go.uber.org/yarpc@v1.72.1/internal/inboundcall/metadata.go (about)

     1  // Copyright (c) 2022 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
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     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package inboundcall
    22  
    23  import (
    24  	"context"
    25  
    26  	"go.uber.org/yarpc/api/transport"
    27  )
    28  
    29  // Metadata holds metadata for an incoming request. This includes metadata
    30  // about the inbound request as well as response metadata.
    31  //
    32  // This drives the behavior of yarpc.Call and encoding.Call.
    33  type Metadata interface {
    34  	WriteResponseHeader(k, v string) error
    35  	Caller() string
    36  	Service() string
    37  	Transport() string
    38  	Procedure() string
    39  	Encoding() transport.Encoding
    40  	Headers() transport.Headers
    41  	ShardKey() string
    42  	RoutingKey() string
    43  	RoutingDelegate() string
    44  	CallerProcedure() string
    45  }
    46  
    47  type metadataKey struct{} // context key for Metadata
    48  
    49  // WithMetadata places the provided metadata on the context.
    50  func WithMetadata(ctx context.Context, md Metadata) context.Context {
    51  	return context.WithValue(ctx, metadataKey{}, md)
    52  }
    53  
    54  // GetMetadata retrieves inbound call metadata from a context.
    55  func GetMetadata(ctx context.Context) (Metadata, bool) {
    56  	md, ok := ctx.Value(metadataKey{}).(Metadata)
    57  	return md, ok
    58  }