feat: add in-file transport protocol specification for protoc-gen-go-dubbo

README.md

@@ -28,6 +28,15 @@ protoc -I ./ \
 The `--go-dubbo_out` option specifies the output directory for the generated code,
 and `--go-dubbo_opt=paths=source_relative` sets the output path to be relative to the source file.
 
+You can also use the flags `in_file_method_protocol_spec=true` or `in_file_method_protocol_spec=true` to enable in-file transport protocol specification, then protoc-gen-go-dubbo will only generate the service/method with the option "DUBBO". For example:
+
+```shell
+protoc -I ./ \
+  --go-hessian2_out=./ --go-hessian2_opt=paths=source_relative \
+  --go-dubbo_out=./ --go-dubbo_opt=paths=source_relative,in_file_method_protocol_spec=true \
+  ./greet.proto
+```
+
 ## Example
 To generate Dubbo code, you can create a `.proto` file with the following content:
 ```protobuf
@@ -63,6 +72,50 @@ service GreetService {
   }
 }
 ```
+
+Extra options with transport protocol specification look like the follows:
+
+```proto
+//method protocol spec
+service GreetingsService  {
+  rpc Greet(GreetRequest) returns (GreetResponse) {
+    option (unified_idl_extend.method_protocols) = {
+      protocol_names: ["DUBBO"];
+    };
+    option (unified_idl_extend.method_extend) = {
+      method_name: "greet";
+    };
+  }
+  rpc Greet2(GreetRequest) returns (GreetResponse) {
+    option (unified_idl_extend.method_protocols) = {
+      protocol_names: ["TRIPLE","DUBBO"];
+    };
+    option (unified_idl_extend.method_extend) = {
+      method_name: "greet2";
+    };
+  }
+}
+```
+
+```proto
+service GreetingsService  {
+//service protocol spec
+option (unified_idl_extend.service_protocol) = {
+    protocol_name: "DUBBO";
+  };
+  rpc Greet(GreetRequest) returns (GreetResponse) {
+    option (unified_idl_extend.method_extend) = {
+      method_name: "greet";
+    };
+  }
+  rpc Greet2(GreetRequest) returns (GreetResponse) {
+    option (unified_idl_extend.method_extend) = {
+      method_name: "greet2";
+    };
+  }
+}
+```
+
 Note that you need to import the `unified_idl_extend` package to use the `method_extend` options to extend the service.
 And Dubbo protocol must be used with Hessian2 serialization, so you need to use the `message_extend` options to extend 
 the message.

generator/gen_dubbo.go

@@ -19,19 +19,14 @@ package generator
 
 import (
 	"fmt"
-)
 
-import (
+	"github.com/dubbogo/protoc-gen-go-dubbo/proto/unified_idl_extend"
+	"github.com/dubbogo/protoc-gen-go-dubbo/util"
 	"github.com/pkg/errors"
 	"google.golang.org/protobuf/compiler/protogen"
 	"google.golang.org/protobuf/proto"
 )
 
-import (
-	"github.com/dubbogo/protoc-gen-go-dubbo/proto/unified_idl_extend"
-	"github.com/dubbogo/protoc-gen-go-dubbo/util"
-)
-
 var (
 	ErrStreamMethod               = errors.New("dubbo doesn't support stream method")
 	ErrMoreExtendArgsRespFieldNum = errors.New("extend args for response message should only has 1 field")
@@ -66,7 +61,7 @@ type Method struct {
 	ReturnType         string
 }
 
-func ProcessProtoFile(g *protogen.GeneratedFile, file *protogen.File) (*Dubbogo, error) {
+func ProcessProtoFile(g *protogen.GeneratedFile, file *protogen.File, methodProtocolSpecFlag, serviceProtocolSpecFlag bool) (*Dubbogo, error) {
 	desc := file.Proto
 	dubboGo := &Dubbogo{
 		File:         file,
@@ -76,7 +71,15 @@ func ProcessProtoFile(g *protogen.GeneratedFile, file *protogen.File) (*Dubbogo,
 	}
 
 	for _, service := range file.Services {
+		serviceProtocolOpt, ok := proto.GetExtension(service.Desc.Options(), unified_idl_extend.E_ServiceProtocol).(*unified_idl_extend.ServiceProtocolTypeOption)
+		if serviceProtocolSpecFlag && ok {
+			if serviceProtocolOpt.GetProtocolName() != unified_idl_extend.ProtocolType_DUBBO.String() || serviceProtocolOpt == nil {
+				// skip the service which is not dubbo protocol or does not have a service option
+				continue
+			}
+		}
 		serviceMethods := make([]*Method, 0)
+		skipMethodFlag := false
 		for _, method := range service.Methods {
 			if method.Desc.IsStreamingClient() || method.Desc.IsStreamingServer() {
 				return nil, ErrStreamMethod
@@ -87,7 +90,25 @@ func ProcessProtoFile(g *protogen.GeneratedFile, file *protogen.File) (*Dubbogo,
 				ReturnType:  g.QualifiedGoIdent(method.Output.GoIdent),
 			}
 
