dubbo.apache.org/dubbo-go/v3@v3.1.1/xds/utils/metadata/metadata.go (about)

     1  /*
     2   * Licensed to the Apache Software Foundation (ASF) under one or more
     3   * contributor license agreements.  See the NOTICE file distributed with
     4   * this work for additional information regarding copyright ownership.
     5   * The ASF licenses this file to You under the Apache License, Version 2.0
     6   * (the "License"); you may not use this file except in compliance with
     7   * the License.  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   *
    20   * Copyright 2020 gRPC authors.
    21   *
    22   */
    23  
    24  package metadata
    25  
    26  import (
    27  	"context"
    28  )
    29  
    30  import (
    31  	"google.golang.org/grpc/metadata"
    32  )
    33  
    34  type mdExtraKey struct{}
    35  
    36  // WithExtraMetadata creates a new context with incoming md attached.
    37  func WithExtraMetadata(ctx context.Context, md metadata.MD) context.Context {
    38  	return context.WithValue(ctx, mdExtraKey{}, md)
    39  }
    40  
    41  // ExtraMetadata returns the incoming metadata in ctx if it exists.  The
    42  // returned MD should not be modified. Writing to it may cause races.
    43  // Modification should be made to copies of the returned MD.
    44  func ExtraMetadata(ctx context.Context) (md metadata.MD, ok bool) {
    45  	md, ok = ctx.Value(mdExtraKey{}).(metadata.MD)
    46  	return
    47  }