Function writeExportMetadata

usecases/export/scheduler.go:821–865

writeExportMetadata writes the given ExportMetadata to the storage backend with retries. It uses a fresh context with a timeout so the write succeeds even if the original context was canceled.

(
	backend modulecapabilities.BackupBackend,
	exportID, bucket, path string,
	metadata *ExportMetadata,
	logger logrus.FieldLogger,
)

// with retries. It uses a fresh context with a timeout so the write succeeds
// even if the original context was canceled.
func writeExportMetadata(
	backend modulecapabilities.BackupBackend,
	exportID, bucket, path string,
	metadata *ExportMetadata,
	logger logrus.FieldLogger,
) error {
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	// Ensure CompletedAt is always set for terminal metadata so the file
	// has a meaningful timestamp even when no node reported a completion
	// time (e.g. all nodes crashed or the export was canceled/shut down).
	if metadata.CompletedAt.IsZero() {
		switch metadata.Status {
		case export.Success, export.Failed, export.Canceled:
			metadata.CompletedAt = time.Now().UTC()
		case export.Started, export.Transferring:
			// Non-terminal — no CompletedAt needed.
		}
	}

	data, err := json.MarshalIndent(metadata, "", "  ")
	if err != nil {
		return fmt.Errorf("marshal metadata: %w", err)
	}

	const maxRetries = 3
	for attempt := range maxRetries {
		_, err = backend.Write(ctx, exportID, exportMetadataFile, bucket, path, newBytesReadCloser(data))
		if err == nil {
			return nil
		}
		if attempt < maxRetries-1 {
			logger.WithField("action", "export_write_metadata").
				WithField("export_id", exportID).
				Warnf("metadata write attempt %d failed, retrying: %v", attempt+1, err)
			select {
			case <-ctx.Done():
				return fmt.Errorf("write metadata aborted after %d attempts: %w", attempt+1, ctx.Err())
			case <-time.After(500 * time.Millisecond):
			}
		}
	}
	return fmt.Errorf("write metadata after %d attempts: %w", maxRetries, err)
}

// readNodeStatus reads and unmarshals a node's status file from the storage backend.
func readNodeStatus(ctx context.Context, backend modulecapabilities.BackupBackend, exportID, bucket, path, nodeName string) (*NodeStatus, error) {