Scrooge Cache

What is Scrooge?

Scrooge is a Smart Cache Storage for stronger gentlemen

Backend supports:

• memcache
• redis

How can I use?

Scrooge is able to cache function returns based on its input arguments for a given time.

Rules:

• Just a unique namespace per backend instance;
• If you do not set expiration_time scrooge will take infinite time;
• The return of decorated function must be str or int or float or tuple, or list or dict;
• If you use redis backend you can defined the db index using the parameter db=index, if you do not do this the default will be 0;

Installing

pip install scrooge-cache

Quick start

Using with redis as backend

This example below will cache the function return for an undetermined time

import time
from scrooge import RedisBackend, Client

backend = RedisBackend(host='127.0.0.1', port=6379)
client = Client(cache_backend=backend)

# Cached for an undetermined time
@client.gentlemen_cache(namespace='f1')
def function_to_be_cached(p1, p2):
    time.sleep(5)
    return {"p1": p1, "p2": p2}

# After 5 seconds the return will be {"p1": 4, "p2": 5}
print(function_to_be_cached(4,5))

# The return will be {"p1": 4, "p2": 5}
print(function_to_be_cached(4,5))

This example below will cache the function return for 10 seconds

import time
from scrooge import RedisBackend, Client

backend = RedisBackend(host='127.0.0.1', port=6379)
client = Client(cache_backend=backend)

# Cached for 10 seconds
@client.gentlemen_cache(namespace='f1', expiration_time=10)
def function_to_be_cached(p1, p2):
    time.sleep(5)
    return {"p1": p1, "p2": p2}

# After 5 seconds the return will be {"p1": 4, "p2": 5}
print(function_to_be_cached(4,5))

# The return will be {"p1": 4, "p2": 5}
print(function_to_be_cached(4,5))

time.sleep(5)

# After 5 seconds the return will be {"p1": 4, "p2": 5}
print(function_to_be_cached(4,5))

Using with memcache as backend

This example below will cache the function return for an undetermined time

import time
from scrooge import MemcacheBackend, Client

backend = MemcacheBackend(host='127.0.0.1', port=11211)
client = Client(cache_backend=backend)

# Cached for an undetermined time
@client.gentlemen_cache(namespace='f1')
def function_to_be_cached(p1, p2):
    time.sleep(5)
    return {"p1": p1, "p2": p2}

# After 5 seconds the return will be {"p1": 4, "p2": 5}
print(function_to_be_cached(4,5))

# The return will be {"p1": 4, "p2": 5}
print(function_to_be_cached(4,5))

This example below will cache the function return for 10 seconds

import time
from scrooge import MemcacheBackend, Client

backend = MemcacheBackend(host='127.0.0.1', port=11211)
client = Client(cache_backend=backend)

# Cached for 10 seconds
@client.gentlemen_cache(namespace='f1', expiration_time=10)
def function_to_be_cached(p1, p2):
    time.sleep(5)
    return {"p1": p1, "p2": p2}

# After 5 seconds the return will be {"p1": 4, "p2": 5}
print(function_to_be_cached(4,5))

# The return will be {"p1": 4, "p2": 5}
print(function_to_be_cached(4,5))

time.sleep(5)

# After 5 seconds the return will be {"p1": 4, "p2": 5}
print(function_to_be_cached(4,5))

No caching

If you wanna a cacheless request, you can do this using the no_cache argument

import time
from scrooge import MemcacheBackend, Client

backend = MemcacheBackend(host='127.0.0.1', port=11211)
client = Client(cache_backend=backend)

# Cached for 10 seconds
@client.gentlemen_cache(namespace='f1', expiration_time=10)
def function_to_be_cached(p1, p2):
    time.sleep(5)
    return {"p1": p1, "p2": p2}

# After 5 seconds the return will be {"p1": 4, "p2": 5}
print(function_to_be_cached(4,5))

# Cacheless request below
# After 5 seconds the return will be {"p1": 4, "p2": 5}
print(function_to_be_cached(4,5, no_cache=True))

Force cache update

If you wanna force the cache update, you can do this using the force_cache_update argument

import time
from scrooge import MemcacheBackend, Client

backend = MemcacheBackend(host='127.0.0.1', port=11211)
client = Client(cache_backend=backend)

# Cached for 10 seconds
@client.gentlemen_cache(namespace='f1', expiration_time=10)
def function_to_be_cached(p1, p2):
    time.sleep(5)
    return {"p1": p1, "p2": p2}

# After 5 seconds the return will be {"p1": 4, "p2": 5}
print(function_to_be_cached(4,5))

# Force cache update
# After 5 seconds the return will be {"p1": 4, "p2": 5}
print(function_to_be_cached(4,5, force_cache_update=True))

Run tests

pytest -ra