terraformDummyRepo2/vendor/google.golang.org/grpc/balancer/base/base.go

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/*
*
* Copyright 2017 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
// Package base defines a balancer base that can be used to build balancers with
// different picking algorithms.
//
// The base balancer creates a new SubConn for each resolved address. The
// provided picker will only be notified about READY SubConns.
//
// This package is the base of round_robin balancer, its purpose is to be used
// to build round_robin like balancers with complex picking algorithms.
// Balancers with more complicated logic should try to implement a balancer
// builder from scratch.
//
// All APIs in this package are experimental.
package base
import (
"google.golang.org/grpc/balancer"
"google.golang.org/grpc/resolver"
)
// PickerBuilder creates balancer.Picker.
type PickerBuilder interface {
// Build takes a slice of ready SubConns, and returns a picker that will be
// used by gRPC to pick a SubConn.
Build(readySCs map[resolver.Address]balancer.SubConn) balancer.Picker
}
// V2PickerBuilder creates balancer.V2Picker.
type V2PickerBuilder interface {
// Build returns a picker that will be used by gRPC to pick a SubConn.
Build(info PickerBuildInfo) balancer.V2Picker
}
// PickerBuildInfo contains information needed by the picker builder to
// construct a picker.
type PickerBuildInfo struct {
// ReadySCs is a map from all ready SubConns to the Addresses used to
// create them.
ReadySCs map[balancer.SubConn]SubConnInfo
}
// SubConnInfo contains information about a SubConn created by the base
// balancer.
type SubConnInfo struct {
Address resolver.Address // the address used to create this SubConn
}
// NewBalancerBuilder returns a balancer builder. The balancers
// built by this builder will use the picker builder to build pickers.
func NewBalancerBuilder(name string, pb PickerBuilder) balancer.Builder {
return NewBalancerBuilderWithConfig(name, pb, Config{})
}
// Config contains the config info about the base balancer builder.
type Config struct {
// HealthCheck indicates whether health checking should be enabled for this specific balancer.
HealthCheck bool
}
// NewBalancerBuilderWithConfig returns a base balancer builder configured by the provided config.
func NewBalancerBuilderWithConfig(name string, pb PickerBuilder, config Config) balancer.Builder {
return &baseBuilder{
name: name,
pickerBuilder: pb,
config: config,
}
}
// NewBalancerBuilderV2 returns a base balancer builder configured by the provided config.
func NewBalancerBuilderV2(name string, pb V2PickerBuilder, config Config) balancer.Builder {
return &baseBuilder{
name: name,
v2PickerBuilder: pb,
config: config,
}
}