Add LRU cache support.

cache/cache.go

@@ -27,6 +27,7 @@ type CacheConfig struct {
 	Memory struct {
 		MaxMemorySize int64 `json:"max_memory_size"` // Maximum memory size in bytes
 		MaxEntries    int64 `json:"max_entries"`     // Maximum number of entries
+		UseLRU        bool  `json:"use_lru"`         // Use LRU eviction algorithm instead of random eviction
 	}
 	TTL                  int  `json:"ttl"`
 	IncludeUserContext   bool `json:"include_user_context"`    // Include user ID and role in cache key
@@ -96,16 +97,6 @@ func CalculateHash(c *fiber.Ctx, userID string, userRole string) string {
 	return strutil.Md5(cacheKeyData)
 }
 
-// CalculateHashLegacy generates a cache hash using only the request body (DEPRECATED).
-// This function exists for backward compatibility only and should NOT be used
-// in production multi-user applications as it creates a security vulnerability
-// where users can see each other's cached data.
-//
-// Deprecated: Use CalculateHash with user context instead.
-func CalculateHashLegacy(c *fiber.Ctx) string {
-	return strutil.Md5(c.Body())
-}
-
 func EnableCache(cfg *CacheConfig) {
 	if cfg.Logger == nil {
 		cfg.Logger = libpack_logger.New()
@@ -134,34 +125,41 @@ func EnableCache(cfg *CacheConfig) {
 			cfg.Client = libpack_cache_redis.NewCacheWrapper(redisClient, cfg.Logger)
 		}
 	} else {
+		// Calculate memory and entry limits
+		maxMemory := cfg.Memory.MaxMemorySize
+		if maxMemory <= 0 {
+			maxMemory = libpack_cache_memory.DefaultMaxMemorySize
+		}
+
+		maxEntries := cfg.Memory.MaxEntries
+		if maxEntries <= 0 {
+			maxEntries = libpack_cache_memory.DefaultMaxCacheSize
+		}
+
+		cacheType := "standard"
+		if cfg.Memory.UseLRU {
+			cacheType = "LRU"
+		}
+
 		cfg.Logger.Debug(&libpack_logger.LogMessage{
 			Message: "Using in-memory cache",
 			Pairs: map[string]interface{}{
-				"max_memory_size_bytes": cfg.Memory.MaxMemorySize,
-				"max_entries":           cfg.Memory.MaxEntries,
+				"type":                  cacheType,
+				"max_memory_size_bytes": maxMemory,
+				"max_entries":           maxEntries,
 			},
 		})
 
-		// Use memory size and entry limits if configured, otherwise use defaults
-		if cfg.Memory.MaxMemorySize > 0 || cfg.Memory.MaxEntries > 0 {
-			maxMemory := cfg.Memory.MaxMemorySize
-			if maxMemory <= 0 {
-				maxMemory = libpack_cache_memory.DefaultMaxMemorySize
-			}
-
-			maxEntries := cfg.Memory.MaxEntries
-			if maxEntries <= 0 {
-				maxEntries = libpack_cache_memory.DefaultMaxCacheSize
-			}
-
+		if cfg.Memory.UseLRU {
+			// Use LRU cache with proper eviction algorithm
+			cfg.Client = libpack_cache_memory.NewLRUMemoryCache(maxMemory, maxEntries)
+		} else {
+			// Use standard sync.Map-based cache
 			cfg.Client = libpack_cache_memory.NewWithSize(
 				time.Duration(cfg.TTL)*time.Second,
 				maxMemory,
 				maxEntries,
 			)
-		} else {
-			// Backward compatibility
-			cfg.Client = libpack_cache_memory.New(time.Duration(cfg.TTL) * time.Second)
 		}
 	}
 	config = cfg
@@ -271,6 +269,9 @@ func CacheGetQueries() int64 {
 }
 
 func CacheClear() {
+	if !IsCacheInitialized() {
+		return
+	}
 	config.Client.Clear()
 	cacheStats = &CacheStats{}
 }

