Only take a backup of the redis/keydb master (#67)

cmd/internal/database/redis/redis.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"path"
+	"strings"
 	"time"
 
 	"github.com/redis/go-redis/v9"
@@ -53,6 +54,15 @@ func New(log *zap.SugaredLogger, datadir string, addr string, password *string)
 
 // Backup takes a dump of redis with the redis client.
 func (db *Redis) Backup(ctx context.Context) error {
+	isMaster, err := db.isMaster(ctx)
+	if err != nil {
+		return err
+	}
+	if !isMaster {
+		db.log.Info("this database is not master, not taking a backup")
+		return nil
+	}
+
 	if err := os.RemoveAll(constants.BackupDir); err != nil {
 		return fmt.Errorf("could not clean backup directory: %w", err)
 	}
@@ -62,7 +72,7 @@ func (db *Redis) Backup(ctx context.Context) error {
 	}
 
 	start := time.Now()
-	_, err := db.client.Save(ctx).Result()
+	_, err = db.client.Save(ctx).Result()
 	if err != nil {
 		return fmt.Errorf("could not create a dump: %w", err)
 	}
@@ -147,3 +157,15 @@ func (db *Redis) Recover(ctx context.Context) error {
 func (db *Redis) Upgrade(_ context.Context) error {
 	return nil
 }
+
+func (db *Redis) isMaster(ctx context.Context) (bool, error) {
+	info, err := db.client.Info(ctx, "replication").Result()
+	if err != nil {
+		return false, fmt.Errorf("unable to get database info %w", err)
+	}
+	if strings.Contains(info, "role:master") {
+		db.log.Info("this is database master")
+		return true, nil
+	}
+	return false, nil
+}