Method readRowByKeyWithTransaction

lib/gcpspanner/client.go:825–852

readRowByKey retrieves the row of an entity based on its external key with transaction.

(
	ctx context.Context,
	key Key,
	txn transaction,
)

// readRowByKey retrieves the row of an entity based on its external key with transaction.
func (c *entityReader[M, ExternalStruct, SpannerStruct, Key]) readRowByKeyWithTransaction(
	ctx context.Context,
	key Key,
	txn transaction,
) (*SpannerStruct, error) {
	var mapper M
	stmt := mapper.SelectOne(key)
	// Attempt to query for the row.
	it := txn.Query(ctx, stmt)
	defer it.Stop()
	row, err := it.Next()
	if err != nil {
		// No row found
		if errors.Is(err, iterator.Done) {
			return nil, errors.Join(ErrQueryReturnedNoResults, err)
		}

		// Catch-all for other errors.
		return nil, errors.Join(ErrInternalQueryFailure, err)
	}
	existing := new(SpannerStruct)
	err = row.ToStruct(existing)
	if err != nil {
		return nil, errors.Join(ErrInternalQueryFailure, err)
	}

	return existing, nil
}

func (c *entityWriterWithIDRetrieval[M, ExternalStruct, SpannerStruct, Key, ID]) getIDByKey(
	ctx context.Context,