proto: add functionality to marshal protobuf binary from file descriptor

Part of cockroachdb#47534

Cockroachdb cannot currently marshal a protobuf binary into JSON based on a provided FileDescriptor.

The newest version of the `google.golang.org/protobuf` package allows for this functionality. gogo/protobuf does not.

Since cockroachdb uses gogo/protobuf for its better performance, I imported `google.golang.org/protobuf` under an alias.

Using that libary, I created `NewJSONMessageFromFileDescriptorn` to take a protobuf binary and a FileDescriptorand return JSON.

To handle linting errors, temporary wrapper functions `TODOMarshal` and `TODOUnmarshal`; these will need to be renamed if this workaround is acceptable

Release note: none

pkg/BUILD.bazel

@@ -1987,6 +1987,7 @@ GO_TARGETS = [
     "//pkg/sql/plpgsql:plpgsql",
     "//pkg/sql/privilege:privilege",
     "//pkg/sql/privilege:privilege_test",
+    "//pkg/sql/protoreflect/gprototest:gprototest",
     "//pkg/sql/protoreflect/test:test",
     "//pkg/sql/protoreflect:protoreflect",
     "//pkg/sql/protoreflect:protoreflect_test",

pkg/gen/protobuf.bzl

@@ -70,6 +70,7 @@ PROTOBUF_SRCS = [
     "//pkg/sql/inverted:inverted_go_proto",
     "//pkg/sql/lex:lex_go_proto",
     "//pkg/sql/pgwire/pgerror:pgerror_go_proto",
+    "//pkg/sql/protoreflect/gprototest:gprototest_go_proto",
     "//pkg/sql/protoreflect/test:protoreflecttest_go_proto",
     "//pkg/sql/rowenc/rowencpb:rowencpb_go_proto",
     "//pkg/sql/schemachanger/scpb:scpb_go_proto",

pkg/sql/protoreflect/BUILD.bazel

@@ -16,6 +16,10 @@ go_library(
         "@com_github_cockroachdb_errors//:errors",
         "@com_github_gogo_protobuf//jsonpb",
         "@com_github_gogo_protobuf//proto",
+        "@org_golang_google_protobuf//encoding/protojson",
+        "@org_golang_google_protobuf//reflect/protodesc",
+        "@org_golang_google_protobuf//reflect/protoreflect",
+        "@org_golang_google_protobuf//types/dynamicpb",
     ],
 )
 
@@ -33,6 +37,7 @@ go_test(
         "//pkg/security/securitytest",
         "//pkg/sql/catalog/catenumpb",
         "//pkg/sql/catalog/descpb",
+        "//pkg/sql/protoreflect/gprototest",
         "//pkg/sql/protoreflect/test",
         "//pkg/sql/types",
         "//pkg/util/json",

pkg/sql/protoreflect/gprototest/BUILD.bazel

@@ -0,0 +1,26 @@
+load("@rules_proto//proto:defs.bzl", "proto_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library")
+
+proto_library(
+    name = "gprototest_proto",
+    srcs = ["gprototest.proto"],
+    strip_import_prefix = "/pkg",
+    visibility = ["//visibility:public"],
+)
+
+go_proto_library(
+    name = "gprototest_go_proto",
+    compilers = ["@io_bazel_rules_go//proto:go_proto"],  #keep
+    importpath = "github.com/cockroachdb/cockroach/pkg/sql/protoreflect/gprototest",
+    proto = ":gprototest_proto",
+    visibility = ["//visibility:public"],
+)
+
+go_library(
+    name = "gprototest",
+    #    srcs = ["wrap.go"],
+    embed = [":gprototest_go_proto"],  # keep
+    importpath = "github.com/cockroachdb/cockroach/pkg/sql/protoreflect/gprototest",
+    visibility = ["//visibility:public"],
+)

pkg/sql/protoreflect/gprototest/gprototest.proto

@@ -0,0 +1,22 @@
+// Copyright 2021 The Cockroach Authors.
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+syntax = "proto3";
+package cockroach.sql.gprototest;
+option go_package = "github.com/cockroachdb/cockroach/pkg/sql/protoreflect/gprototest";
+
+message Inner {
+  string value = 1;
+}
+
+message Outer {
+  string value = 1;
+  Inner inner = 2;
+}

pkg/sql/protoreflect/utils.go

@@ -19,6 +19,10 @@ import (
 	"github.com/cockroachdb/errors"
 	"github.com/gogo/protobuf/jsonpb"
 	"github.com/gogo/protobuf/proto"
+	"google.golang.org/protobuf/encoding/protojson"
+	"google.golang.org/protobuf/reflect/protodesc"
+	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/types/dynamicpb"
 )
 
 var shorthands map[string]protoutil.Message = map[string]protoutil.Message{}
@@ -78,6 +82,42 @@ func NewMessage(name string) (protoutil.Message, error) {
 	return msg, nil
 }
 
