---

title: Go sidebar_position: 6 id: go license: | Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Output Layout

Go output path depends on schema options and --go_out.

For addressbook.fdl, go_package is configured and generated output follows the configured import path/package (for example under your --go_out root).

Without go_package, output uses the requested --go_out directory and package-derived file naming.

Type Generation

Nested types use underscore naming by default (Person_PhoneType, Person_PhoneNumber):

type Person_PhoneType int32

const (
    Person_PhoneTypeMobile Person_PhoneType = 0
    Person_PhoneTypeHome   Person_PhoneType = 1
    Person_PhoneTypeWork   Person_PhoneType = 2
)

type Person_PhoneNumber struct {
    Number    string           `fory:"id=1"`
    PhoneType Person_PhoneType `fory:"id=2"`
}

Messages generate structs with fory tags and byte helpers:

type Person struct {
    Name   string               `fory:"id=1"`
    Id     int32                `fory:"id=2"`
    Phones []Person_PhoneNumber `fory:"id=7,type=list"`
    Pet    Animal               `fory:"id=8"`
}

func (m *Person) ToBytes() ([]byte, error) { ... }
func (m *Person) FromBytes(data []byte) error { ... }

Unions generate typed case structs with constructors/accessors/visitor APIs:

type AnimalCase uint32

type Animal struct {
    case_ AnimalCase
    value any
}

func DogAnimal(v *Dog) Animal { ... }
func CatAnimal(v *Cat) Animal { ... }

func (u Animal) Case() AnimalCase { ... }
func (u Animal) AsDog() (*Dog, bool) { ... }
func (u Animal) Visit(visitor AnimalVisitor) error { ... }

Registration

Generated registration function:

func RegisterTypes(f *fory.Fory) error {
    if err := f.RegisterUnion(Animal{}, 106, fory.NewUnionSerializer(...)); err != nil {
        return err
    }
    if err := f.RegisterEnum(Person_PhoneType(0), 101); err != nil {
        return err
    }
    if err := f.RegisterStruct(Person_PhoneNumber{}, 102); err != nil {
        return err
    }
    if err := f.RegisterStruct(Person{}, 100); err != nil {
        return err
    }
    return nil
}

For schemas without explicit [id=...], generated registration uses computed numeric IDs:

if err := f.RegisterEnum(Status(0), 1124725126); err != nil { ... }
if err := f.RegisterUnion(Wrapper{}, 1471345060, fory.NewUnionSerializer(...)); err != nil { ... }
if err := f.RegisterStruct(Envelope{}, 3022445236); err != nil { ... }
if err := f.RegisterUnion(Envelope_Detail{}, 1609214087, fory.NewUnionSerializer(...)); err != nil { ... }
if err := f.RegisterStruct(Envelope_Payload{}, 2862577837); err != nil { ... }

If option enable_auto_type_id = false; is set:

if err := f.RegisterStructByName(Config{}, "myapp.models.Config"); err != nil { ... }
if err := f.RegisterUnionByName(Holder{}, "myapp.models.Holder", fory.NewUnionSerializer(...)); err != nil { ... }

go_nested_type_style controls nested type naming:

option go_nested_type_style = "camelcase";

The CLI flag --go_nested_type_style overrides this schema option when both are set.

Usage

person := &Person{
    Name: "Alice",
    Pet:  DogAnimal(&Dog{Name: "Rex"}),
}

data, err := person.ToBytes()
if err != nil {
    panic(err)
}
var restored Person
if err := restored.FromBytes(data); err != nil {
    panic(err)
}

gRPC Service Companions

With --grpc, Go emits <module>_grpc.go containing the generated CodecV2, client and server interfaces, stream types, descriptors, and registration helpers. See Go gRPC for codec configuration and usage.