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