Matteo Scandolo | a6a3aee | 2019-11-26 13:30:14 -0700 | [diff] [blame] | 1 | /* |
| 2 | * |
| 3 | * Copyright 2017 gRPC authors. |
| 4 | * |
| 5 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 6 | * you may not use this file except in compliance with the License. |
| 7 | * 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 | // Package base defines a balancer base that can be used to build balancers with |
| 20 | // different picking algorithms. |
| 21 | // |
| 22 | // The base balancer creates a new SubConn for each resolved address. The |
| 23 | // provided picker will only be notified about READY SubConns. |
| 24 | // |
| 25 | // This package is the base of round_robin balancer, its purpose is to be used |
| 26 | // to build round_robin like balancers with complex picking algorithms. |
| 27 | // Balancers with more complicated logic should try to implement a balancer |
| 28 | // builder from scratch. |
| 29 | // |
| 30 | // All APIs in this package are experimental. |
| 31 | package base |
| 32 | |
| 33 | import ( |
| 34 | "google.golang.org/grpc/balancer" |
| 35 | "google.golang.org/grpc/resolver" |
| 36 | ) |
| 37 | |
| 38 | // PickerBuilder creates balancer.Picker. |
| 39 | type PickerBuilder interface { |
| 40 | // Build takes a slice of ready SubConns, and returns a picker that will be |
| 41 | // used by gRPC to pick a SubConn. |
| 42 | Build(readySCs map[resolver.Address]balancer.SubConn) balancer.Picker |
| 43 | } |
| 44 | |
Arjun E K | 57a7fcb | 2020-01-30 06:44:45 +0000 | [diff] [blame^] | 45 | // V2PickerBuilder creates balancer.V2Picker. |
| 46 | type V2PickerBuilder interface { |
| 47 | // Build returns a picker that will be used by gRPC to pick a SubConn. |
| 48 | Build(info PickerBuildInfo) balancer.V2Picker |
| 49 | } |
| 50 | |
| 51 | // PickerBuildInfo contains information needed by the picker builder to |
| 52 | // construct a picker. |
| 53 | type PickerBuildInfo struct { |
| 54 | // ReadySCs is a map from all ready SubConns to the Addresses used to |
| 55 | // create them. |
| 56 | ReadySCs map[balancer.SubConn]SubConnInfo |
| 57 | } |
| 58 | |
| 59 | // SubConnInfo contains information about a SubConn created by the base |
| 60 | // balancer. |
| 61 | type SubConnInfo struct { |
| 62 | Address resolver.Address // the address used to create this SubConn |
| 63 | } |
| 64 | |
Matteo Scandolo | a6a3aee | 2019-11-26 13:30:14 -0700 | [diff] [blame] | 65 | // NewBalancerBuilder returns a balancer builder. The balancers |
| 66 | // built by this builder will use the picker builder to build pickers. |
| 67 | func NewBalancerBuilder(name string, pb PickerBuilder) balancer.Builder { |
| 68 | return NewBalancerBuilderWithConfig(name, pb, Config{}) |
| 69 | } |
| 70 | |
| 71 | // Config contains the config info about the base balancer builder. |
| 72 | type Config struct { |
| 73 | // HealthCheck indicates whether health checking should be enabled for this specific balancer. |
| 74 | HealthCheck bool |
| 75 | } |
| 76 | |
| 77 | // NewBalancerBuilderWithConfig returns a base balancer builder configured by the provided config. |
| 78 | func NewBalancerBuilderWithConfig(name string, pb PickerBuilder, config Config) balancer.Builder { |
| 79 | return &baseBuilder{ |
| 80 | name: name, |
| 81 | pickerBuilder: pb, |
| 82 | config: config, |
| 83 | } |
| 84 | } |
Arjun E K | 57a7fcb | 2020-01-30 06:44:45 +0000 | [diff] [blame^] | 85 | |
| 86 | // NewBalancerBuilderV2 returns a base balancer builder configured by the provided config. |
| 87 | func NewBalancerBuilderV2(name string, pb V2PickerBuilder, config Config) balancer.Builder { |
| 88 | return &baseBuilder{ |
| 89 | name: name, |
| 90 | v2PickerBuilder: pb, |
| 91 | config: config, |
| 92 | } |
| 93 | } |