docker/cli · error

invalid proto, expected %s: %s

Error message

invalid proto, expected %s: %s

What it means

Error "invalid proto, expected %s: %s" thrown in docker/cli.

Source

Thrown at opts/hosts.go:86

	case "npipe":
		return parseSimpleProtoAddr(proto, host, defaultNamedPipe)
	case "fd":
		return addr, nil
	case "ssh":
		return addr, nil
	default:
		return "", fmt.Errorf("invalid bind address format: %s", addr)
	}
}

// parseSimpleProtoAddr parses and validates that the specified address is a valid
// socket address for simple protocols like unix and npipe. It returns a formatted
// socket address, either using the address parsed from addr, or the contents of
// defaultAddr if addr is a blank string.
func parseSimpleProtoAddr(proto, addr, defaultAddr string) (string, error) {
	addr = strings.TrimPrefix(addr, proto+"://")
	if strings.Contains(addr, "://") {
		return "", fmt.Errorf("invalid proto, expected %s: %s", proto, addr)
	}
	if addr == "" {
		addr = defaultAddr
	}
	return fmt.Sprintf("%s://%s", proto, addr), nil
}

// ParseTCPAddr parses and validates that the specified address is a valid TCP
// address. It returns a formatted TCP address, either using the address parsed
// from tryAddr, or the contents of defaultAddr if tryAddr is a blank string.
// tryAddr is expected to have already been Trim()'d
// defaultAddr must be in the full `tcp://host:port` form
func ParseTCPAddr(tryAddr string, defaultAddr string) (string, error) {
	if tryAddr == "" || tryAddr == "tcp://" {
		return defaultAddr, nil
	}
	addr := strings.TrimPrefix(tryAddr, "tcp://")
	if strings.Contains(addr, "://") || addr == "" {

View on GitHub (pinned to e9452d6e78)

When it happens

Trigger: Thrown at opts/hosts.go:86 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of docker/cli@e9452d6e78 (2026-08-01). Data as JSON: /data/errors/d16d709f844ddff2.json. Report an issue: GitHub.