protoc-gen-gin.rar

难点：
插件是属于被protoc调用的工具， 所以无法单独启动，很难调试
protoc插件运行需要一些输入，这些输入是由protoc传递过来放入os.Stdin中
插件的输入是到stdout而不是由我们自己确定的，所以很难输出文件查看生成效果

注意：
下面属于魔改源码使得为了方便调试，所以本着尽量少改源码的方式去修改

修改源码 protobuf/compiler/protogen/protogen.go

1. 新增函数

   func fileDescriptorProto(files …string) (*descriptorpb.FileDescriptorProto, error) {

   var p protoparse.Parser
   fd, err := p.ParseFiles(files...)
   if err != nil {
       return nil, err
   }
   return fd[0].AsFileDescriptorProto(), nil

   }

b. 修改func run(opts Options, f func(*Plugin) error) 函数

import "github.com/jhump/protoreflect/desc/protoparse"
func runV2(opts Options, f func(*Plugin) error) error {
    if len(os.Args) > 1 {
        return fmt.Errorf("unknown argument %q (this program should be run by protoc, not directly)", os.Args[1])
    }
    fileName := "E:/xxx/api.proto"
    fdpb, err := fileDescriptorProto(fileName)
    if err != nil {
        panic(err)
    }
    req1 := []*descriptorpb.FileDescriptorProto{fdpb}
    req := &pluginpb.CodeGeneratorRequest{
        ProtoFile: req1,
        FileToGenerate: []string{fileName},
    }
    gen, err := opts.New(req)
    if err != nil {
        return err
    }

1. New函数中增加一行

   func (opts Options) New(req pluginpb.CodeGeneratorRequest) (Plugin, error) {

   //新增
   gen.fileReg = protoregistry.GlobalFiles

   }

导入相关proto文件

1. 需要将third_party中依赖的google相关的proto文件拷贝到工具目录下
2. 在goland的运行配置中设置当前运行目录为 E:/myprojects/gostart/tools 要和main文件在同一个目录下

自定义注册proto源码

package main
import (
    "flag"
    "google.golang.org/protobuf/reflect/protodesc"
    "google.golang.org/protobuf/reflect/protoregistry"
    "google.golang.org/protobuf/types/descriptorpb"
    "io/ioutil"
    "os"
    "os/exec"
    "path"
    "github.com/golang/protobuf/proto"
    "google.golang.org/protobuf/compiler/protogen"
    "google.golang.org/protobuf/types/pluginpb"
)
func registerProtoFile(srcDir string, filename string) error {
    // First, convert the .proto file to a file descriptor set.
    tmpFile := path.Join(srcDir, filename+".pb")
    cmd := exec.Command("protoc",
        "--include_source_info",
        "--descriptor_set_out="+tmpFile,
        "--proto_path="+srcDir,
        path.Join(srcDir, filename))
    cmd.Stdout = os.Stdout
    cmd.Stderr = os.Stderr
    err := cmd.Run()
    if err != nil {
        panic(err)
    }
    defer os.Remove(tmpFile)
    // Now load that temporary file as a file descriptor set protobuf.
    protoFile, err := ioutil.ReadFile(tmpFile)
    if err != nil {
        panic(err)
    }
    pbSet := new(descriptorpb.FileDescriptorSet)
    if err := proto.Unmarshal(protoFile, pbSet); err != nil {
        panic(err)
    }
    // We know protoc was invoked with a single .proto file.
    pb := pbSet.GetFile()[0]
    // Initialize the file descriptor object.
    fd, err := protodesc.NewFile(pb, protoregistry.GlobalFiles)
    if err != nil {
        panic(err)
    }
    // and finally register it.
    return protoregistry.GlobalFiles.RegisterFile(fd)
}
func registerProto() {
    files := []string{
        "google/api/http.proto",
        "google/api/annotations.proto",
        "google/api/client.proto",
        "google/api/field_behavior.proto",
        "google/api/resource.proto",
    }
    for _, f := range files {
        err := registerProtoFile("./", f)
        if err != nil {
            panic(err)
        }
    }
}
func main() {
    registerProto()
    flag.Parse()
    var flags flag.FlagSet
    protogen.Options{
        ParamFunc: flags.Set,
    }.Run(func(gen *protogen.Plugin) error {
        gen.SupportedFeatures = uint64(pluginpb.CodeGeneratorResponse_FEATURE_PROTO3_OPTIONAL)
        for _, f := range gen.Files {
            if !f.Generate {
                continue
            }
            //generateFile(gen, f)
        }
        return nil
    })
}