A caching library for Python.
- Project: https://github.com/dgilland/cacheout
- Documentation: https://cacheout.readthedocs.io
- PyPI: https://pypi.python.org/pypi/cacheout/
- Github Actions: https://github.com/dgilland/cacheout/actions
- In-memory caching using dictionary backend
- Cache manager for easily accessing multiple cache objects
- Reconfigurable cache settings for runtime setup when using module-level cache objects
- Maximum cache size enforcement
- Default cache TTL (time-to-live) as well as custom TTLs per cache entry
- Bulk set, get, and delete operations
- Bulk get and delete operations filtered by string, regex, or function
- Memoization decorators
- Thread safe
- Multiple cache implementations:
- FIFO (First In, First Out)
- LIFO (Last In, First Out)
- LRU (Least Recently Used)
- MRU (Most Recently Used)
- LFU (Least Frequently Used)
- RR (Random Replacement)
- Layered caching (multi-level caching)
- Python >= 3.7
Install using pip:
pip install cacheout
Let's start with some basic caching by creating a cache object:
from cacheout import Cache
cache = Cache()By default the cache object will have a maximum size of 256, default TTL (time-to-live) expiration turned off, TTL timer that uses time.time (meaning TTL is in seconds), and the default for missing keys as None. These values can be set with:
cache = Cache(maxsize=256, ttl=0, timer=time.time, default=None) # defaultsSet a cache key using cache.set():
cache.set(1, 'foobar')Get the value of a cache key with cache.get():
assert cache.get(1) == 'foobar'Get a default value when cache key isn't set:
assert cache.get(2) is None
assert cache.get(2, default=False) is False
assert 2 not in cacheProvide cache values using a default callable:
assert 2 not in cache
assert cache.get(2, default=lambda key: key) == 2
assert cache.get(2) == 2
assert 2 in cacheProvide a global default:
cache2 = Cache(default=True)
assert cache2.get('missing') is True
assert 'missing' not in cache2
cache3 = Cache(default=lambda key: key)
assert cache3.get('missing') == 'missing'
assert 'missing' in cache3Set the TTL (time-to-live) expiration per entry (default TTL units are in seconds when Cache.timer is set to the default time.time; otherwise, the units are determined by the custom timer function):
cache.set(3, {'data': {}}, ttl=1)
assert cache.get(3) == {'data': {}}
time.sleep(1)
assert cache.get(3) is NoneMemoize a function where cache keys are generated from the called function parameters:
@cache.memoize()
def func(a, b):
passProvide a TTL for the memoized function and incorporate argument types into generated cache keys:
@cache.memoize(ttl=5, typed=True)
def func(a, b):
pass
# func(1, 2) has different cache key than func(1.0, 2.0), whereas,
# with "typed=False" (the default), they would have the same keyAccess the original memoized function:
@cache.memoize()
def func(a, b):
pass
func.uncached(1, 2)Get a copy of the entire cache with cache.copy():
assert cache.copy() == {1: 'foobar', 2: ('foo', 'bar', 'baz')}Delete a cache key with cache.delete():
cache.delete(1)
assert cache.get(1) is NoneClear the entire cache with cache.clear():
cache.clear()
assert len(cache) == 0Perform bulk operations with cache.set_many(), cache.get_many(), and cache.delete_many():
cache.set_many({'a': 1, 'b': 2, 'c': 3})
assert cache.get_many(['a', 'b', 'c']) == {'a': 1, 'b': 2, 'c': 3}
cache.delete_many(['a', 'b', 'c'])
assert cache.count() == 0Use complex filtering in cache.get_many() and cache.delete_many():
import re
cache.set_many({'a_1': 1, 'a_2': 2, '123': 3, 'b': 4})
cache.get_many('a_*') == {'a_1': 1, 'a_2': 2}
cache.get_many(re.compile(r'\d')) == {'123': 3}
cache.get_many(lambda key: '2' in key) == {'a_2': 2, '123': 3}
cache.delete_many('a_*')
assert dict(cache.items()) == {'123': 3, 'b': 4}Reconfigure the cache object after creation with cache.configure():
cache.configure(maxsize=1000, ttl=5 * 60)Get keys, values, and items from the cache with cache.keys(), cache.values(), and cache.items():
cache.set_many({'a': 1, 'b': 2, 'c': 3})
assert list(cache.keys()) == ['a', 'b', 'c']
assert list(cache.values()) == [1, 2, 3]
assert list(cache.items()) == [('a', 1), ('b', 2), ('c', 3)]Iterate over cache keys:
for key in cache:
print(key, cache.get(key))
# 'a' 1
# 'b' 2
# 'c' 3Check if key exists with cache.has() and key in cache:
assert cache.has('a')
assert 'a' in cacheUse callbacks to be notified of on-get, on-set, and on-delete events:
def on_get(key, value, exists):
pass
def on_set(key, new_value, old_value):
pass
def on_delete(key, value, cause):
passEnable cache statistics:
cache_with_stats = Cache(enable_stats=True)
# Or via configure()
cache.configure(enable_stats=True)
# Or directly via Cache.stats
cache.stats.enable()Get cache statistics:
print(cache.stats.info())Manage tracking of statistics:
# Pause tracking (collected stats will not be affected)
cache.stats.pause()
# Resume tracking
cache.stats.resume()
# Reset stats
cache.stats.reset()
# Disable stats (WARNING: This resets stats)
cache.stats.disable()
# Disable via configure() (WARNING: This resets stats)
cache.configure(enable_stats=False)Manage multiple caches using CacheManager:
from cacheout import CacheManager
cacheman = CacheManager({'a': {'maxsize': 100},
'b': {'maxsize': 200, 'ttl': 900},
'c': {})
cacheman['a'].set('key1', 'value1')
value = cacheman['a'].get('key')
cacheman['b'].set('key2', 'value2')
assert cacheman['b'].maxsize == 200
assert cacheman['b'].ttl == 900
cacheman['c'].set('key3', 'value3')
cacheman.clear_all()
for name, cache in cacheman:
assert name in cacheman
assert len(cache) == 0For more details, see the full documentation at https://cacheout.readthedocs.io.