Simple In-Memory Key-Value Store in Go with Concurrency Handling

Creating a key-value store in Go (Golang) can be a fun and educational project. Below is a simple implementation of an in-memory key-value store. This basic implementation includes functions to set, get, and delete key-value pairs. It uses a map as the underlying data structure and includes mutex synchronization to handle concurrent access.

package main

import (
	"fmt"
	"sync"
)

// KVStore represents a key-value store.
type KVStore struct {
	store map[string]interface{}
	mu    sync.RWMutex
}

// NewKVStore creates a new KVStore.
func NewKVStore() *KVStore {
	return &KVStore{
		store: make(map[string]interface{}),
	}
}

// Set adds a key-value pair to the store.
func (kv *KVStore) Set(key string, value interface{}) {
	kv.mu.Lock()
	defer kv.mu.Unlock()
	kv.store[key] = value
}

// Get retrieves a value by key from the store.
func (kv *KVStore) Get(key string) (interface{}, bool) {
	kv.mu.RLock()
	defer kv.mu.RUnlock()
	value, exists := kv.store[key]
	return value, exists
}

// Delete removes a key-value pair from the store.
func (kv *KVStore) Delete(key string) {
	kv.mu.Lock()
	defer kv.mu.Unlock()
	delete(kv.store, key)
}

func main() {
	// Create a new key-value store
	store := NewKVStore()

	// Set some key-value pairs
	store.Set("name", "Alice")
	store.Set("age", 30)

	// Retrieve a value
	if value, exists := store.Get("name"); exists {
		fmt.Println("Name:", value)
	} else {
		fmt.Println("Name not found")
	}

	// Delete a key-value pair
	store.Delete("name")

	// Try to retrieve the deleted key
	if value, exists := store.Get("name"); exists {
		fmt.Println("Name:", value)
	} else {
		fmt.Println("Name not found")
	}
}

Explanation:

1. KVStore Structure: The KVStore struct contains the map which holds the key-value pairs and an sync.RWMutex to handle concurrent access.

2. NewKVStore Function: This function initializes and returns a new KVStore.

3. Set Method: Adds a key-value pair to the store. It locks the store to prevent concurrent write operations.

4. Get Method: Retrieves the value associated with a given key. It uses a read lock to allow concurrent read access but prevent write access during the read operation.

5. Delete Method: Removes a key-value pair from the store. It locks the store to prevent concurrent write operations.

6. Main Function: Demonstrates how to use the key-value store by setting, getting, and deleting key-value pairs.

This example is simple and does not cover persistence, eviction, or other advanced features found in production-ready key-value stores.