cache/memory/lru_memory_cache.go

@@ -279,3 +279,8 @@ func (c *LRUMemoryCache) GetMemoryUsage() int64 {
 func (c *LRUMemoryCache) GetMaxMemorySize() int64 {
 	return c.maxMemorySize
 }
+
+// CountQueries returns the number of entries in the cache
+func (c *LRUMemoryCache) CountQueries() int64 {
+	return atomic.LoadInt64(&c.currentCount)
+}

cache/memory/lru_memory_cache_test.go

@@ -0,0 +1,343 @@
+package libpack_cache_memory
+
+import (
+	"fmt"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/suite"
+)
+
+type LRUMemoryCacheTestSuite struct {
+	suite.Suite
+}
+
+func TestLRUMemoryCacheTestSuite(t *testing.T) {
+	suite.Run(t, new(LRUMemoryCacheTestSuite))
+}
+
+func (suite *LRUMemoryCacheTestSuite) TestNewLRUMemoryCache() {
+	cache := NewLRUMemoryCache(1024*1024, 100) // 1MB, 100 entries
+	suite.NotNil(cache)
+	suite.Equal(int64(0), cache.CountQueries())
+	suite.Equal(int64(0), cache.GetMemoryUsage())
+	suite.Equal(int64(1024*1024), cache.GetMaxMemorySize())
+}
+
+func (suite *LRUMemoryCacheTestSuite) TestSetAndGet() {
+	cache := NewLRUMemoryCache(1024*1024, 100)
+
+	// Set a value
+	cache.Set("key1", []byte("value1"), 5*time.Second)
+
+	// Get the value
+	val, found := cache.Get("key1")
+	suite.True(found)
+	suite.Equal([]byte("value1"), val)
+
+	// Get non-existent key
+	val, found = cache.Get("nonexistent")
+	suite.False(found)
+	suite.Nil(val)
+}
+
+func (suite *LRUMemoryCacheTestSuite) TestUpdateExisting() {
+	cache := NewLRUMemoryCache(1024*1024, 100)
+
+	cache.Set("key1", []byte("value1"), 5*time.Second)
+	cache.Set("key1", []byte("value2"), 5*time.Second)
+
+	val, found := cache.Get("key1")
+	suite.True(found)
+	suite.Equal([]byte("value2"), val)
+	suite.Equal(int64(1), cache.CountQueries())
+}
+
+func (suite *LRUMemoryCacheTestSuite) TestDelete() {
+	cache := NewLRUMemoryCache(1024*1024, 100)
+
+	cache.Set("key1", []byte("value1"), 5*time.Second)
+	suite.Equal(int64(1), cache.CountQueries())
+
+	cache.Delete("key1")
+	suite.Equal(int64(0), cache.CountQueries())
+
+	val, found := cache.Get("key1")
+	suite.False(found)
+	suite.Nil(val)
+
+	// Delete non-existent key should not panic
+	cache.Delete("nonexistent")
+}
+
+func (suite *LRUMemoryCacheTestSuite) TestClear() {
+	cache := NewLRUMemoryCache(1024*1024, 100)
+
+	cache.Set("key1", []byte("value1"), 5*time.Second)
+	cache.Set("key2", []byte("value2"), 5*time.Second)
+	cache.Set("key3", []byte("value3"), 5*time.Second)
+	suite.Equal(int64(3), cache.CountQueries())
+
+	cache.Clear()
+	suite.Equal(int64(0), cache.CountQueries())
+	suite.Equal(int64(0), cache.GetMemoryUsage())
+
+	_, found := cache.Get("key1")
+	suite.False(found)
+}
+
+func (suite *LRUMemoryCacheTestSuite) TestExpiration() {
+	cache := NewLRUMemoryCache(1024*1024, 100)
+
+	cache.Set("key1", []byte("value1"), 100*time.Millisecond)
+
+	// Should exist immediately
+	val, found := cache.Get("key1")
+	suite.True(found)
+	suite.Equal([]byte("value1"), val)
+
+	// Wait for expiration
+	time.Sleep(150 * time.Millisecond)
+
+	// Should be expired
+	val, found = cache.Get("key1")
+	suite.False(found)
+	suite.Nil(val)
+}
+
