Question

我正在尝试遵循有关ProtoBufs的本教程：https://developers.google.com/protocol-buffers/docs/gotutorial。我有以下项目结构：

.
├── addressbook
│   ├── addressbook.pb.go
│   └── addressbook.proto
├── go.mod
├── go.sum
└── main.go

addressbook.proto在哪里

syntax = "proto3";
package addressbook;

import "google/protobuf/timestamp.proto";

message Person {
    string name = 1;
    int32 id = 2;
    string email = 3;

    enum PhoneType {
        MOBILE = 0;
        HOME = 1;
        WORK = 2;
    }

    message PhoneNumber {
        string number = 1;
        PhoneType type = 2;
    }

    repeated PhoneNumber phones = 4;

    google.protobuf.Timestamp last_updated = 5;
}

message AddressBook {
    repeated Person people = 1;
}

和自动生成的（带有protoc addressbook.proto --go-out=.）addressbook.pb.go读取

// Code generated by protoc-gen-go. DO NOT EDIT.
// source: addressbook.proto

package addressbook

import (
    fmt "fmt"
    proto "github.com/golang/protobuf/proto"
    timestamp "github.com/golang/protobuf/ptypes/timestamp"
    math "math"
)

// Reference imports to suppress errors if they are not otherwise used.
var _ = proto.Marshal
var _ = fmt.Errorf
var _ = math.Inf

// This is a compile-time assertion to ensure that this generated file
// is compatible with the proto package it is being compiled against.
// A compilation error at this line likely means your copy of the
// proto package needs to be updated.
const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package

type Person_PhoneType int32

const (
    Person_MOBILE Person_PhoneType = 0
    Person_HOME   Person_PhoneType = 1
    Person_WORK   Person_PhoneType = 2
)

var Person_PhoneType_name = map[int32]string{
    0: "MOBILE",
    1: "HOME",
    2: "WORK",
}

var Person_PhoneType_value = map[string]int32{
    "MOBILE": 0,
    "HOME":   1,
    "WORK":   2,
}

func (x Person_PhoneType) String() string {
    return proto.EnumName(Person_PhoneType_name, int32(x))
}

func (Person_PhoneType) EnumDescriptor() ([]byte, []int) {
    return fileDescriptor_1eb1a68c9dd6d429, []int{0, 0}
}

type Person struct {
    Name                 string                `protobuf:"bytes,1,opt,name=name,proto3" json:"name,omitempty"`
    Id                   int32                 `protobuf:"varint,2,opt,name=id,proto3" json:"id,omitempty"`
    Email                string                `protobuf:"bytes,3,opt,name=email,proto3" json:"email,omitempty"`
    Phones               []*Person_PhoneNumber `protobuf:"bytes,4,rep,name=phones,proto3" json:"phones,omitempty"`
    LastUpdated          *timestamp.Timestamp  `protobuf:"bytes,5,opt,name=last_updated,json=lastUpdated,proto3" json:"last_updated,omitempty"`
    XXX_NoUnkeyedLiteral struct{}              `json:"-"`
    XXX_unrecognized     []byte                `json:"-"`
    XXX_sizecache        int32                 `json:"-"`
}

func (m *Person) Reset()         { *m = Person{} }
func (m *Person) String() string { return proto.CompactTextString(m) }
func (*Person) ProtoMessage()    {}
func (*Person) Descriptor() ([]byte, []int) {
    return fileDescriptor_1eb1a68c9dd6d429, []int{0}
}

func (m *Person) XXX_Unmarshal(b []byte) error {
    return xxx_messageInfo_Person.Unmarshal(m, b)
}
func (m *Person) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
    return xxx_messageInfo_Person.Marshal(b, m, deterministic)
}
func (m *Person) XXX_Merge(src proto.Message) {
    xxx_messageInfo_Person.Merge(m, src)
}
func (m *Person) XXX_Size() int {
    return xxx_messageInfo_Person.Size(m)
}
func (m *Person) XXX_DiscardUnknown() {
    xxx_messageInfo_Person.DiscardUnknown(m)
}

var xxx_messageInfo_Person proto.InternalMessageInfo

func (m *Person) GetName() string {
    if m != nil {
        return m.Name
    }
    return ""
}

