go.uber.org/yarpc@v1.72.1/peer/randpeer/config.go (about)

     1  // Copyright (c) 2022 Uber Technologies, Inc.
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     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 randpeer
    22  
    23  import (
    24  	"fmt"
    25  	"time"
    26  
    27  	"go.uber.org/yarpc/api/peer"
    28  	"go.uber.org/yarpc/yarpcconfig"
    29  	"go.uber.org/yarpc/yarpcerrors"
    30  )
    31  
    32  // Configuration descripes how to build a random peer list.
    33  type Configuration struct {
    34  	Capacity *int `config:"capacity"`
    35  	FailFast bool `config:"failFast"`
    36  	// DefaultChooseTimeout specifies the deadline to add to Choose calls if not
    37  	// present. This enables calls without deadlines, ie streaming, to choose
    38  	// peers without waiting indefinitely.
    39  	DefaultChooseTimeout *time.Duration `config:"defaultChooseTimeout"`
    40  }
    41  
    42  // Spec returns a configuration specification for the random peer list
    43  // implementation, making it possible to select a random peer with transports
    44  // that use outbound peer list configuration (like HTTP).
    45  //
    46  //  cfg := yarpcconfig.New()
    47  //  cfg.MustRegisterPeerList(random.Spec())
    48  //
    49  // This enables the random peer list:
    50  //
    51  //  outbounds:
    52  //    otherservice:
    53  //      unary:
    54  //        http:
    55  //          url: https://host:port/rpc
    56  //          random:
    57  //            peers:
    58  //              - 127.0.0.1:8080
    59  //              - 127.0.0.1:8081
    60  func Spec() yarpcconfig.PeerListSpec {
    61  	return SpecWithOptions()
    62  }
    63  
    64  // SpecWithOptions accepts additional list constructor options.
    65  func SpecWithOptions(options ...ListOption) yarpcconfig.PeerListSpec {
    66  	return yarpcconfig.PeerListSpec{
    67  		Name: "random",
    68  		BuildPeerList: func(cfg Configuration, t peer.Transport, k *yarpcconfig.Kit) (peer.ChooserList, error) {
    69  			opts := make([]ListOption, 0, len(options)+2)
    70  
    71  			opts = append(opts, options...)
    72  
    73  			if cfg.Capacity != nil {
    74  				if *cfg.Capacity <= 0 {
    75  					return nil, yarpcerrors.Newf(yarpcerrors.CodeInvalidArgument,
    76  						fmt.Sprintf("Capacity must be greater than 0. Got: %d.", *cfg.Capacity))
    77  				}
    78  				opts = append(opts, Capacity(*cfg.Capacity))
    79  			}
    80  
    81  			if cfg.FailFast {
    82  				opts = append(opts, FailFast())
    83  			}
    84  			if cfg.DefaultChooseTimeout != nil {
    85  				opts = append(opts, DefaultChooseTimeout(*cfg.DefaultChooseTimeout))
    86  			}
    87  			return New(t, opts...), nil
    88  		},
    89  	}
    90  }