caching 0.1.dev1

Python utils and decorators for cаching with TTL, maxsize and file-based storage.

Status

WORK IN PROGRESS

Caching

Python utils and decorators for cаching with TTL, maxsize and file-based storage.

Installation

pip install caching

Usage

from caching import cache

@cache(ttl=60, maxsize=128, filepath='/tmp/mycache')
def long_running_function(a, b, *args, c=None, **kwargs):
    pass

Advanced usage

from caching import Cache

# Set default parameters

cache = Cache(filepath='/tmp/mycache', ttl=3600, maxsize=1024)

# Use default parameters

@cache
def pow(x, y):
    return x**y

# Override default parameters

@cache(filepath=None, ttl=-1, maxsize=10000)
def factorial(n):
    if n == 0:
        return 1
    return n * factorial(n-1)

def cache_key(x):
    return str(x)

@cache(ttl=-1, maxsize=10000, key=cache_key)
def toupper(a):
    return str(a).upper()

# Using cache as a key-value store

try:
    result = cache[1]
except KeyError:
    result = calculate_result(1)
    cache[1] = result
    assert 1 in cache
    assert cache[1] == result
    assert cache.get(1, None) == result
    assert cache.get(2, None) is None

# Cleanup

import os

cache = Cache(filepath='/tmp/mycache')
cache[1] = 'one'
assert 1 in cache
cache.clear()  # empty the cache
assert 1 not in cache
assert list(cache.items()) == []
assert os.path.isfile('/tmp/mycache')
cache.remove()  # Empty the cache and remove the underlying file
assert not os.path.isfile('/tmp/mycache')

Features

• [x] Memory and file based cache.

• [x] TTL and maxsize.

• [x] Works with *args, **kwargs.

• [x] Works with mutable function arguments of the following types: dict, list, set.

• [ ] LRS (least recently stored), LRU and LFU cache.

• [ ] Multiprocessing- and thread-safe.

• [ ] Customizable cache key function.

• [ ] Pluggable external caching backends (see Redis example).