func (m *Person) GetId() int32 {
    if m != nil {
        return m.Id
    }
    return 0
}

func (m *Person) GetEmail() string {
    if m != nil {
        return m.Email
    }
    return ""
}

func (m *Person) GetPhones() []*Person_PhoneNumber {
    if m != nil {
        return m.Phones
    }
    return nil
}

func (m *Person) GetLastUpdated() *timestamp.Timestamp {
    if m != nil {
        return m.LastUpdated
    }
    return nil
}

type Person_PhoneNumber struct {
    Number               string           `protobuf:"bytes,1,opt,name=number,proto3" json:"number,omitempty"`
    Type                 Person_PhoneType `protobuf:"varint,2,opt,name=type,proto3,enum=addressbook.Person_PhoneType" json:"type,omitempty"`
    XXX_NoUnkeyedLiteral struct{}         `json:"-"`
    XXX_unrecognized     []byte           `json:"-"`
    XXX_sizecache        int32            `json:"-"`
}

func (m *Person_PhoneNumber) Reset()         { *m = Person_PhoneNumber{} }
func (m *Person_PhoneNumber) String() string { return proto.CompactTextString(m) }
func (*Person_PhoneNumber) ProtoMessage()    {}
func (*Person_PhoneNumber) Descriptor() ([]byte, []int) {
    return fileDescriptor_1eb1a68c9dd6d429, []int{0, 0}
}

func (m *Person_PhoneNumber) XXX_Unmarshal(b []byte) error {
    return xxx_messageInfo_Person_PhoneNumber.Unmarshal(m, b)
}
func (m *Person_PhoneNumber) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
    return xxx_messageInfo_Person_PhoneNumber.Marshal(b, m, deterministic)
}
func (m *Person_PhoneNumber) XXX_Merge(src proto.Message) {
    xxx_messageInfo_Person_PhoneNumber.Merge(m, src)
}
func (m *Person_PhoneNumber) XXX_Size() int {
    return xxx_messageInfo_Person_PhoneNumber.Size(m)
}
func (m *Person_PhoneNumber) XXX_DiscardUnknown() {
    xxx_messageInfo_Person_PhoneNumber.DiscardUnknown(m)
}

var xxx_messageInfo_Person_PhoneNumber proto.InternalMessageInfo

func (m *Person_PhoneNumber) GetNumber() string {
    if m != nil {
        return m.Number
    }
    return ""
}

func (m *Person_PhoneNumber) GetType() Person_PhoneType {
    if m != nil {
        return m.Type
    }
    return Person_MOBILE
}

type AddressBook struct {
    People               []*Person `protobuf:"bytes,1,rep,name=people,proto3" json:"people,omitempty"`
    XXX_NoUnkeyedLiteral struct{}  `json:"-"`
    XXX_unrecognized     []byte    `json:"-"`
    XXX_sizecache        int32     `json:"-"`
}

func (m *AddressBook) Reset()         { *m = AddressBook{} }
func (m *AddressBook) String() string { return proto.CompactTextString(m) }
func (*AddressBook) ProtoMessage()    {}
func (*AddressBook) Descriptor() ([]byte, []int) {
    return fileDescriptor_1eb1a68c9dd6d429, []int{1}
}

func (m *AddressBook) XXX_Unmarshal(b []byte) error {
    return xxx_messageInfo_AddressBook.Unmarshal(m, b)
}
func (m *AddressBook) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
    return xxx_messageInfo_AddressBook.Marshal(b, m, deterministic)
}
func (m *AddressBook) XXX_Merge(src proto.Message) {
    xxx_messageInfo_AddressBook.Merge(m, src)
}
func (m *AddressBook) XXX_Size() int {
    return xxx_messageInfo_AddressBook.Size(m)
}
func (m *AddressBook) XXX_DiscardUnknown() {
    xxx_messageInfo_AddressBook.DiscardUnknown(m)
}

var xxx_messageInfo_AddressBook proto.InternalMessageInfo

func (m *AddressBook) GetPeople() []*Person {
    if m != nil {
        return m.People
    }
    return nil
}

