Crate fncache 

fncache

A zero-boilerplate Rust library for function-level caching with pluggable backends, inspired by functools.lru_cache and request-cache.

Features

• Zero Boilerplate: Simple #[fncache] attribute for instant caching
• Pluggable Backends: Memory, File, Redis, RocksDB support
• Async/Sync: Seamless support for both synchronous and asynchronous functions
• Type Safety: Strong typing throughout the caching layer with compile-time guarantees
• Advanced Metrics: Built-in instrumentation with latency, hit rates, and size tracking
• Cache Invalidation: Tag-based and prefix-based cache invalidation
• Background Warming: Proactive cache population for improved performance

Quick Start

// Example usage (not actually run in tests due to proc-macro limitations)
use fncache::{fncache, init_global_cache, MemoryBackend};

// Initialize the global cache with an in-memory backend
init_global_cache(MemoryBackend::new()).unwrap();

#[fncache(ttl = 60)] // Cache for 60 seconds
fn expensive_operation(x: u64) -> u64 {
    println!("Performing expensive operation for {}", x);
    x * x
}

fn main() {
    // First call executes the function
    let result1 = expensive_operation(5);
    println!("Result 1: {}", result1); // Takes time
     
    // Second call returns cached result
    let result2 = expensive_operation(5);
    println!("Result 2: {}", result2); // Returns immediately
}

Re-exports

pub use error::Error as FncacheError;

pub use backends::memory::MemoryBackend;

Modules

backends

Backend implementations for different storage systems.

error

Error types for the fncache library.

eviction

Eviction policy implementations.

invalidation

Cache Invalidation

key_derivation

Key derivation strategies for cache keys

metrics

Metrics collection for cache operations.

prelude

Common prelude for using the library.

serialization

Serialization support for fncache.

warming

Background cache warming implementation.

Structs

GlobalCache

Internal structure to hold the cache backend

Functions

global_cache

Get a reference to the global cache (test version).

init_global_cache

Initialize the global cache with the specified backend (test version).

reset_global_cache_for_testing

Reset the global cache for testing purposes.

Type Aliases

Result

The main cache result type.

Attribute Macros

fncache

Re-export of the proc macro for convenience.