slackhq/nebula · error

invalid type: %T

Error message

invalid type: %T

What it means

Each entry within a calculated_remotes list must be a map (map[string]any) containing at least `mask` and `port` keys. newCalculatedRemotesEntryFromConfig throws this when an element of the list is any other type — e.g. a bare string, number, or nested list.

Source

Thrown at calculated_remote.go:129

		return nil, fmt.Errorf("calculated_remotes entry has invalid type: %T", raw)
	}

	var l []*calculatedRemote
	for _, e := range rawList {
		c, err := newCalculatedRemotesEntryFromConfig(cidr, e)
		if err != nil {
			return nil, fmt.Errorf("calculated_remotes entry: %w", err)
		}
		l = append(l, c)
	}

	return l, nil
}

func newCalculatedRemotesEntryFromConfig(cidr netip.Prefix, raw any) (*calculatedRemote, error) {
	rawMap, ok := raw.(map[string]any)
	if !ok {
		return nil, fmt.Errorf("invalid type: %T", raw)
	}

	rawValue := rawMap["mask"]
	if rawValue == nil {
		return nil, fmt.Errorf("missing mask: %v", rawMap)
	}
	rawMask, ok := rawValue.(string)
	if !ok {
		return nil, fmt.Errorf("invalid mask (type %T): %v", rawValue, rawValue)
	}
	maskCidr, err := netip.ParsePrefix(rawMask)
	if err != nil {
		return nil, fmt.Errorf("invalid mask: %s", rawMask)
	}

	var port int
	rawValue = rawMap["port"]
	if rawValue == nil {

View on GitHub (pinned to dd8f660c0a)

Solutions

  1. Restructure each list element as a map with `mask` and `port` keys
  2. Check the %T in the message to see what the element parsed as (string, float64, etc.)
  3. Fix YAML indentation so each entry is a mapping under the CIDR's list

Example fix

// before
lighthouse:
  calculated_remotes:
    10.0.42.0/24:
      - 10.0.0.0/8
// after
lighthouse:
  calculated_remotes:
    10.0.42.0/24:
      - mask: 10.0.0.0/8
        port: 4242
Defensive patterns

Strategy: type-guard

Validate before calling

for _, e := range list {
	if _, ok := e.(map[string]any); !ok {
		return fmt.Errorf("each entry must be a mask/port map")
	}
}

Type guard

func isEntryMap(v any) bool {
	_, ok := v.(map[string]any)
	return ok
}

Try / catch

if err != nil {
	if strings.Contains(err.Error(), "invalid type: ") {
		return fmt.Errorf("calculated_remotes entries must be objects with mask+port: %w", err)
	}
	return err
}

Prevention

When it happens

Trigger: A calculated_remotes list element like `- 10.0.0.0/8` (bare string instead of a mask/port map), or a list nested inside a list from bad YAML indentation.

Common situations: Users listing masks directly without mask/port keys, or mis-indented YAML that turns entries into scalars; common when hand-editing nebula configs.

Related errors

AI-assisted analysis of slackhq/nebula@dd8f660c0a (2026-09-03). Data as JSON: /api/errors/e43f636b96af960d. Report an issue: GitHub.