func init() {
    proto.RegisterEnum("addressbook.Person_PhoneType", Person_PhoneType_name, Person_PhoneType_value)
    proto.RegisterType((*Person)(nil), "addressbook.Person")
    proto.RegisterType((*Person_PhoneNumber)(nil), "addressbook.Person.PhoneNumber")
    proto.RegisterType((*AddressBook)(nil), "addressbook.AddressBook")
}

func init() { proto.RegisterFile("addressbook.proto", fileDescriptor_1eb1a68c9dd6d429) }

var fileDescriptor_1eb1a68c9dd6d429 = []byte{
    // 309 bytes of a gzipped FileDescriptorProto
    0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x74, 0x90, 0x41, 0x4b, 0xc3, 0x40,
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    0xfd, 0x1c, 0xab, 0xac, 0x20, 0xa9, 0xe2, 0x42, 0x18, 0x7a, 0xf8, 0x6d, 0x83, 0xbb, 0xa4, 0x4a,
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    0x76, 0xc9, 0x01, 0x00, 0x00,
}

我正在main.go中尝试此脚本：

package main

import (
    "fmt"

    "github.com/gogo/protobuf/proto"
    "github.com/kurtpeek/addressbook/addressbook"
    "github.com/sirupsen/logrus"
)

func main() {
    person := addressbook.Person{
        Name:  "Boba Fett",
        Email: "boba.fett@gmail.com",
        Phones: []*addressbook.Person_PhoneNumber{
            &addressbook.Person_PhoneNumber{
                Number: "4158666171",
                Type:   addressbook.Person_MOBILE,
            },
        },
    }
    book := addressbook.AddressBook{
        People: []*addressbook.Person{&person},
    }

    _, err := proto.Marshal(book)
    if err != nil {
        logrus.WithError(err).Fatal("marshal to ProtoBuf")
    }
    fmt.Printf("%+v\n", person)
}

问题是，当我尝试运行此命令时，我得到一个错误，提示AddressBook没有实现Message接口：

> go run main.go
# command-line-arguments
./main.go:26:25: cannot use book (type addressbook.AddressBook) as type "github.com/gogo/protobuf/proto".Message in argument to "github.com/gogo/protobuf/proto".Marshal:
    addressbook.AddressBook does not implement "github.com/gogo/protobuf/proto".Message (ProtoMessage method has pointer receiver)

转到Message的定义，我发现以下接口：

// Message is implemented by generated protocol buffer messages.
type Message interface {
    Reset()
    String() string
    ProtoMessage()
}

从addressbook.pg.go看来AddressBook实现了这三种方法，所以我不明白为什么我得到了错误消息？

这是我的go.mod，

module github.com/kurtpeek/addressbook

go 1.12

require (
    github.com/gogo/protobuf v1.3.1
    github.com/golang/protobuf v1.3.2
    github.com/sirupsen/logrus v1.4.2
)

这是我的protoc版本（我使用protoc安装了brew install protobuf）：

> protoc --version
libprotoc 3.11.1

Answer 1

在创建像这样的书之前，您需要传递指向proto.Marshal（）的指针，或者做proto.Marshal(&book)或已经创建指针：

book := &addressbook.AddressBook{
             People: []*addressbook.Person{&person},
        }

请参阅第一行中的＆

Answer 2

这是API版本的问题。

From the go blog

github.com/golang/protobuf模块是APIv1。 google.golang.org/protobuf模块是APIv2。我们利用了需要更改导入路径以切换到与特定主机提供商无关的路径的优势。（我们考虑了google.golang.org/protobuf/v2，以明确表明这是API的第二个主要版本，但从长远来看，它是长期的最佳选择。）

因此，为了方便运行代码，请使用“ github.com/golang/protobuf/proto”而不是“ github.com/gogo/protobuf/proto”来实现编组功能。问题出在新的api protoreflect。查看文章。

您可以选择使用“ google.golang.org/protobuf”，但我的建议是使用“ github.com/golang/protobuf/proto”。您可以详细了解两个here的区别。

ProtoBuf教程：“地址簿未实现“ github.com/gogo/protobuf/proto”。消息（ProtoMessage方法具有指针接收器）”

2 个答案: