Remotecache: Avoid race condition in Set causing error on insert. (#17082)

* remotecache: avoid race condition in set

since set called the database twice without transactions another
operation could insert a value before the first operation completed.
which would raise an error on insert since the data have been inserted
by the other request.

closes #17079

pkg/infra/remotecache/database_storage.go

@@ -39,10 +39,14 @@ func (dc *databaseCache) Run(ctx context.Context) error {
 }
 
 func (dc *databaseCache) internalRunGC() {
+	err := dc.SQLStore.WithDbSession(context.Background(), func(session *sqlstore.DBSession) error {
 		now := getTime().Unix()
 		sql := `DELETE FROM cache_data WHERE (? - created_at) >= expires AND expires <> 0`
 
-	_, err := dc.SQLStore.NewSession().Exec(sql, now)
+		_, err := session.Exec(sql, now)
+		return err
+	})
+
 	if err != nil {
 		dc.log.Error("failed to run garbage collect", "error", err)
 	}
@@ -80,14 +84,13 @@ func (dc *databaseCache) Get(key string) (interface{}, error) {
 }
 
 func (dc *databaseCache) Set(key string, value interface{}, expire time.Duration) error {
+	return dc.SQLStore.WithTransactionalDbSession(context.Background(), func(session *sqlstore.DBSession) error {
 		item := &cachedItem{Val: value}
 		data, err := encodeGob(item)
 		if err != nil {
 			return err
 		}
 
-	session := dc.SQLStore.NewSession()
-
 		var cacheHit CacheData
 		has, err := session.Where("cache_key = ?", key).Get(&cacheHit)
 		if err != nil {
@@ -109,15 +112,20 @@ func (dc *databaseCache) Set(key string, value interface{}, expire time.Duration
 		}
 
 		return err
+	})
 }
 
 func (dc *databaseCache) Delete(key string) error {
+	return dc.SQLStore.WithDbSession(context.Background(), func(session *sqlstore.DBSession) error {
 		sql := "DELETE FROM cache_data WHERE cache_key=?"
-	_, err := dc.SQLStore.NewSession().Exec(sql, key)
+		_, err := session.Exec(sql, key)
 
 		return err
+	})
+
 }
 
+// CacheData is the struct representing the table in the database
 type CacheData struct {
 	CacheKey  string
 	Data      []byte