feat: apply cache to tag

backend/cmd/server/main.go

@@ -14,6 +14,7 @@ import (
 	"time"
 
 	"github.com/Sosokker/todolist-backend/internal/api"
+	"github.com/Sosokker/todolist-backend/internal/cache"
 	"github.com/Sosokker/todolist-backend/internal/config"
 	"github.com/Sosokker/todolist-backend/internal/repository"
 	"github.com/Sosokker/todolist-backend/internal/service"
@@ -53,7 +54,10 @@ func main() {
 		os.Exit(1)
 	}
 
-	repoRegistry := repository.NewRepositoryRegistry(pool)
+	// --- Cache Setup ---
+	appCache := cache.NewMemoryCache(cfg.Cache, logger)
+
+	repoRegistry := repository.NewRepositoryRegistry(pool, appCache, logger)
 
 	var storageService service.FileStorageService
 	storageService, err = service.NewGCStorageService(cfg.Storage.GCS, logger)

backend/internal/cache/cache.go

@@ -20,17 +20,28 @@ type Cache interface {
 type memoryCache struct {
 	client            *gocache.Cache
 	logger            *slog.Logger
+	defaultExpiration time.Duration
 }
 
 // NewMemoryCache creates a new in-memory cache
 func NewMemoryCache(cfg config.CacheConfig, logger *slog.Logger) Cache {
-	c := gocache.New(cfg.DefaultExpiration, cfg.CleanupInterval)
+	defaultExp := cfg.DefaultExpiration
+	if defaultExp <= 0 {
+		defaultExp = 5 * time.Minute
+	}
+	cleanupInterval := cfg.CleanupInterval
+	if cleanupInterval <= 0 {
+		cleanupInterval = 10 * time.Minute
+	}
+
+	c := gocache.New(defaultExp, cleanupInterval)
 	logger.Info("In-memory cache initialized",
-		"defaultExpiration", cfg.DefaultExpiration,
-		"cleanupInterval", cfg.CleanupInterval)
+		"defaultExpiration", defaultExp,
+		"cleanupInterval", cleanupInterval)
 	return &memoryCache{
 		client:            c,
-		logger: logger,
+		logger:            logger.With("component", "memoryCache"),
+		defaultExpiration: defaultExp,
 	}
 }
 
@@ -45,8 +56,12 @@ func (m *memoryCache) Get(ctx context.Context, key string) (interface{}, bool) {
 }
 
 func (m *memoryCache) Set(ctx context.Context, key string, value interface{}, duration time.Duration) {
-	m.logger.DebugContext(ctx, "Setting cache", "key", key, "duration", duration)
-	m.client.Set(key, value, duration) // duration=0 means use default, -1 means never expire (DefaultExpiration)
+	exp := duration
+	if exp <= 0 {
+		exp = m.defaultExpiration
+	}
+	m.logger.DebugContext(ctx, "Setting cache", "key", key, "duration", exp)
+	m.client.Set(key, value, exp)
 }
 
 func (m *memoryCache) Delete(ctx context.Context, key string) {

backend/internal/repository/interfaces.go

@@ -2,8 +2,10 @@ package repository
 
 import (
 	"context"
+	"log/slog"
 	"time"
 
+	"github.com/Sosokker/todolist-backend/internal/cache"
 	"github.com/Sosokker/todolist-backend/internal/domain"
 	db "github.com/Sosokker/todolist-backend/internal/repository/sqlc/generated"
 	"github.com/google/uuid"
@@ -82,14 +84,22 @@ type RepositoryRegistry struct {
 	Pool *pgxpool.Pool
 }
 
-// NewRepositoryRegistry creates a new registry
-func NewRepositoryRegistry(pool *pgxpool.Pool) *RepositoryRegistry {
+// NewRepositoryRegistry creates a new registry, now with caching decorators
+func NewRepositoryRegistry(pool *pgxpool.Pool, cache cache.Cache, logger *slog.Logger) *RepositoryRegistry {
 	queries := db.New(pool)
+
+	pgxUserRepo := NewPgxUserRepository(queries)
+	pgxTagRepo := NewPgxTagRepository(queries)
+	pgxTodoRepo := NewPgxTodoRepository(queries, pool)
+	pgxSubtaskRepo := NewPgxSubtaskRepository(queries)
+
+	cachingTagRepo := NewCachingTagRepository(pgxTagRepo, cache, logger)
+
 	return &RepositoryRegistry{
-		UserRepo:    NewPgxUserRepository(queries),
-		TagRepo:     NewPgxTagRepository(queries),
-		TodoRepo:    NewPgxTodoRepository(queries, pool),
-		SubtaskRepo: NewPgxSubtaskRepository(queries),
+		UserRepo:    pgxUserRepo,    // Not cached yet in this example
+		TagRepo:     cachingTagRepo, // Use the caching decorator
+		TodoRepo:    pgxTodoRepo,    // Not cached yet in this example
+		SubtaskRepo: pgxSubtaskRepo, // Not cached yet in this example
 		Queries:     queries,
 		Pool:        pool,
 	}

