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 19package xdsrouting 20 21import ( 22 "google.golang.org/grpc/balancer" 23 "google.golang.org/grpc/codes" 24 "google.golang.org/grpc/status" 25 "google.golang.org/grpc/xds/internal" 26) 27 28// pickerGroup contains a list of route matchers and their corresponding 29// pickers. For each pick, the first matched picker is used. If the picker isn't 30// ready, the pick will be queued. 31type pickerGroup struct { 32 routes []route 33 pickers map[string]balancer.Picker 34} 35 36func newPickerGroup(routes []route, idToPickerState map[internal.LocalityID]*subBalancerState) *pickerGroup { 37 pickers := make(map[string]balancer.Picker) 38 for id, st := range idToPickerState { 39 pickers[getNameFromLocality(id)] = st.state.Picker 40 } 41 return &pickerGroup{ 42 routes: routes, 43 pickers: pickers, 44 } 45} 46 47var errNoMatchedRouteFound = status.Errorf(codes.Unavailable, "no matched route was found") 48 49func (pg *pickerGroup) Pick(info balancer.PickInfo) (balancer.PickResult, error) { 50 for _, rt := range pg.routes { 51 if rt.m.match(info) { 52 // action from route is the ID for the sub-balancer to use. 53 p, ok := pg.pickers[rt.action] 54 if !ok { 55 return balancer.PickResult{}, balancer.ErrNoSubConnAvailable 56 } 57 return p.Pick(info) 58 } 59 } 60 return balancer.PickResult{}, errNoMatchedRouteFound 61} 62