oslo.cache/doc/source/user/usage.rst

Usage

A simple example of oslo.cache in use:

from oslo_cache import core as cache
from oslo_config import cfg

CONF = cfg.CONF

caching = cfg.BoolOpt('caching', default=True)
cache_time = cfg.IntOpt('cache_time', default=3600)
CONF.register_opts([caching, cache_time], "feature-name")

cache.configure(CONF)
example_cache_region = cache.create_region()
MEMOIZE = cache.get_memoization_decorator(
    CONF, example_cache_region, "feature-name")

# Load config file here

cache.configure_cache_region(CONF, example_cache_region)


@MEMOIZE
def f(x):
    print(x)
    return x

An example config file for this is:

[cache]
enabled = true
backend = dogpile.cache.memory

[feature-name]
caching = True
cache_time = 7200

There is some subtlety in the order of the calls in the example above. The requirements are: configure must be done first; create_region must be before both get_memoization_decorator and configure_cache_region (because they use the output); the config file must be fully loaded before configure_cache_region is called; all these calls must complete before a decorated function is actually invoked. In principle, there are several different orders this can happen in. In practice, the decorator will be used at import time, and the config file will be loaded later, so the above order is the only possible one.