opticache 0.1.4

A caching library with pluggable eviction strategies

opticache

A Python caching library with pluggable eviction strategies.

Installation

pip install opticache

Usage

from opticache import Cache
from opticache.strategies import (
    LRUStrategy,
    LFUStrategy,
    FIFOStrategy,
    FIFOStrategyFastDelete,
    RandomStrategy,
    SIEVEStrategy,
)

cache_lru = Cache(LRUStrategy, capacity=500)
cache_lfu = Cache(LFUStrategy, capacity=500)
cache_fifo = Cache(FIFOStrategy, capacity=500)
cache_sieve = Cache(SIEVEStrategy, capacity=500)

cache_lru.set(key, value)
cache_lru[key] = value
cache_lru.get(key)
value = cache_lru[key]

cache_lru.delete(key)

cache_lru.clear()

for i in cache_lru:
    print(i)


@cache_lru.memoize()
def foo(x):
    return x * 2


foo(10)  # Cache miss, computes result
foo(10)  # Cache hit, returns cached result

Custom strategy

Implement the EvictionStrategy ABC to create your own:

from opticache.strategies.base import EvictionStrategy


class MyStrategy(EvictionStrategy):
    def add(self, key):
        """Track a new key."""
        ...

    def access(self, key):
        """Update tracking when a key is accessed."""
        ...

    def evict(self):
        """Return the key to evict."""
        ...

    def remove(self, key):
        """Remove a key from tracking (manual delete)."""
        ...


from opticache import Cache

cache = Cache(MyStrategy, capacity=1000)

Strategies

Strategy	Evicts	Best for
LRUStrategy	Least recently used key	General purpose, rapidly changing access patterns
LFUStrategy	Least frequently used key	Stable popularity distributions (e.g. Zipf)
FIFOStrategy	Oldest key	Simple workloads, high throughput
FIFOStrategyFastDelete	Oldest key	FIFO with frequent cache.delete() calls
RandomStrategy	Random key	Unpredictable access patterns, low overhead
SIEVEStrategy	Unvisited key via moving hand	Web caches, CDNs, filtering one-hit wonders

See the Github repository for more details and tests.