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 19 package grpcutil
20 21 import (
22 "context"
23 24 "google.golang.org/grpc/metadata"
25 )
26 27 type mdExtraKey struct{}
28 29 // WithExtraMetadata creates a new context with incoming md attached.
30 func 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.
37 func ExtraMetadata(ctx context.Context) (md metadata.MD, ok bool) {
38 md, ok = ctx.Value(mdExtraKey{}).(metadata.MD)
39 return
40 }
41