+			methodProtocolOpt, ok := proto.GetExtension(method.Desc.Options(), unified_idl_extend.E_MethodProtocols).(*unified_idl_extend.MethodProtocolTypeOption)
+			if methodProtocolSpecFlag && ok {
+				flagDubboProtocol := false
+				for _, protoName := range methodProtocolOpt.GetProtocolNames() {
+					if protoName == unified_idl_extend.ProtocolType_DUBBO.String() {
+						flagDubboProtocol = true
+						break
+					}
+				}
+				if !flagDubboProtocol || methodProtocolOpt == nil {
+					// skip the method which is not dubbo protocol or does not have a method option
+					skipMethodFlag = true
+					continue
+				}
+			}
+			skipMethodFlag = false
+
 			methodOpt, ok := proto.GetExtension(method.Desc.Options(), unified_idl_extend.E_MethodExtend).(*unified_idl_extend.Hessian2MethodOptions)
+
 			invokeName := util.ToLower(method.GoName)
 			if ok && methodOpt != nil {
 				invokeName = methodOpt.MethodName
@@ -116,8 +137,12 @@ func ProcessProtoFile(g *protogen.GeneratedFile, file *protogen.File) (*Dubbogo,
 				goType, _ := util.FieldGoType(g, method.Output.Fields[0])
 				m.ReturnType = goType
 			}
-
-			serviceMethods = append(serviceMethods, m)
+			if !skipMethodFlag {
+				serviceMethods = append(serviceMethods, m)
+			}
+		}
+		if len(serviceMethods) == 0 {
+			continue
 		}
 
 		serviceOpt, ok := proto.GetExtension(service.Desc.Options(), unified_idl_extend.E_ServiceExtend).(*unified_idl_extend.Hessian2ServiceOptions)
@@ -132,5 +157,9 @@ func ProcessProtoFile(g *protogen.GeneratedFile, file *protogen.File) (*Dubbogo,
 		})
 	}
 
+	if len(dubboGo.Services) == 0 {
+		return nil, fmt.Errorf("no service found in %s", dubboGo.Source)
+	}
+
 	return dubboGo, nil
 }

main.go

@@ -18,25 +18,25 @@
 package main
 
 import (
+	"flag"
 	"fmt"
 	"os"
-)
 
-import (
-	"google.golang.org/protobuf/compiler/protogen"
-	"google.golang.org/protobuf/types/pluginpb"
-)
-
-import (
 	"github.com/dubbogo/protoc-gen-go-dubbo/generator"
 	"github.com/dubbogo/protoc-gen-go-dubbo/internal/version"
+	"google.golang.org/protobuf/compiler/protogen"
+	"google.golang.org/protobuf/types/pluginpb"
 )
 
 const (
 	usage = "Flags:\n  -h, --help\tPrint this help and exit.\n      --version\tPrint the version and exit."
 )
 
 func main() {
+
+	var flags flag.FlagSet
+	methodProtocolSpecFlag := flags.Bool("in_file_method_protocol_spec", false, "enable the in-file method transport protocol option")
+	serviceProtocolSpecFlag := flags.Bool("in_file_service_protocol_spec", false, "enable the in-file service transport protocol option")
 	if len(os.Args) == 2 && os.Args[1] == "--version" {
 		fmt.Fprintln(os.Stdout, version.Version)
 		os.Exit(0)
@@ -50,14 +50,20 @@ func main() {
 		os.Exit(1)
 	}
 
-	protogen.Options{}.Run(func(gen *protogen.Plugin) error {
+	flags.Init("protoc-gen-go-dubbo", flag.ContinueOnError)
+
+	protogen.Options{
+		ParamFunc: flags.Set,
+	}.Run(func(gen *protogen.Plugin) error {
 		gen.SupportedFeatures = uint64(pluginpb.CodeGeneratorResponse_FEATURE_PROTO3_OPTIONAL)
 		for _, file := range gen.Files {
 			if file.Generate {
 				filename := file.GeneratedFilenamePrefix + ".dubbo.go"
 				g := gen.NewGeneratedFile(filename, file.GoImportPath)
-
-				dubboGo, err := generator.ProcessProtoFile(g, file)
+				if *methodProtocolSpecFlag && *serviceProtocolSpecFlag {
+					return fmt.Errorf("in_file_method_protocol_spec and in_file_service_protocol_spec can't be true at the same time")
+				}
+				dubboGo, err := generator.ProcessProtoFile(g, file, *methodProtocolSpecFlag, *serviceProtocolSpecFlag)
 				if err != nil {
 					return err
 				}