forked from grpc/grpc-go
/
routing_picker.go
60 lines (54 loc) · 1.75 KB
/
routing_picker.go
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/*
*
* Copyright 2020 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 xdsrouting
import (
"google.golang.org/grpc/balancer"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/status"
)
// pickerGroup contains a list of route matchers and their corresponding
// pickers. For each pick, the first matched picker is used. If the picker isn't
// ready, the pick will be queued.
type pickerGroup struct {
routes []route
pickers map[string]balancer.Picker
}
func newPickerGroup(routes []route, idToPickerState map[string]*subBalancerState) *pickerGroup {
pickers := make(map[string]balancer.Picker)
for id, st := range idToPickerState {
pickers[id] = st.state.Picker
}
return &pickerGroup{
routes: routes,
pickers: pickers,
}
}
var errNoMatchedRouteFound = status.Errorf(codes.Unavailable, "no matched route was found")
func (pg *pickerGroup) Pick(info balancer.PickInfo) (balancer.PickResult, error) {
for _, rt := range pg.routes {
if rt.m.match(info) {
// action from route is the ID for the sub-balancer to use.
p, ok := pg.pickers[rt.action]
if !ok {
return balancer.PickResult{}, balancer.ErrNoSubConnAvailable
}
return p.Pick(info)
}
}
return balancer.PickResult{}, errNoMatchedRouteFound
}