+func (suite *LRUMemoryCacheTestSuite) TestEvictionByCount() {
+	cache := NewLRUMemoryCache(1024*1024, 3) // Max 3 entries
+
+	cache.Set("key1", []byte("value1"), 5*time.Second)
+	cache.Set("key2", []byte("value2"), 5*time.Second)
+	cache.Set("key3", []byte("value3"), 5*time.Second)
+
+	// All 3 should exist
+	_, found := cache.Get("key1")
+	suite.True(found)
+	_, found = cache.Get("key2")
+	suite.True(found)
+	_, found = cache.Get("key3")
+	suite.True(found)
+
+	// Add 4th entry - should evict oldest (key1)
+	cache.Set("key4", []byte("value4"), 5*time.Second)
+
+	suite.Equal(int64(3), cache.CountQueries())
+
+	// key1 should be evicted (it was least recently used)
+	_, found = cache.Get("key1")
+	suite.False(found)
+
+	// Others should still exist
+	_, found = cache.Get("key2")
+	suite.True(found)
+	_, found = cache.Get("key3")
+	suite.True(found)
+	_, found = cache.Get("key4")
+	suite.True(found)
+}
+
+func (suite *LRUMemoryCacheTestSuite) TestLRUOrder() {
+	cache := NewLRUMemoryCache(1024*1024, 3) // Max 3 entries
+
+	cache.Set("key1", []byte("value1"), 5*time.Second)
+	cache.Set("key2", []byte("value2"), 5*time.Second)
+	cache.Set("key3", []byte("value3"), 5*time.Second)
+
+	// Access key1 to make it recently used
+	cache.Get("key1")
+
+	// Add key4 - should evict key2 (now least recently used)
+	cache.Set("key4", []byte("value4"), 5*time.Second)
+
+	// key2 should be evicted
+	_, found := cache.Get("key2")
+	suite.False(found)
+
+	// key1 should still exist (was accessed recently)
+	_, found = cache.Get("key1")
+	suite.True(found)
+}
+
+func (suite *LRUMemoryCacheTestSuite) TestEvictionByMemory() {
+	// Small memory limit - 500 bytes
+	cache := NewLRUMemoryCache(500, 100)
+
+	// Each entry has ~64 bytes overhead + key + value
+	cache.Set("key1", []byte("value1"), 5*time.Second)
+	cache.Set("key2", []byte("value2"), 5*time.Second)
+	cache.Set("key3", []byte("value3"), 5*time.Second)
+
+	// Add large entry that should trigger eviction
+	largeValue := make([]byte, 200)
+	cache.Set("large", largeValue, 5*time.Second)
+
+	// Memory should be under limit
+	suite.LessOrEqual(cache.GetMemoryUsage(), int64(500))
+}
+
+func (suite *LRUMemoryCacheTestSuite) TestCompression() {
+	cache := NewLRUMemoryCache(1024*1024, 100)
+
+	// Create a compressible value (> 1KB to trigger compression)
+	largeValue := make([]byte, 2048)
+	for i := range largeValue {
+		largeValue[i] = 'A' // Highly compressible
+	}
+
+	cache.Set("compressed", largeValue, 5*time.Second)
+
+	// Should be able to retrieve it correctly
+	val, found := cache.Get("compressed")
+	suite.True(found)
+	suite.Equal(largeValue, val)
+}
+
+func (suite *LRUMemoryCacheTestSuite) TestGetStats() {
+	cache := NewLRUMemoryCache(1024*1024, 100)
+
+	cache.Set("key1", []byte("value1"), 5*time.Second)
+	cache.Set("key2", []byte("value2"), 5*time.Second)
+
+	stats := cache.GetStats()
+	suite.Equal(int64(2), stats["entries"])
+	suite.Equal(int64(1024*1024), stats["max_memory"])
+	suite.Equal(int64(100), stats["max_entries"])
+	suite.NotNil(stats["memory_bytes"])
+	suite.NotNil(stats["fill_percent"])
+}
+
+func (suite *LRUMemoryCacheTestSuite) TestConcurrentAccess() {