backend/internal/repository/tag_repo_cache.go

@@ -0,0 +1,95 @@
+package repository
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+
+	"github.com/Sosokker/todolist-backend/internal/cache"
+	"github.com/Sosokker/todolist-backend/internal/domain"
+	"github.com/google/uuid"
+)
+
+type cachingTagRepository struct {
+	next   TagRepository
+	cache  cache.Cache
+	logger *slog.Logger
+}
+
+func NewCachingTagRepository(next TagRepository, cache cache.Cache, logger *slog.Logger) TagRepository {
+	return &cachingTagRepository{
+		next:   next,
+		cache:  cache,
+		logger: logger.With("repository", "tag_cache_decorator"),
+	}
+}
+
+// --- Cache Key Generation ---
+func tagCacheKey(userID, tagID uuid.UUID) string {
+	return fmt.Sprintf("user:%s:tag:%s", userID, tagID)
+}
+
+// --- TagRepository Interface Implementation ---
+
+func (r *cachingTagRepository) Create(ctx context.Context, tag *domain.Tag) (*domain.Tag, error) {
+	createdTag, err := r.next.Create(ctx, tag)
+	// Invalidate list caches if/when implemented
+	return createdTag, err
+}
+
+func (r *cachingTagRepository) GetByID(ctx context.Context, id, userID uuid.UUID) (*domain.Tag, error) {
+	cacheKey := tagCacheKey(userID, id)
+	if cached, found := r.cache.Get(ctx, cacheKey); found {
+		if tag, ok := cached.(*domain.Tag); ok {
+			r.logger.DebugContext(ctx, "GetTagByID cache hit", "key", cacheKey)
+			return tag, nil
+		}
+		// Invalid type in cache, treat as miss and delete
+		r.logger.WarnContext(ctx, "Invalid type found in tag cache", "key", cacheKey, "type", fmt.Sprintf("%T", cached))
+		r.cache.Delete(ctx, cacheKey)
+	}
+
+	r.logger.DebugContext(ctx, "GetTagByID cache miss", "key", cacheKey)
+	tag, err := r.next.GetByID(ctx, id, userID)
+	if err != nil {
+		return nil, err
+	}
+
+	if tag != nil {
+		r.cache.Set(ctx, cacheKey, tag, 0)
+		r.logger.DebugContext(ctx, "Set tag in cache", "key", cacheKey)
+	}
+
+	return tag, nil
+}
+
+func (r *cachingTagRepository) Update(ctx context.Context, id, userID uuid.UUID, updateData *domain.Tag) (*domain.Tag, error) {
+	updatedTag, err := r.next.Update(ctx, id, userID, updateData)
+	if err != nil {
+		return nil, err
+	}
+	cacheKey := tagCacheKey(userID, id)
+	r.cache.Delete(ctx, cacheKey)
+	r.logger.DebugContext(ctx, "Invalidated tag cache after update", "key", cacheKey)
+	return updatedTag, nil
+}
+
+func (r *cachingTagRepository) Delete(ctx context.Context, id, userID uuid.UUID) error {
+	err := r.next.Delete(ctx, id, userID)
+	if err != nil {
+		return err
+	}
+	cacheKey := tagCacheKey(userID, id)
+	r.cache.Delete(ctx, cacheKey)
+	r.logger.DebugContext(ctx, "Invalidated tag cache after delete", "key", cacheKey)
+	return nil
+}
+
+// --- Pass-through methods ---
+func (r *cachingTagRepository) GetByIDs(ctx context.Context, ids []uuid.UUID, userID uuid.UUID) ([]domain.Tag, error) {
+	return r.next.GetByIDs(ctx, ids, userID)
+}
+
+func (r *cachingTagRepository) ListByUser(ctx context.Context, userID uuid.UUID) ([]domain.Tag, error) {
+	return r.next.ListByUser(ctx, userID)
+}