Added cache, funcspec and implemented total cache

pkg/cache/provider.go

@@ -0,0 +1,57 @@
+package cache
+
+import (
+	"context"
+	"time"
+)
+
+// Provider defines the interface that all cache providers must implement.
+type Provider interface {
+	// Get retrieves a value from the cache by key.
+	// Returns nil, false if key doesn't exist or is expired.
+	Get(ctx context.Context, key string) ([]byte, bool)
+
+	// Set stores a value in the cache with the specified TTL.
+	// If ttl is 0, the item never expires.
+	Set(ctx context.Context, key string, value []byte, ttl time.Duration) error
+
+	// Delete removes a key from the cache.
+	Delete(ctx context.Context, key string) error
+
+	// DeleteByPattern removes all keys matching the pattern.
+	// Pattern syntax depends on the provider implementation.
+	DeleteByPattern(ctx context.Context, pattern string) error
+
+	// Clear removes all items from the cache.
+	Clear(ctx context.Context) error
+
+	// Exists checks if a key exists in the cache.
+	Exists(ctx context.Context, key string) bool
+
+	// Close closes the provider and releases any resources.
+	Close() error
+
+	// Stats returns statistics about the cache provider.
+	Stats(ctx context.Context) (*CacheStats, error)
+}
+
+// CacheStats contains cache statistics.
+type CacheStats struct {
+	Hits          int64                  `json:"hits"`
+	Misses        int64                  `json:"misses"`
+	Keys          int64                  `json:"keys"`
+	ProviderType  string                 `json:"provider_type"`
+	ProviderStats map[string]any `json:"provider_stats,omitempty"`
+}
+
+// Options contains configuration options for cache providers.
+type Options struct {
+	// DefaultTTL is the default time-to-live for cache items.
+	DefaultTTL time.Duration
+
+	// MaxSize is the maximum number of items (for in-memory provider).
+	MaxSize int
+
+	// EvictionPolicy determines how items are evicted (LRU, LFU, etc).
+	EvictionPolicy string
+}