Full node metadata backup

node/impl/backup.go

@@ -0,0 +1,67 @@
+package impl
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/mitchellh/go-homedir"
+	"golang.org/x/xerrors"
+
+	"github.com/filecoin-project/lotus/lib/backupds"
+	"github.com/filecoin-project/lotus/node/modules/dtypes"
+)
+
+func backup(mds dtypes.MetadataDS, fpath string) error {
+	bb, ok := os.LookupEnv("LOTUS_BACKUP_BASE_PATH")
+	if !ok {
+		return xerrors.Errorf("LOTUS_BACKUP_BASE_PATH env var not set")
+	}
+
+	bds, ok := mds.(*backupds.Datastore)
+	if !ok {
+		return xerrors.Errorf("expected a backup datastore")
+	}
+
+	bb, err := homedir.Expand(bb)
+	if err != nil {
+		return xerrors.Errorf("expanding base path: %w", err)
+	}
+
+	bb, err = filepath.Abs(bb)
+	if err != nil {
+		return xerrors.Errorf("getting absolute base path: %w", err)
+	}
+
+	fpath, err = homedir.Expand(fpath)
+	if err != nil {
+		return xerrors.Errorf("expanding file path: %w", err)
+	}
+
+	fpath, err = filepath.Abs(fpath)
+	if err != nil {
+		return xerrors.Errorf("getting absolute file path: %w", err)
+	}
+
+	if !strings.HasPrefix(fpath, bb) {
+		return xerrors.Errorf("backup file name (%s) must be inside base path (%s)", fpath, bb)
+	}
+
+	out, err := os.OpenFile(fpath, os.O_CREATE|os.O_WRONLY, 0644)
+	if err != nil {
+		return xerrors.Errorf("open %s: %w", fpath, err)
+	}
+
+	if err := bds.Backup(out); err != nil {
+		if cerr := out.Close(); cerr != nil {
+			log.Errorw("error closing backup file while handling backup error", "closeErr", cerr, "backupErr", err)
+		}
+		return xerrors.Errorf("backup error: %w", err)
+	}
+
+	if err := out.Close(); err != nil {
+		return xerrors.Errorf("closing backup file: %w", err)
+	}
+
+	return nil
+}