Added cache, funcspec and implemented total cache

pkg/cache/provider_memcache.go

@@ -0,0 +1,144 @@
+package cache
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/bradfitz/gomemcache/memcache"
+)
+
+// MemcacheProvider is a Memcache implementation of the Provider interface.
+type MemcacheProvider struct {
+	client  *memcache.Client
+	options *Options
+}
+
+// MemcacheConfig contains Memcache-specific configuration.
+type MemcacheConfig struct {
+	// Servers is a list of memcache server addresses (e.g., "localhost:11211")
+	Servers []string
+
+	// MaxIdleConns is the maximum number of idle connections (default: 2)
+	MaxIdleConns int
+
+	// Timeout for connection operations (default: 1 second)
+	Timeout time.Duration
+
+	// Options contains general cache options
+	Options *Options
+}
+
+// NewMemcacheProvider creates a new Memcache cache provider.
+func NewMemcacheProvider(config *MemcacheConfig) (*MemcacheProvider, error) {
+	if config == nil {
+		config = &MemcacheConfig{
+			Servers: []string{"localhost:11211"},
+		}
+	}
+
+	if len(config.Servers) == 0 {
+		config.Servers = []string{"localhost:11211"}
+	}
+
+	if config.MaxIdleConns == 0 {
+		config.MaxIdleConns = 2
+	}
+
+	if config.Timeout == 0 {
+		config.Timeout = 1 * time.Second
+	}
+
+	if config.Options == nil {
+		config.Options = &Options{
+			DefaultTTL: 5 * time.Minute,
+		}
+	}
+
+	client := memcache.New(config.Servers...)
+	client.MaxIdleConns = config.MaxIdleConns
+	client.Timeout = config.Timeout
+
+	// Test connection
+	if err := client.Ping(); err != nil {
+		return nil, fmt.Errorf("failed to connect to Memcache: %w", err)
+	}
+
+	return &MemcacheProvider{
+		client:  client,
+		options: config.Options,
+	}, nil
+}
+
+// Get retrieves a value from the cache by key.
+func (m *MemcacheProvider) Get(ctx context.Context, key string) ([]byte, bool) {
+	item, err := m.client.Get(key)
+	if err == memcache.ErrCacheMiss {
+		return nil, false
+	}
+	if err != nil {
+		return nil, false
+	}
+	return item.Value, true
+}
+
+// Set stores a value in the cache with the specified TTL.
+func (m *MemcacheProvider) Set(ctx context.Context, key string, value []byte, ttl time.Duration) error {
+	if ttl == 0 {
+		ttl = m.options.DefaultTTL
+	}
+
+	item := &memcache.Item{
+		Key:        key,
+		Value:      value,
+		Expiration: int32(ttl.Seconds()),
+	}
+
+	return m.client.Set(item)
+}
+
+// Delete removes a key from the cache.
+func (m *MemcacheProvider) Delete(ctx context.Context, key string) error {
+	err := m.client.Delete(key)
+	if err == memcache.ErrCacheMiss {
+		return nil
+	}
+	return err
+}
+
+// DeleteByPattern removes all keys matching the pattern.
+// Note: Memcache does not support pattern-based deletion natively.
+// This is a no-op for memcache and returns an error.
+func (m *MemcacheProvider) DeleteByPattern(ctx context.Context, pattern string) error {
+	return fmt.Errorf("pattern-based deletion is not supported by Memcache")
+}
+
+// Clear removes all items from the cache.
+func (m *MemcacheProvider) Clear(ctx context.Context) error {
+	return m.client.FlushAll()
+}
+
+// Exists checks if a key exists in the cache.
+func (m *MemcacheProvider) Exists(ctx context.Context, key string) bool {
+	_, err := m.client.Get(key)
+	return err == nil
+}
+
+// Close closes the provider and releases any resources.
+func (m *MemcacheProvider) Close() error {
+	// Memcache client doesn't have a close method
+	return nil
+}
+
+// Stats returns statistics about the cache provider.
+// Note: Memcache provider returns limited statistics.
+func (m *MemcacheProvider) Stats(ctx context.Context) (*CacheStats, error) {
+	stats := &CacheStats{
+		ProviderType: "memcache",
+		ProviderStats: map[string]any{
+			"note": "Memcache does not provide detailed statistics through the standard client",
+		},
+	}
+
+	return stats, nil
+}