Local Cache Implementation

This repository contains an implementation of a local cache using a hash map and a doubly linked list. The cache utilizes time-to-live (TTL) to delete expired values and implements a Least-Recently-Used (LRU) policy to evict values in case the cache is full.

Additionally, a background cleaner has been implemented to periodically clear out expired values from the cache. This can be enabled by properly configuring the LocalStorage:

config := glocalstorage.StorageConfig{
    Expiration: 24 * time.Hour,
    Capacity:   100,
    CleanupInterval: 1 * time.Hour, // Cleanup runs in the background every hour
}

If the CleanupInterval is set to 0, the BackgroundCleaner goroutine will not be fired. Hence, this can in a higher memory usage becuase items will not be deleted until they are queried (using cache.Get) or until the LRU policy decides to evict an expired item.

Features

• StorageConfig Struct: Defines configuration parameters such as expiration time and capacity for the cache.
• LocalStorage Struct: Represents the local cache with methods for setting, getting, deleting, clearing, and displaying cache contents.
• Node Struct: Represents a node in the cache with key, value, expiration time, and pointers to the next and previous nodes.
• New Function: Initializes a new local cache with the given configuration.
• Set Method: Inserts a key-value pair into the cache, updating the expiration time and handling eviction if necessary. If a -1 itemExpiration is passed the cache item follows the default expiration; if a 0 itemExpiration is passed the cache item never expires; if > 0 itemExpiration is passed the cache item will its own default expiration.
• Get Method: Retrieves a value from the cache based on the given key, updating its access time.
• Delete Method: Removes a key-value pair from the cache.
• Clear Method: Clears all entries in the cache.
• Show Method: Displays the contents of the cache.

Usage

To use this local cache implementation, follow these steps:

1. Import the g-local-storage package.
2. Initialize a new cache with the desired configuration using the New function. Use the Set, Get, Delete, Clear, and Show methods to interact with the cache.

import (
    "fmt"
    "github.com/ScovottoDavide/g-local-storage"
    "time"
)

func main() {
    config := glocalstorage.StorageConfig{
        Expiration: 24 * time.Hour, // if set to 0, items cache will never expire
        Capacity:   100,
        CleanupInterval: 1 * time.Hour, // Cleanup runs in the background every hour
    }

    cache := glocalstorage.New(config)

    cache.Set("key", []byte("value"))
    value, _ := cache.Get("key")
    fmt.Println("Retrieved value:", string(value))
}