+	cache := NewLRUMemoryCache(10*1024*1024, 1000)
+	const numGoroutines = 50
+	const numOperations = 500
+
+	var wg sync.WaitGroup
+	wg.Add(numGoroutines * 3) // readers, writers, deleters
+
+	// Writers
+	for i := 0; i < numGoroutines; i++ {
+		go func(id int) {
+			defer wg.Done()
+			for j := 0; j < numOperations; j++ {
+				key := fmt.Sprintf("key-%d-%d", id, j)
+				value := []byte(fmt.Sprintf("value-%d-%d", id, j))
+				cache.Set(key, value, 5*time.Second)
+			}
+		}(i)
+	}
+
+	// Readers
+	for i := 0; i < numGoroutines; i++ {
+		go func(id int) {
+			defer wg.Done()
+			for j := 0; j < numOperations; j++ {
+				key := fmt.Sprintf("key-%d-%d", id, j)
+				cache.Get(key)
+			}
+		}(i)
+	}
+
+	// Deleters
+	for i := 0; i < numGoroutines; i++ {
+		go func(id int) {
+			defer wg.Done()
+			for j := 0; j < numOperations; j++ {
+				key := fmt.Sprintf("key-%d-%d", id, j%100)
+				cache.Delete(key)
+			}
+		}(i)
+	}
+
+	wg.Wait()
+}
+
+func (suite *LRUMemoryCacheTestSuite) TestCleanExpiredEntries() {
+	cache := NewLRUMemoryCache(1024*1024, 100)
+
+	cache.Set("expire1", []byte("value1"), 50*time.Millisecond)
+	cache.Set("expire2", []byte("value2"), 50*time.Millisecond)
+	cache.Set("keep", []byte("value3"), 5*time.Second)
+
+	suite.Equal(int64(3), cache.CountQueries())
+
+	// Wait for some to expire
+	time.Sleep(100 * time.Millisecond)
+
+	// Clean expired entries
+	cache.CleanExpiredEntries()
+
+	// Only "keep" should remain
+	suite.Equal(int64(1), cache.CountQueries())
+
+	_, found := cache.Get("keep")
+	suite.True(found)
+}
+
+func (suite *LRUMemoryCacheTestSuite) TestCountQueries() {
+	cache := NewLRUMemoryCache(1024*1024, 100)
+
+	suite.Equal(int64(0), cache.CountQueries())
+
+	cache.Set("key1", []byte("value1"), 5*time.Second)
+	suite.Equal(int64(1), cache.CountQueries())
+
+	cache.Set("key2", []byte("value2"), 5*time.Second)
+	suite.Equal(int64(2), cache.CountQueries())
+
+	cache.Delete("key1")
+	suite.Equal(int64(1), cache.CountQueries())
+
+	cache.Clear()
+	suite.Equal(int64(0), cache.CountQueries())
+}
+
+// Benchmarks
+
+func BenchmarkLRUMemoryCacheSet(b *testing.B) {
+	cache := NewLRUMemoryCache(100*1024*1024, 100000)
+	value := []byte("benchmark-value")
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		key := fmt.Sprintf("key-%d", i)
+		cache.Set(key, value, 5*time.Second)
+	}
+}
+
+func BenchmarkLRUMemoryCacheGet(b *testing.B) {
+	cache := NewLRUMemoryCache(100*1024*1024, 100000)
+	value := []byte("benchmark-value")
+
+	// Pre-populate
+	for i := 0; i < 10000; i++ {
+		key := fmt.Sprintf("key-%d", i)
+		cache.Set(key, value, 5*time.Minute)
+	}
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		key := fmt.Sprintf("key-%d", i%10000)
+		cache.Get(key)
+	}
+}
+
+func BenchmarkLRUMemoryCacheConcurrent(b *testing.B) {
+	cache := NewLRUMemoryCache(100*1024*1024, 100000)
+	value := []byte("benchmark-value")
+
+	b.RunParallel(func(pb *testing.PB) {
+		i := 0
+		for pb.Next() {
+			key := fmt.Sprintf("key-%d", i)
+			if i%2 == 0 {
+				cache.Set(key, value, 5*time.Second)
+			} else {
+				cache.Get(key)
+			}
+			i++
+		}
+	})
+}