Dependency Cache

:construction: Work In Progress :construction:

Description

A library for managing the caching of an object's methods with cache invalidation handled by a dependency graph. Instead of recomputing expensive, deeply nested calculations on every call, Dependency Cache stores the result and only invalidates (and recalculates) it when one of its dependencies actually changes. This project is written in rust, with pyo3, and compiled using maturin.

Installation

Install the latest stable version from PyPI:

pip install dependency-cache

API Overview

Setup

This project uses (and requires) uv as a package manager and maturin to compile.

Steps:

• install python dependencies

uv sync

• generate local development file for testing (and update pyi file for accurate typechecking)

maturin develop --generate-stubs
maturin develop -r --generate-stubs

• run python tests

uv run pytest
uv run pytest -vv

• run rust tests

cargo test

• temporary fix: generate stubs currently produces a file that is incorrectly formatted, use ruff to format the pyi file immediately

maturin develop --generate-stubs | uv run ruff format ./python/dependency_cache/dependency_cache.pyi

Quick Example

from dependency_cache import DependencyCacheBase, automagically_dependency_cached


class ExampleCalculation(DependencyCacheBase):
    """   C
        //  \\
       A      B
    """

    def __init__(self, x, y):
        super().__init__()
        self.x = x
        self.y = y

    @automagically_dependency_cached()
    def A(self):
        print("calculating A")
        return self.x

    @automagically_dependency_cached()
    def B(self):
        print("calculating B")
        return self.y

    @automagically_dependency_cached()
    def C(self):
        print("calculating C")
        return self.B() + self.A()


c = ExampleCalculation(3, 5)
print(c.C())  # calculates A, B, C -> 8
print(c.C())  # hits cache -> 8

c.update_cached_value("A", 0)  # invalidates C (but not B)
print(c.C())  # recalculates C -> 5

This example can be found here with more runnable examples and use cases provided in the python/examples folder.

uv run ./python/examples/example.py

TODOs

This project is still a work in progress, with everything from API to underlying design subject to change on my whim.

Current TODO list (in no particular order):

• scenario analysis capability
• allow input to control ordering for cache dump
• move plot_dependency_graph to rust side instead of python
• add object thread safety for python 3.14+
• work out how best to handle nested objects