An Exercise in dumping the file descriptor of the grpc-go helloworld example

dump_descriptor.go

package main

import (
	"bytes"
	"compress/gzip"
	"io/ioutil"
	"log"

	"github.com/davecgh/go-spew/spew"
	"github.com/golang/protobuf/proto"
	_ "google.golang.org/grpc/examples/helloworld/helloworld"

	"github.com/golang/protobuf/protoc-gen-go/descriptor"
)

func main() {
	c := proto.FileDescriptor("helloworld.proto")
	r, err := gzip.NewReader(bytes.NewReader(c))
	if err != nil {
		log.Fatal(err)
	}
	u, err := ioutil.ReadAll(r)
	if err != nil {
		log.Fatal(err)
	}

	var d descriptor.FileDescriptorProto
	err = proto.Unmarshal(u, &d)
	if err != nil {
		log.Fatal(err)
	}
	spew.Dump(d)
}