1/*
 2 *
 3 * Copyright 2020 gRPC authors.
 4 *
 5 * Licensed under the Apache License, Version 2.0 (the "License");
 6 * you may not use this file except in compliance with the License.
 7 * You may obtain a copy of the License at
 8 *
 9 *     http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 */
18
19package grpcutil
20
21import (
22	"context"
23
24	"google.golang.org/grpc/metadata"
25)
26
27type mdExtraKey struct{}
28
29// WithExtraMetadata creates a new context with incoming md attached.
30func WithExtraMetadata(ctx context.Context, md metadata.MD) context.Context {
31	return context.WithValue(ctx, mdExtraKey{}, md)
32}
33
34// ExtraMetadata returns the incoming metadata in ctx if it exists.  The
35// returned MD should not be modified. Writing to it may cause races.
36// Modification should be made to copies of the returned MD.
37func ExtraMetadata(ctx context.Context) (md metadata.MD, ok bool) {
38	md, ok = ctx.Value(mdExtraKey{}).(metadata.MD)
39	return
40}