OpenNHP/opennhp · error

nhp server length is too long

Error message

nhp server length is too long

What it means

SetNhpServer stores the NHP server identity into the ZtdoHeader. The header reserves a single byte (NhpServerLen) for the server string length, capping it at NhpServerMaxSize bytes. Longer strings return this error instead of silently truncating.

Solutions

1. Shorten the nhp server string (use a shorter hostname; check it against NhpServerMaxSize bytes, not characters)
2. Move port/scheme out of the field if possible
3. Validate the length before constructing the header and fail config load early with a clearer message

Example fix

// before
if len(nhpServer) > NhpServerMaxSize {
	return fmt.Errorf("nhp server length is too long")
}
// after
if len(nhpServer) > NhpServerMaxSize {
	return fmt.Errorf("nhp server %q is %d bytes, max is %d", nhpServer, len(nhpServer), NhpServerMaxSize)
}

if len(nhpServer) > NhpServerMaxSize {
	return fmt.Errorf("nhp server must be at most %d bytes, got %d", NhpServerMaxSize, len(nhpServer))
}

if err := header.SetNhpServer(server); err != nil {
	if strings.Contains(err.Error(), "nhp server length is too long") {
		// shorten hostname or reject config
	}
	return err
}

When it happens

Trigger: Calling ZtdoHeader.SetNhpServer with a string longer than NhpServerMaxSize bytes (nhp/core/ztdo/ztdo.go:121). Called from runApp and recursively via SetNhpServer wrappers.

Common situations: Configuring long FQDNs or "host:port" with IPv6 literal addresses exceeding the byte limit; concatenating scheme + host + port into the server field.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

• unsupported protocol
• cluster instance # : must set either Host or Ip
• cluster instance # : invalid port
• AuthServiceId is required
• invalid digit count

AI-assisted analysis of OpenNHP/opennhp@6e04ca5ff0 (2026-09-07). Data as JSON: /api/errors/16a8caec5b95df0b. Report an issue: GitHub.

Appendix: source

Thrown at nhp/core/ztdo/ztdo.go:121

	// generate uuid
	uuid := uuid.New()
	header.ObjectID = [ObjectIDSize]byte(uuid)

	// User first 4 bytes to set magic number
	header.MagicNumber = [MagicNumberSize]byte(uuid[0:4])
}

func (header *ZtdoHeader) GetObjectID() string {
	return uuid.UUID(header.ObjectID).String()
}

func (header *ZtdoHeader) SetVersion() {
	header.Version = [VersionSize]byte{0x00, 0x01}
}

func (header *ZtdoHeader) SetNhpServer(nhpServer string) error {
	if len(nhpServer) > NhpServerMaxSize {
		return fmt.Errorf("nhp server length is too long")
	}

	header.NhpServerLen[0] = byte(len(nhpServer))
	header.NhpServer = []byte(nhpServer)

	return nil
}

// SetMetadata supports variable length of metadata
func (header *ZtdoHeader) SetMetadata(metadata string) error {
	header.Metadata = []ZtdoMetadata{}

	totalLen := len(metadata)
	chunkNum := totalLen / MetadataChunkMaxSize

	for i := 0; i < chunkNum; i++ {
		chunk := metadata[i*MetadataChunkMaxSize : (i+1)*MetadataChunkMaxSize]
		chunkEncodedLen, err := encodeMetadataLength(len(chunk), true)

View on GitHub (pinned to 6e04ca5ff0)