fix: Restore fails with bufio.Scanner: token too long when importing large dump files

Author: n2em

pkg/database/restore.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"io"
 	"regexp"
+	"strings"
 )
 
 const (
@@ -31,20 +32,33 @@ func Restore(ctx context.Context, dbconn *Connection, databasesMap map[string]st
 		if err != nil {
 			return fmt.Errorf("failed to restore database: %w", err)
 		}
-		scanBuf := []byte{}
-		scanner := bufio.NewScanner(r)
-		// increase the buffer size
-		scanner.Buffer(scanBuf, defaultMaxAllowedPacket) //TODO should be a configurable option like with dump
+		reader := bufio.NewReader(r)
 		var current string
-		for scanner.Scan() {
-			line := scanner.Text()
+		for {
+			line, err := reader.ReadString('\n')
+			if err != nil && err != io.EOF {
+				_ = tx.Rollback()
+				return fmt.Errorf("failed to restore database: %w", err)
+			}
+			// strip CRLF/newline
+			line = strings.TrimRight(line, "\r\n")
 			if line == "" {
+				if err == io.EOF {
+					break
+				}
 				continue
 			}
 			current += line + "\n"
+
+			// if the line does not end with a semicolon, keep accumulating
 			if line[len(line)-1] != ';' {
+				if err == io.EOF {
+					// EOF reached but statement not terminated; we'll try to execute below
+					break
+				}
 				continue
 			}
+
 			// if we have the line that sets the database, and we need to replace, replace it
 			if createRegex.MatchString(current) {
 				dbName := createRegex.FindStringSubmatch(current)[3]
@@ -64,9 +78,17 @@ func Restore(ctx context.Context, dbconn *Connection, databasesMap map[string]st
 				return fmt.Errorf("failed to restore database: %w", err)
 			}
 			current = ""
+
+			if err == io.EOF {
+				break
+			}
 		}
-		if err := scanner.Err(); err != nil {
-			return fmt.Errorf("failed to restore database: %w", err)
+		// if there's any leftover SQL (for example last statement without newline), execute it
+		if strings.TrimSpace(current) != "" {
+			if _, err := tx.Exec(current); err != nil {
+				_ = tx.Rollback()
+				return fmt.Errorf("failed to restore database: %w", err)
+			}
 		}
 		if err := tx.Commit(); err != nil {
 			return fmt.Errorf("failed to restore database: %w", err)