add tool to recover unhealthy DBs

tools/db-recovery/main.go

+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/iotaledger/goshimmer/packages/database"
+	"github.com/iotaledger/goshimmer/packages/database/prefix"
+	flag "github.com/spf13/pflag"
+	"github.com/spf13/viper"
+)
+
+const (
+	cfgDatabaseDir = "database"
+)
+
+func init() {
+	flag.String(cfgDatabaseDir, "mainnetdb", "path to the database folder")
+}
+
+func main() {
+
+	if err := run(); err != nil {
+		fmt.Fprintf(os.Stderr, "Error: %s\n", err)
+		os.Exit(1)
+	}
+}
+
+func run() error {
+	flag.Parse()
+	err := viper.BindPFlags(flag.CommandLine)
+	if err != nil {
+		return err
+	}
+
+	dbDir := viper.GetString(cfgDatabaseDir)
+	ok, err := exists(dbDir)
+	if err != nil {
+		return err
+	}
+	if !ok {
+		return fmt.Errorf("database folder does not exist: %s", dbDir)
+	}
+
+	db, err := database.NewDB(dbDir)
+	if err != nil {
+		return err
+	}
+
+	healthStore := db.NewStore().WithRealm([]byte{prefix.DBPrefixHealth})
+	return healthStore.Delete([]byte("db_health"))
+}
+
+func exists(path string) (bool, error) {
+	_, err := os.Stat(path)
+	if os.IsNotExist(err) {
+		return false, nil
+	}
+	if err != nil {
+		return false, err
+	}
+	return true, err
+}