fix: connect to previous database on error

drivers/postgres.go

@@ -13,12 +13,17 @@ import (
 )
 
 type Postgres struct {
-	Connection      *sql.DB
-	Provider        string
-	CurrentDatabase string
-	Urlstr          string
+	Connection       *sql.DB
+	Provider         string
+	CurrentDatabase  string
+	PreviousDatabase string
+	Urlstr           string
 }
 
+const (
+	DEFAULT_PORT = "5432"
+)
+
 func (db *Postgres) Connect(urlstr string) (err error) {
 	db.SetProvider("postgres")
 
@@ -38,7 +43,12 @@ func (db *Postgres) Connect(urlstr string) (err error) {
 
 	rows := db.Connection.QueryRow("SELECT current_database();")
 
-	err = rows.Scan(&db.CurrentDatabase)
+	database := ""
+
+	err = rows.Scan(&database)
+
+	db.CurrentDatabase = database
+	db.PreviousDatabase = database
 	if err != nil {
 		return err
 	}
@@ -71,38 +81,24 @@ func (db *Postgres) GetDatabases() (databases []string, err error) {
 func (db *Postgres) GetTables(database string) (tables map[string][]string, err error) {
 	tables = make(map[string][]string)
 
-	if database != db.CurrentDatabase {
-		parsedConn, err := dburl.Parse(db.Urlstr)
-		if err != nil {
-			return tables, err
-		}
-
-		user := parsedConn.User.Username()
-		password, _ := parsedConn.User.Password()
-		host := parsedConn.Host
-		port := parsedConn.Port()
-		dbname := parsedConn.Path
+	switchDatabase := false
 
-		if port == "" {
-			port = "5432"
-		}
-
-		if dbname == "" {
-			dbname = database
-		}
-
-		db.Connection.Close()
-
-		db.Connection, err = sql.Open("postgres", fmt.Sprintf("host=%s port=%s user=%s password=%s dbname='%s' sslmode=disable", host, port, user, password, dbname))
+	if database != db.CurrentDatabase {
+		err = db.SwitchDatabase(database)
 		if err != nil {
 			return tables, err
 		}
-
-		db.CurrentDatabase = database
+		switchDatabase = true
 	}
 
 	rows, err := db.Connection.Query(fmt.Sprintf("SELECT table_name, table_schema FROM information_schema.tables WHERE table_catalog = '%s'", database))
 	if err != nil {
+		if switchDatabase {
+			err = db.SwitchDatabase(db.PreviousDatabase)
+			if err != nil {
+				return tables, err
+			}
+		}
 		return tables, err
 	}
 
@@ -542,3 +538,36 @@ func (db *Postgres) SetProvider(provider string) {
 func (db *Postgres) GetProvider() string {
 	return db.Provider
 }
+
+func (db *Postgres) SwitchDatabase(database string) error {
+	parsedConn, err := dburl.Parse(db.Urlstr)
+	if err != nil {
+		return err
+	}
+
+	user := parsedConn.User.Username()
+	password, _ := parsedConn.User.Password()
+	host := parsedConn.Host
+	port := parsedConn.Port()
+	dbname := parsedConn.Path
+
+	if port == "" {
+		port = DEFAULT_PORT
+	}
+
+	if dbname == "" {
+		dbname = database
+	}
+
+	connection, err := sql.Open("postgres", fmt.Sprintf("host=%s port=%s user=%s password=%s dbname='%s' sslmode=disable", host, port, user, password, dbname))
+	if err != nil {
+		return err
+	}
+
+	db.Connection.Close()
+	db.Connection = connection
+	db.PreviousDatabase = db.CurrentDatabase
+	db.CurrentDatabase = database
+
+	return nil
+}