Getting started

Instantiating a Cache

Both sync and async Caches requires at least these parameters to work:

• backend: functions as a storage
• serializer: is responsible for converting actual values from and to something that a backend would be able to store

Cache may be annotated with a value type like this Cache[ValueT, WireT], which provides type hints for the cache methods.

Instantiating a backend

There are a few ways to instantiate a backend:

• By directly instantiating a backend class via its __init__()
• By instantiating a specific backend class via its from_url() class method. In that case the URL is forwarded to underlying client (if any)
• By using cachetory.[sync|async_].from_url() function. In that case specific backend class is chosen by the URL's scheme, and the URL is forwarded to its from_url() class method. This is especially useful to configure an arbitrary backend from a single configuration option – instead of hard-coding a specific backend class.

Examples

import redis
import cachetory.backends.sync
import cachetory.backends.async_

backend = cachetory.backends.sync.from_url("memory://")
backend = cachetory.backends.async_.from_url("dummy://")
backend = cachetory.backends.sync.RedisBackend(redis.Redis(...))
backend = cachetory.backends.async_.from_url("redis://localhost:6379/1")

Instantiating a serializer

Instantiating of a serializer is very much similar to that of a backend. To instantiate it by a URL use cachetory.serializers.from_url() – unlike the back-end case there are no separate sync and async versions.

Scheme joining

cachetory.serializers.from_url() supports scheme joining with +, as in pickle+zlib://. In that case multiple serializers are instantiated and applied sequentially (in the example a value would be serialized by pickle and the serialized value is then compressed by zlib). Deserialization order is, of course, the opposite.

Examples

import pickle

import cachetory.serializers

serializer = cachetory.serializers.from_url("pickle+zstd://")
serializer = cachetory.serializers.from_url(
    "pickle+zstd://?pickle-protocol=4&compression-level=3",
)
serializer = cachetory.serializers.from_url("null://")
serializer = cachetory.serializers.NoopSerializer()
serializer = cachetory.serializers.PickleSerializer(
    pickle_protocol=pickle.DEFAULT_PROTOCOL,
)

cachetory.serializers.from_url

from_url(url: str) -> Serializer[ValueT, WireT]

Construct a serializer from the URL.

This is an alias for the cachetory.serializers.ChainedSerializer.from_url().

Source code in cachetory/serializers/__init__.py

def from_url(url: str) -> Serializer[ValueT, WireT]:
    """
    Construct a serializer from the URL.

    This is an alias for the
    [`cachetory.serializers.ChainedSerializer.from_url()`][cachetory.serializers.ChainedSerializer.from_url].
    """
    return ChainedSerializer[ValueT, WireT].from_url(url)