Add ErrExecutingRollback error

Author: C

postgresql/error.go

@@ -23,4 +23,7 @@ var (
 	// ErrScanningRows is returned when the worker fails to scan the rows
 	// returned by a query.
 	ErrScanningRows = errors.New("error trying to scan result rows")
+	// ErrExecutingRollback is returned when the worker fails to rollback
+	// in a transaction.
+	ErrExecutingRollback = errors.New("error trying to rollback a transaction in database")
 )

postgresql/stats.go

@@ -6,40 +6,56 @@ import (
 	"github.com/benchttp/worker/stats"
 )
 
-func (s StatsService) Create(stats stats.Stats, statsId, userId, tag string) error {
+// nolint:gocognit
+func (s StatsService) Create(statsToStore stats.Stats, statsID, userId, tag string) error {
 	tx, err := s.db.Begin()
 	if err != nil {
 		return err
 	}
 
 	insertIntoStatsDescriptor, err := tx.Prepare(`INSERT INTO public.stats_descriptor(id, user_id, tag, finished_at) VALUES($1, $2, $3, '2022-03-03 17:36:38-02')`)
 	if err != nil {
-		tx.Rollback()
+		err = tx.Rollback()
+		if err != nil {
+			return ErrExecutingRollback
+		}
 		return ErrPreparingStmt
 	}
 	defer insertIntoStatsDescriptor.Close()
 
-	if _, err = insertIntoStatsDescriptor.Exec(statsId, userId, tag); err != nil {
-		tx.Rollback()
+	if _, err = insertIntoStatsDescriptor.Exec(statsID, userId, tag); err != nil {
+		err = tx.Rollback()
+		if err != nil {
+			return ErrExecutingRollback
+		}
 		return ErrExecutingPreparedStmt
 	}
 
 	insertIntoTimestats, err := tx.Prepare(`INSERT INTO public.timestats(stats_descriptor_id, min, max, mean, median, standard_deviation, deciles) VALUES
 	($1, $2, $3, $4, $5, $6, $7)`)
 	if err != nil {
-		tx.Rollback()
+		err = tx.Rollback()
+		if err != nil {
+			return ErrExecutingRollback
+		}
 		return ErrPreparingStmt
 	}
 	defer insertIntoTimestats.Close()
 
-	if _, err = insertIntoTimestats.Exec(statsId, stats.Min, stats.Max, stats.Mean, stats.Median, stats.StdDev, pq.Array(stats.Deciles)); err != nil {
-		tx.Rollback()
+	if _, err = insertIntoTimestats.Exec(statsID, statsToStore.Min, statsToStore.Max, statsToStore.Mean, statsToStore.Median, statsToStore.StdDev, pq.Array(statsToStore.Deciles)); err != nil {
+		err = tx.Rollback()
+		if err != nil {
+			return ErrExecutingRollback
+		}
 		return ErrExecutingPreparedStmt
 	}
 
 	err = tx.Commit()
 	if err != nil {
-		tx.Rollback()
+		err = tx.Rollback()
+		if err != nil {
+			return ErrExecutingRollback
+		}
 		return err
 	}
 	return nil