need a simple database with a clean API that just works
          without lots of configuration, TinyDB might be the right choice for you.
        
        .. _`ZODB`: http://www.zodb.org/
        .. _`CodernityDB`: https://pypi.org/project/CodernityDB/
        .. _`TinyDB`: https://tinydb.readthedocs.io/
        
        Object Relational Mappings (ORM)
        ................................
        
        * `Django ORM`_ provides models that are the single, definitive source of
          information about data and contains the essential fields and behaviors of the
          stored data. Generally, each model maps to a single SQL database table.
        * `SQLAlchemy`_ is the Python SQL toolkit and Object Relational Mapper that
          gives application developers the full power and flexibility of SQL. It
          provides a full suite of well known enterprise-level persistence patterns.
        * `Peewee`_ is a simple and small ORM. It has few (but expressive) concepts,
          making it easy to learn and intuitive to use. Peewee supports Sqlite, MySQL,
          and PostgreSQL with tons of extensions.
        * `SQLObject`_ is a popular Object Relational Manager for providing an object
          interface to your database, with tables as classes, rows as instances, and
          columns as attributes.
        * `Pony ORM`_ is a Python ORM with beautiful query syntax. Use Python syntax
          for interacting with the database. Pony translates such queries into SQL and
          executes them in the database in the most efficient way.
        
        .. _`Django ORM`: https://docs.djangoproject.com/en/dev/topics/db/
        .. _`SQLAlchemy`: https://www.sqlalchemy.org/
        .. _`Peewee`: http://docs.peewee-orm.com/
        .. _`dataset`: https://dataset.readthedocs.io/
        .. _`SQLObject`: http://sqlobject.org/
        .. _`Pony ORM`: https://ponyorm.com/
        
        SQL Databases
        .............
        
        * `SQLite`_ is part of Python's standard library and provides a lightweight
          disk-based database that doesn’t require a separate server process and allows
          accessing the database using a nonstandard variant of the SQL query language.
        * `MySQL`_ is one of the world’s most popular open source databases and has
          become a leading database choice for web-based applications. MySQL includes a
          standardized database driver for Python platforms and development.
        * `PostgreSQL`_ is a powerful, open source object-relational database system
          with over 30 years of active development. Psycopg is the most popular
          PostgreSQL adapter for the Python programming language.
        * `Oracle DB`_ is a relational database management system (RDBMS) from the
          Oracle Corporation. Originally developed in 1977, Oracle DB is one of the
          most trusted and widely used enterprise relational database engines.
        * `Microsoft SQL Server`_ is a relational database management system developed
          by Microsoft. As a database server, it stores and retrieves data as requested
          by other software applications.
        
        .. _`SQLite`: https://docs.python.org/3/library/sqlite3.html
        .. _`MySQL`: https://dev.mysql.com/downloads/connector/python/
        .. _`PostgreSQL`: http://initd.org/psycopg/
        .. _`Oracle DB`: https://pypi.org/project/cx_Oracle/
        .. _`Microsoft SQL Server`: https://pypi.org/project/pyodbc/
        
        Other Databases
        ...............
        
        * `Memcached`_ is free and open source, high-performance, distributed memory
          object caching system, generic in nature, but intended for use in speeding up
          dynamic web applications by alleviating database load.
        * `Redis`_ is an open source, in-memory data structure store, used as a
          database, cache and message broker. It supports data structures such as
          strings, hashes, lists, sets, sorted sets with range queries, and more.
        * `MongoDB`_ is a cross-platform document-oriented database program. Classified
          as a NoSQL database program, MongoDB uses JSON-like documents with
          schema. PyMongo is the recommended way to work with MongoDB from Python.
        * `LMDB`_ is a lightning-fast, memory-mapped database. With memory-mapped
          files, it has the read performance of a pure in-memory database while
          retaining the persistence of standard disk-based databases.
        * `BerkeleyDB`_ is a software library intended to provide a high-performance
          embedded database for key/value data. Berkeley DB is a programmatic toolkit
          that provides built-in database support for desktop and server applications.
        * `LevelDB`_ is a fast key-value storage library written at Google that
          provides an ordered mapping from string keys to string values. Data is stored
          sorted by key and users can provide a custom comparison function.
        
        .. _`Memcached`: https://pypi.org/project/python-memcached/
        .. _`MongoDB`: https://api.mongodb.com/python/current/
        .. _`Redis`: https://redis.io/clients#python
        .. _`LMDB`: https://lmdb.readthedocs.io/
        .. _`BerkeleyDB`: https://pypi.org/project/bsddb3/
        .. _`LevelDB`: https://plyvel.readthedocs.io/
        
        Reference
        ---------
        
        * `DiskCache Documentation`_
        * `DiskCache at PyPI`_
        * `DiskCache at GitHub`_
        * `DiskCache Issue Tracker`_
        
        .. _`DiskCache Documentation`: http://www.grantjenks.com/docs/diskcache/
        .. _`DiskCache at PyPI`: https://pypi.python.org/pypi/diskcache/
        .. _`DiskCache at GitHub`: https://github.com/grantjenks/python-diskcache/
        .. _`DiskCache Issue Tracker`: https://github.com/grantjenks/python-diskcache/issues/
        
        License
        -------
        
        Copyright 2016-2019 Grant Jenks
        
        Licensed under the Apache License, Version 2.0 (the "License"); you may not use
        this file except in compliance with the License.  You may obtain a copy of the
        License at
        
            http://www.apache.org/licenses/LICENSE-2.0
        
        Unless required by applicable law or agreed to in writing, software distributed
        under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
        CONDITIONS OF ANY KIND, either express or implied. See the License for the
        specific language governing permissions and limitations under the License.
        
        .. _`DiskCache`: http://www.grantjenks.com/docs/diskcache/
        
Platform: UNKNOWN
Classifier: Development Status :: 5 - Production/Stable
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: Apache Software License
Classifier: Natural Language :: English
Classifier: Programming Language :: Python
Classifier: Programming Language :: Python :: 2
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.4
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
Classifier: Programming Language :: Python :: Implementation :: CPython
Classifier: Programming Language :: Python :: Implementation :: PyPy
