Manager: wrap Worker fetching errors

Do the same wrapping as for task/job errors, but then for workers.

internal/manager/persistence/errors.go

@@ -11,6 +11,7 @@ import (
 var (
 	ErrJobNotFound    = PersistenceError{Message: "job not found", Err: gorm.ErrRecordNotFound}
 	ErrTaskNotFound   = PersistenceError{Message: "task not found", Err: gorm.ErrRecordNotFound}
+	ErrWorkerNotFound = PersistenceError{Message: "worker not found", Err: gorm.ErrRecordNotFound}
 )
 
 type PersistenceError struct {
@@ -34,6 +35,10 @@ func taskError(errorToWrap error, message string, msgArgs ...interface{}) error
 	return wrapError(translateGormTaskError(errorToWrap), message, msgArgs...)
 }
 
+func workerError(errorToWrap error, message string, msgArgs ...interface{}) error {
+	return wrapError(translateGormWorkerError(errorToWrap), message, msgArgs...)
+}
+
 func wrapError(errorToWrap error, message string, format ...interface{}) error {
 	// Only format if there are arguments for formatting.
 	var formattedMsg string
@@ -66,3 +71,12 @@ func translateGormTaskError(gormError error) error {
 	}
 	return gormError
 }
+
+// translateGormWorkerError translates a Gorm error to a persistence layer error.
+// This helps to keep Gorm as "implementation detail" of the persistence layer.
+func translateGormWorkerError(gormError error) error {
+	if errors.Is(gormError, gorm.ErrRecordNotFound) {
+		return ErrWorkerNotFound
+	}
+	return gormError
+}

internal/manager/persistence/workers.go

@@ -44,7 +44,7 @@ func (db *DB) FetchWorker(ctx context.Context, uuid string) (*Worker, error) {
 	tx := db.gormDB.WithContext(ctx).
 		First(&w, "uuid = ?", uuid)
 	if tx.Error != nil {
-		return nil, tx.Error
+		return nil, workerError(tx.Error, "fetching worker")
 	}
 	return &w, nil
 }
@@ -53,7 +53,7 @@ func (db *DB) FetchWorkers(ctx context.Context) ([]*Worker, error) {
 	workers := make([]*Worker, 0)
 	tx := db.gormDB.WithContext(ctx).Model(&Worker{}).Scan(&workers)
 	if tx.Error != nil {
-		return nil, tx.Error
+		return nil, workerError(tx.Error, "fetching all workers")
 	}
 	return workers, nil
 }

internal/manager/persistence/workers_test.go

@@ -17,6 +17,12 @@ func TestCreateFetchWorker(t *testing.T) {
 	ctx, cancel, db := persistenceTestFixtures(t, 1*time.Second)
 	defer cancel()
 
+	// Test fetching non-existent worker
+	fetchedWorker, err := db.FetchWorker(ctx, "dabf67a1-b591-4232-bf73-0b8de2a9488e")
+	assert.ErrorIs(t, err, ErrWorkerNotFound)
+	assert.Nil(t, fetchedWorker)
+
+	// Test existing worker
 	w := Worker{
 		UUID:               uuid.New(),
 		Name:               "дрон",
@@ -27,10 +33,10 @@ func TestCreateFetchWorker(t *testing.T) {
 		SupportedTaskTypes: "blender,ffmpeg,file-management",
 	}
 
-	err := db.CreateWorker(ctx, &w)
+	err = db.CreateWorker(ctx, &w)
 	assert.NoError(t, err)
 
-	fetchedWorker, err := db.FetchWorker(ctx, w.UUID)
+	fetchedWorker, err = db.FetchWorker(ctx, w.UUID)
 	assert.NoError(t, err)
 	assert.NotNil(t, fetchedWorker)