+// NewJSONMessageFromFileDescriptor decodes a protobuf message from binary to JSON
+// based on the provided protoreflect.FileDescriptor
+func NewJSONMessageFromFileDescriptor(
+	name string, fd protoreflect.FileDescriptor, data []byte, resolver protodesc.Resolver,
+) (jsonb.JSON, error) {
+	//convert FileDescriptor to FileDescriptorProto
+	fdp := protodesc.ToFileDescriptorProto(fd)
+
+	//create new proto File from FileDescriptorProto
+	f, err := protodesc.NewFile(fdp, resolver)
+	if err != nil {
+		return nil, errors.Wrap(err, "error creating protodesc.NewFile: %w")
+	}
+
+	//get MessageDescriptor from File based on provided name
+	md := f.Messages().ByName(protoreflect.Name(name))
+	if md == nil {
+		return nil, errors.Newf("message descriptor was nil for name %s", name)
+	}
+
+	//Get message to unmarshall protobuf binary from the MessageDescriptor
+	mt := dynamicpb.NewMessageType(md)
+	msg := mt.New().Interface()
+
+	//Unmarshal
+	err = protoutil.TODOUnmarshal(data, msg)
+	if err != nil {
+		return nil, err
+	}
+
+	//Format Protobuf message to JSON string
+	json := protojson.Format(msg)
+
+	return jsonb.ParseJSON(json)
+}
+
 // DecodeMessage decodes protocol message specified as its fully
 // qualified name, and it's marshaled data, into a protoutil.Message.
 func DecodeMessage(name string, data []byte) (protoutil.Message, error) {

pkg/sql/protoreflect/utils_test.go

@@ -20,7 +20,8 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/catalog/catenumpb"
 	"github.com/cockroachdb/cockroach/pkg/sql/catalog/descpb"
 	"github.com/cockroachdb/cockroach/pkg/sql/protoreflect"
-	protoreflecttest "github.com/cockroachdb/cockroach/pkg/sql/protoreflect/test"
+	gprotoreflecttest "github.com/cockroachdb/cockroach/pkg/sql/protoreflect/gprototest"
+	"github.com/cockroachdb/cockroach/pkg/sql/protoreflect/test"
 	"github.com/cockroachdb/cockroach/pkg/sql/types"
 	jsonb "github.com/cockroachdb/cockroach/pkg/util/json"
 	"github.com/cockroachdb/cockroach/pkg/util/leaktest"
@@ -261,3 +262,24 @@ func TestInvalidConversions(t *testing.T) {
 		require.Error(t, err)
 	})
 }
+
+func TestNewMessageFromFileDescriptor(t *testing.T) {
+	msg := "Hello, World"
+	in := gprotoreflecttest.Inner{
+		Value: msg,
+	}
+	fd := gprotoreflecttest.File_sql_protoreflect_gprototest_gprototest_proto
+	bin, err := protoutil.TODOMarshal(&in)
+	require.Nil(t, err)
+
+	t.Run("successfully gets message from FileDescriptor", func(t *testing.T) {
+		out, err := protoreflect.NewJSONMessageFromFileDescriptor("Inner", fd, bin, nil)
+		require.Nil(t, err)
+		require.Equal(t, msg, fetchPath(t, out, "value"))
+	})
+	t.Run("fails if name is  incorrect", func(t *testing.T) {
+		out, err := protoreflect.NewJSONMessageFromFileDescriptor("foo", fd, bin, nil)
+		require.Nil(t, out)
+		require.Error(t, err)
+	})
+}

pkg/util/protoutil/BUILD.bazel

@@ -20,6 +20,7 @@ go_library(
         "@com_github_gogo_protobuf//jsonpb",
         "@com_github_gogo_protobuf//proto",
         "@com_github_grpc_ecosystem_grpc_gateway//runtime:go_default_library",
+        "@org_golang_google_protobuf//proto",
     ],
 )
 

pkg/util/protoutil/marshal.go

@@ -15,6 +15,7 @@ import (
 
 	"github.com/cockroachdb/cockroach/pkg/util/buildutil"
 	"github.com/gogo/protobuf/proto"
+	gproto "google.golang.org/protobuf/proto"
 )
 
 // Message extends the proto.Message interface with the MarshalTo and Size
@@ -74,3 +75,11 @@ func Unmarshal(data []byte, pb Message) error {
 	pb.Reset()
 	return pb.Unmarshal(data)
 }
+
+func TODOMarshal(pb gproto.Message) ([]byte, error) {
+	return gproto.Marshal(pb)
+}
+
+func TODOUnmarshal(data []byte, pb gproto.Message) error {
+	return gproto.Unmarshal(data, pb)
+}