How to Write a Generic Cache in Go

Use a sync.Map or a map protected by a sync.RWMutex to create a thread-safe generic cache in Go. The sync.Map is optimized for high concurrency with distinct keys, while a mutex-protected map offers better performance for frequent updates or iteration.

package main

import (
	"fmt"
	"sync"
)

type Cache[K comparable, V any] struct {
	m sync.Map
}

func (c *Cache[K, V]) Get(key K) (V, bool) {
	if v, ok := c.m.Load(key); ok {
		return v.(V), true
	}
	var zero V
	return zero, false
}

func (c *Cache[K, V]) Set(key K, value V) {
	c.m.Store(key, value)
}

func (c *Cache[K, V]) Delete(key K) {
	c.m.Delete(key)
}

func main() {
	cache := &Cache[string, int]{}
	cache.Set("count", 42)
	if val, ok := cache.Get("count"); ok {
		fmt.Println(val) // 42
	}
}

A generic cache is a reusable storage container that holds data of any type, like a digital filing cabinet that accepts both letters and photos. It matters because it lets you write one caching system that works for strings, numbers, or complex objects without rewriting code. You use it when you need to store frequently accessed data in memory to speed up your application.