1/* 2 * 3 * Copyright 2020 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 stub implements a balancer for testing purposes. 20package stub 21 22import "google.golang.org/grpc/balancer" 23 24// BalancerFuncs contains all balancer.Balancer functions with a preceding 25// *BalancerData parameter for passing additional instance information. Any 26// nil functions will never be called. 27type BalancerFuncs struct { 28 // Init is called after ClientConn and BuildOptions are set in 29 // BalancerData. It may be used to initialize BalancerData.Data. 30 Init func(*BalancerData) 31 32 UpdateClientConnState func(*BalancerData, balancer.ClientConnState) error 33 ResolverError func(*BalancerData, error) 34 UpdateSubConnState func(*BalancerData, balancer.SubConn, balancer.SubConnState) 35 Close func(*BalancerData) 36 ExitIdle func(*BalancerData) 37} 38 39// BalancerData contains data relevant to a stub balancer. 40type BalancerData struct { 41 // ClientConn is set by the builder. 42 ClientConn balancer.ClientConn 43 // BuildOptions is set by the builder. 44 BuildOptions balancer.BuildOptions 45 // Data may be used to store arbitrary user data. 46 Data interface{} 47} 48 49type bal struct { 50 bf BalancerFuncs 51 bd *BalancerData 52} 53 54func (b *bal) UpdateClientConnState(c balancer.ClientConnState) error { 55 if b.bf.UpdateClientConnState != nil { 56 return b.bf.UpdateClientConnState(b.bd, c) 57 } 58 return nil 59} 60 61func (b *bal) ResolverError(e error) { 62 if b.bf.ResolverError != nil { 63 b.bf.ResolverError(b.bd, e) 64 } 65} 66 67func (b *bal) UpdateSubConnState(sc balancer.SubConn, scs balancer.SubConnState) { 68 if b.bf.UpdateSubConnState != nil { 69 b.bf.UpdateSubConnState(b.bd, sc, scs) 70 } 71} 72 73func (b *bal) Close() { 74 if b.bf.Close != nil { 75 b.bf.Close(b.bd) 76 } 77} 78 79func (b *bal) ExitIdle() { 80 if b.bf.ExitIdle != nil { 81 b.bf.ExitIdle(b.bd) 82 } 83} 84 85type bb struct { 86 name string 87 bf BalancerFuncs 88} 89 90func (bb bb) Build(cc balancer.ClientConn, opts balancer.BuildOptions) balancer.Balancer { 91 b := &bal{bf: bb.bf, bd: &BalancerData{ClientConn: cc, BuildOptions: opts}} 92 if b.bf.Init != nil { 93 b.bf.Init(b.bd) 94 } 95 return b 96} 97 98func (bb bb) Name() string { return bb.name } 99 100// Register registers a stub balancer builder which will call the provided 101// functions. The name used should be unique. 102func Register(name string, bf BalancerFuncs) { 103 balancer.Register(bb{name: name, bf: bf}) 104} 105