scrubber.go

package main

import (
	"flag"
	"google.golang.org/protobuf/reflect/protoreflect"
	"io/ioutil"
	"log"
	"os"

	"google.golang.org/genproto/googleapis/api/annotations"
	"google.golang.org/genproto/googleapis/longrunning"
	"google.golang.org/protobuf/proto"
	"google.golang.org/protobuf/types/descriptorpb"
)

func main() {
	var filename string
	flag.StringVar(&filename, "f", "", "file descriptor set to scrub")
	flag.Parse()
	if filename == "" {
		flag.Usage()
		os.Exit(1)
	}
	input, err := ioutil.ReadFile(filename)
	if err != nil {
		log.Fatal(err)
	}
	var fileDescriptorSet descriptorpb.FileDescriptorSet
	if err := proto.Unmarshal(input, &fileDescriptorSet); err != nil {
		log.Fatal(err)
	}
	for _, file := range fileDescriptorSet.GetFile() {
		scrubFileImports(file)
		scrubFileOptions(file)
		for _, message := range file.GetMessageType() {
			scrubResourceReferences(message)
		}
		for _, service := range file.GetService() {
			scrubServiceOptions(service)
			for _, method := range service.GetMethod() {
				scrubMethodOptions(method)
			}
		}
	}
	output, err := proto.Marshal(&fileDescriptorSet)
	if err != nil {
		log.Fatal(err)
	}
	if err := ioutil.WriteFile(filename, output, 0o600); err != nil {
		log.Fatal(err)
	}
}

func scrubFileImports(message *descriptorpb.FileDescriptorProto) {
	for i, dep := range message.GetDependency() {
		switch dep {
		case "google/api/client.proto",
			"google/api/resource.proto",
			"google/api/field_behavior.proto":
			message.Dependency = append(message.Dependency[:i], message.Dependency[i+1:]...)
		default:
			continue
		}
	}
}

func scrubFileOptions(file *descriptorpb.FileDescriptorProto) {
	if file.GetOptions() != nil {
		scrubIfExists(file.GetOptions(), annotations.E_ResourceDefinition)
	}
}

func scrubResourceReferences(message *descriptorpb.DescriptorProto) {
	for _, field := range message.GetField() {
		if field.GetOptions() != nil {
			scrubIfExists(field.GetOptions(), annotations.E_Resource)
			scrubIfExists(field.GetOptions(), annotations.E_ResourceReference)
			scrubIfExists(field.GetOptions(), annotations.E_FieldBehavior)
		}
	}
	for _, nestedMessage := range message.NestedType {
		scrubResourceReferences(nestedMessage)
	}
}

func scrubServiceOptions(service *descriptorpb.ServiceDescriptorProto) {
	if service.GetOptions() != nil {
		scrubIfExists(service.GetOptions(), annotations.E_DefaultHost)
	}
}

func scrubMethodOptions(method *descriptorpb.MethodDescriptorProto) {
	if method.GetOptions() != nil {
		scrubIfExists(method.GetOptions(), annotations.E_MethodSignature)
		scrubIfExists(method.GetOptions(), longrunning.E_OperationInfo)
	}
}

func scrubIfExists(msg proto.Message, extensionType protoreflect.ExtensionType) {
	if proto.HasExtension(msg, extensionType) {
		proto.ClearExtension(msg, extensionType)
	}
}

Try running

go mod init scrubber
go mod tidy
go run ...

This should get all of the packages and run correctly