pyfastlru 1.0.0

Python implementation of a thread-safe LRU cache.

pyfastlru v. 1.0

Python implementation of a thread-safe LRU cache.

Features: thread safety, statistics, familiar interface.

The MIT License (MIT). Copyright © 2025 Anatoly Petrov [e-mail]

Description

LRU cache is a data structure that combines fast item access by the key with invalidation of least recently used items in case of size limit exhaustion.

These traits make the LRU cache useful for memoizing some computations (requests, resources, etc.) without risking memory blowup.

Our implementation uses a doubly linked list for item usage tracking and a dict for the lookup table.

Overview

The cache provides a MutableMapping interface. Thus, you may use LruCache the same way you use dict.

Unlike the standard dict (which is unbounded), the cache size is limited by the maxsize value provided to the cache __init__ method (128 by default). If the item count exceeds the limit,LruCache automatically removes the least recently used item.

Synchronization is performed internally by the cache with a reentrant lock and doesn't require any actions from the end-user.

Manual synchronization with LruCache context protocol or acquire/release methods is needed only to implement the atomic operations.

Cache collects usage statistics (hits, misses, maxsize, currsize) which may be retrieved with the cache_info() method.

Testing

pyfastlru is tested with pytest framework.

License

pyfastlru is licensed under the MIT License, see LICENSE for more information.