dcache

from dcache import dcache

@dcache
def slow_function(n):
    return n ** 1000

dcache vs redis

import redis
redis = redis.Redis(host='localhost', port=6379, db=0)

def slow_function(n):
    cached = redis.get(n)
    if cached:
        return cached
    value = n ** 1000
    redis.set(n, value)
    return value

def slow_function2(n):
    cached = redis.get(n)
    if cached:
        return cached
    value = n ** 1000
    redis.set(n, value)
    return value

from dcache import cache
from dcache.backends import RedisBackend

cache = dcache(RedisBackend(host='localhost', port=6379, db=0))

@cache
def slow_function(n):
    return n ** 1000

@cache
def slow_function2(n):
    return n ** 1000

real example

def process(id, input):
    cache_path = get_content_cache_path(id, input)

    if resource.file_exist(cache_path):
        return resource.get_json(cache_path)

    response = slow_function(id, input)
      resource.put_json(body=response, file_path=cache_path)
    return response

from dcache import dcache
from dcache.backends import S3Backend

@dcache(S3Backend())
def process(id, input):
    return slow_function(id, input)

multiple backends

from dcache import dcache
from dcache.backends import InMemoryBackend, RedisBackend

@dcache(multiple=[
    InMemoryBackend(),
    RedisBackend(host='localhost', port=6379, db=0),
])
def slow_function(n):
        return n ** 1000

1. search on the in-memory cache;

2. if exists, return, if not, search on Redis;

3. • if exists on Redis, save in memory and return;

4. • if not, exists on Redis, run the slow_function, save on Redis, save in-memory and return;

• doesn’t run if already returned