cilium/cilium · error

failed marshalling UUID to %v: %w

Error message

failed marshalling UUID to %v: %w

What it means

AdvertisePath marshals the UUID returned by gobgp's AddPath reply into the agent Path's UUID bytes via resp[0].UUID.MarshalBinary(). This error means the binary UUID marshalling failed - the reply's UUID is malformed or of an unexpected type/version.

Source

Thrown at pkg/bgp/gobgp/server.go:242

func (g *GoBGPServer) AdvertisePath(ctx context.Context, p types.PathRequest) (types.PathResponse, error) {
	gobgpPath, err := ToGoBGPPath(p.Path)
	if err != nil {
		return types.PathResponse{}, fmt.Errorf("failed converting Path to %v: %w", p.Path.NLRI, err)
	}

	resp, err := g.server.AddPath(apiutil.AddPathRequest{Paths: []*apiutil.Path{gobgpPath}})
	if err != nil {
		return types.PathResponse{}, fmt.Errorf("failed adding Path to %v: %w", gobgpPath.Nlri, err)
	}

	agentPath, err := ToAgentPath(gobgpPath)
	if err != nil {
		return types.PathResponse{}, fmt.Errorf("failed converting Path to %v: %w", gobgpPath.Nlri, err)
	}
	if len(resp) > 0 {
		agentPath.UUID, err = resp[0].UUID.MarshalBinary()
		if err != nil {
			return types.PathResponse{}, fmt.Errorf("failed marshalling UUID to %v: %w", gobgpPath.Nlri, err)
		}
	} else {
		return types.PathResponse{}, fmt.Errorf("empty AddPath reply for %v", gobgpPath.Nlri)
	}

	return types.PathResponse{
		Path: agentPath,
	}, err
}

// WithdrawPath withdraws a Path produced by AdvertisePath from this BgpServer.
func (g *GoBGPServer) WithdrawPath(ctx context.Context, p types.PathRequest) error {
	id, err := uuid.FromBytes(p.Path.UUID)
	if err != nil {
		return fmt.Errorf("failed converting UUID %v: %w", p.Path.UUID, err)
	}
	err = g.server.DeletePath(apiutil.DeletePathRequest{
		UUIDs: []uuid.UUID{id},

View on GitHub (pinned to ac7b90affa)

Solutions

1. Check the wrapped error to confirm the UUID length/type problem
2. Pin and align gobgp/api versions with the Cilium build (uuid.APIv1 vs v2 mismatches)
3. Restart/recreate the BGP server to get fresh, valid UUIDs from AddPath
4. If reproducible, file/report a bug - a valid AddPath reply should always carry a marshalable UUID

resp, err := srv.AdvertisePath(ctx, req)
if err != nil && strings.Contains(err.Error(), "failed marshalling UUID") {
    return fmt.Errorf("gobgp returned a corrupt UUID; check gobgp version pinning: %w", err)
}

When it happens

Trigger: AdvertisePath receives a non-empty AddPath reply whose first Path carries a UUID that fails MarshalBinary (wrong length, nil, or corrupt UUID from gobgp).

Common situations: gobgp library version skew where the UUID type changed; corrupted or uninitialized path UUIDs in the gobgp reply; extremely rare, usually indicates an internal bug or mismatched gobgp API version.

Related errors

• failed converting UUID %v: %w
• failed converting Path to %v: %w
• failed adding Path to %v: %w
• empty AddPath reply for %v
• nil policy in the RoutePolicyRequest

AI-assisted analysis of cilium/cilium@ac7b90affa (2026-08-31). Data as JSON: /api/errors/c75a700fcadbd6c1. Report an issue: GitHub.