Fix critical resilience issues from code review

- DB connection pool: Allow 5 connections instead of 1 for better concurrency
- JSON unmarshal: Add error handling to prevent nil slice issues
- Context cancellation: Check ctx.Done() in aggregateData goroutines
- Migration path: Make configurable via MIGRATION_DIR env var

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

6 files changed, 46 insertions, 11 deletions

diff --git a/internal/config/config.go b/internal/config/config.go
index ba2719d..62e733a 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -20,6 +20,7 @@ type Config struct {
 
 	// Paths
 	DatabasePath string
+	MigrationDir string
 	TemplateDir  string
 	StaticDir    string
 
@@ -44,6 +45,7 @@ func Load() (*Config, error) {
 
 		// Paths
 		DatabasePath: getEnvWithDefault("DATABASE_PATH", "./dashboard.db"),
+		MigrationDir: getEnvWithDefault("MIGRATION_DIR", "migrations"),
 		TemplateDir:  getEnvWithDefault("TEMPLATE_DIR", "web/templates"),
 		StaticDir:    getEnvWithDefault("STATIC_DIR", "web/static"),
 
diff --git a/internal/handlers/handlers.go b/internal/handlers/handlers.go
index c44e771..b8fc574 100644
--- a/internal/handlers/handlers.go
+++ b/internal/handlers/handlers.go
@@ -207,6 +207,11 @@ func (h *Handler) aggregateData(ctx context.Context, forceRefresh bool) (*models
 	wg.Add(1)
 	go func() {
 		defer wg.Done()
+		select {
+		case <-ctx.Done():
+			return
+		default:
+		}
 		boards, err := h.fetchBoards(ctx, forceRefresh)
 		mu.Lock()
 		defer mu.Unlock()
@@ -221,6 +226,11 @@ func (h *Handler) aggregateData(ctx context.Context, forceRefresh bool) (*models
 	wg.Add(1)
 	go func() {
 		defer wg.Done()
+		select {
+		case <-ctx.Done():
+			return
+		default:
+		}
 		tasks, err := h.fetchTasks(ctx, forceRefresh)
 		mu.Lock()
 		defer mu.Unlock()
@@ -255,6 +265,11 @@ func (h *Handler) aggregateData(ctx context.Context, forceRefresh bool) (*models
 	wg.Add(1)
 	go func() {
 		defer wg.Done()
+		select {
+		case <-ctx.Done():
+			return
+		default:
+		}
 		projects, err := h.todoistClient.GetProjects(ctx)
 		mu.Lock()
 		defer mu.Unlock()
@@ -270,6 +285,11 @@ func (h *Handler) aggregateData(ctx context.Context, forceRefresh bool) (*models
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
+			select {
+			case <-ctx.Done():
+				return
+			default:
+			}
 			meals, err := h.fetchMeals(ctx, forceRefresh)
 			mu.Lock()
 			defer mu.Unlock()
@@ -286,6 +306,11 @@ func (h *Handler) aggregateData(ctx context.Context, forceRefresh bool) (*models
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
+			select {
+			case <-ctx.Done():
+				return
+			default:
+			}
 			events, err := h.googleCalendarClient.GetUpcomingEvents(ctx, 10)
 			mu.Lock()
 			defer mu.Unlock()
diff --git a/internal/handlers/handlers_test.go b/internal/handlers/handlers_test.go
index e4a9f05..5628237 100644
--- a/internal/handlers/handlers_test.go
+++ b/internal/handlers/handlers_test.go
@@ -39,7 +39,7 @@ func setupTestDB(t *testing.T) (*store.Store, func()) {
 	}
 
 	// Initialize store (this runs migrations)
-	db, err := store.New(tmpFile.Name())
+	db, err := store.New(tmpFile.Name(), "migrations")
 	if err != nil {
 		os.Chdir(originalDir)
 		os.Remove(tmpFile.Name())
diff --git a/internal/handlers/heuristic_test.go b/internal/handlers/heuristic_test.go
index 2b70218..b03b664 100644
--- a/internal/handlers/heuristic_test.go
+++ b/internal/handlers/heuristic_test.go
@@ -33,7 +33,7 @@ func TestHandleTasks_Heuristic(t *testing.T) {
 	defer os.Chdir(originalDir)
 
 	// Initialize store (this runs migrations)
-	db, err := store.New(tmpFile.Name())
+	db, err := store.New(tmpFile.Name(), "migrations")
 	if err != nil {
 		t.Fatalf("Failed to initialize store: %v", err)
 	}
diff --git a/internal/handlers/tab_state_test.go b/internal/handlers/tab_state_test.go
index d7bb8dd..60f1340 100644
--- a/internal/handlers/tab_state_test.go
+++ b/internal/handlers/tab_state_test.go
@@ -13,7 +13,7 @@ import (
 
 func TestHandleDashboard_TabState(t *testing.T) {
 	// Create a temporary database for testing
-	db, err := store.New(":memory:")
+	db, err := store.New(":memory:", "../../migrations")
 	if err != nil {
 		t.Fatalf("Failed to create test database: %v", err)
 	}
diff --git a/internal/store/sqlite.go b/internal/store/sqlite.go
index 069313a..a4d01a2 100644
--- a/internal/store/sqlite.go
+++ b/internal/store/sqlite.go
@@ -22,11 +22,12 @@ const (
 )
 
 type Store struct {
-	db *sql.DB
+	db           *sql.DB
+	migrationDir string
 }
 
 // New creates a new Store instance and runs migrations
-func New(dbPath string) (*Store, error) {
+func New(dbPath, migrationDir string) (*Store, error) {
 	db, err := sql.Open("sqlite3", dbPath)
 	if err != nil {
 		return nil, fmt.Errorf("failed to open database: %w", err)
@@ -42,10 +43,13 @@ func New(dbPath string) (*Store, error) {
 		return nil, fmt.Errorf("failed to enable WAL mode: %w", err)
 	}
 
-	// Serialize writes to prevent "database is locked" errors
-	db.SetMaxOpenConns(1)
+	// Configure connection pool for SQLite with WAL mode
+	// WAL allows concurrent reads, but writes still need serialization
+	db.SetMaxOpenConns(5)
+	db.SetMaxIdleConns(2)
+	db.SetConnMaxLifetime(time.Hour)
 
-	store := &Store{db: db}
+	store := &Store{db: db, migrationDir: migrationDir}
 
 	// Run migrations
 	if err := store.runMigrations(); err != nil {
@@ -67,8 +71,9 @@ func (s *Store) DB() *sql.DB {
 
 // runMigrations executes all migration files in order
 func (s *Store) runMigrations() error {
-	// Get migration files
-	migrationFiles, err := filepath.Glob("migrations/*.sql")
+	// Get migration files from configured directory
+	pattern := filepath.Join(s.migrationDir, "*.sql")
+	migrationFiles, err := filepath.Glob(pattern)
 	if err != nil {
 		return fmt.Errorf("failed to read migration files: %w", err)
 	}
@@ -178,7 +183,10 @@ func (s *Store) GetTasks() ([]models.Task, error) {
 			task.DueDate = &dueDate.Time
 		}
 
-		json.Unmarshal([]byte(labelsJSON), &task.Labels)
+		if err := json.Unmarshal([]byte(labelsJSON), &task.Labels); err != nil {
+			log.Printf("Warning: failed to unmarshal labels for task %s: %v", task.ID, err)
+			task.Labels = []string{}
+		}
 		tasks = append(tasks, task)
 	}