canopy-network/canopy · error

rotate backup: %w

Error message

rotate backup: %w

What it means

Wrapped failure (fmt.Errorf with %w) around os.Rename when rotating the previous backup directory out of the way (backupDir -> prevBackupDir) during backup finalization. On Unix this is atomic; failures indicate path problems, permissions, or cross-device rename issues in the backup rotation scheme.

Source

Thrown at store/store.go:795

			s.mu.Unlock()
			err = fmt.Errorf("flush before checkpoint: %w", err)
			return
		}
		s.mu.Unlock()
		// perform the backup using pebble's checkpointing mechanism which creates a
		// consistent snapshot of the database at the specified directory
		if err = s.db.Checkpoint(tempBackupDir); err != nil {
			err = fmt.Errorf("checkpoint creation: %w", err)
			return
		}
		// write the current height to a separate file
		heightFile := filepath.Join(tempBackupDir, "height.txt")
		if err = os.WriteFile(heightFile, fmt.Appendf(nil, "%d", version), 0644); err != nil {
			err = fmt.Errorf("write height file: %w", err)
			return
		}
		if err = os.Rename(backupDir, prevBackupDir); err != nil && !os.IsNotExist(err) {
			err = fmt.Errorf("rotate backup: %w", err)
			return
		}
		// promote: atomically move the temp backup into the active slot
		if err = os.Rename(tempBackupDir, backupDir); err != nil {
			err = fmt.Errorf("finalize backup: %w", err)
			return
		}
		backupDuration := time.Since(start)
		// log results
		s.log.Infof("backup completed at height [%d] in %s", version, backupDuration)
		// update metrics
		s.metrics.UpdateStoreJobMetrics(0, 0, backupDuration)
	}()
}

// Compact runs Pebble range compaction over the prefix range
func (s *Store) Compact(version uint64, prefix []byte) lib.ErrorI {
	// compactions are not allowed to run concurrently to not intertwine with the keys

View on GitHub (pinned to ee8197d91d)

Solutions

1. Verify backupDir and prevBackupDir are on the same filesystem (os.Rename fails across devices).
2. Remove stale prevBackupDir if a prior crashed rotation left it in a conflicting state.
3. Check parent-directory write permissions needed for the rename.

When it happens

Trigger: Thrown at store/store.go:795 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of canopy-network/canopy@ee8197d91d (2026-09-06). Data as JSON: /api/errors/7c28673b0327a5f4. Report an issue: GitHub.