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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 clustermanager implements the cluster manager LB policy for xds.
package clustermanager
import (
"encoding/json"
"fmt"
"google.golang.org/grpc/balancer"
"google.golang.org/grpc/grpclog"
"google.golang.org/grpc/internal/balancergroup"
internalgrpclog "google.golang.org/grpc/internal/grpclog"
"google.golang.org/grpc/internal/hierarchy"
"google.golang.org/grpc/internal/pretty"
"google.golang.org/grpc/resolver"
"google.golang.org/grpc/serviceconfig"
)
const balancerName = "xds_cluster_manager_experimental"
func init() {
balancer.Register(bb{})
}
type bb struct{}
func (bb) Build(cc balancer.ClientConn, opts balancer.BuildOptions) balancer.Balancer {
b := &bal{}
b.logger = prefixLogger(b)
b.stateAggregator = newBalancerStateAggregator(cc, b.logger)
b.stateAggregator.start()
b.bg = balancergroup.New(cc, opts, b.stateAggregator, b.logger)
b.bg.Start()
b.logger.Infof("Created")
return b
}
func (bb) Name() string {
return balancerName
}
func (bb) ParseConfig(c json.RawMessage) (serviceconfig.LoadBalancingConfig, error) {
return parseConfig(c)
}
type bal struct {
logger *internalgrpclog.PrefixLogger
// TODO: make this package not dependent on xds specific code. Same as for
// weighted target balancer.
bg *balancergroup.BalancerGroup
stateAggregator *balancerStateAggregator
children map[string]childConfig
}
func (b *bal) updateChildren(s balancer.ClientConnState, newConfig *lbConfig) {
update := false
addressesSplit := hierarchy.Group(s.ResolverState.Addresses)
// Remove sub-pickers and sub-balancers that are not in the new cluster list.
for name := range b.children {
if _, ok := newConfig.Children[name]; !ok {
b.stateAggregator.remove(name)
b.bg.Remove(name)
update = true
}
}
// For sub-balancers in the new cluster list,
// - add to balancer group if it's new,
// - forward the address/balancer config update.
for name, newT := range newConfig.Children {
if _, ok := b.children[name]; !ok {
// If this is a new sub-balancer, add it to the picker map.
b.stateAggregator.add(name)
// Then add to the balancer group.
b.bg.Add(name, balancer.Get(newT.ChildPolicy.Name))
} else {
// Already present, check for type change and if so send down a new builder.
if newT.ChildPolicy.Name != b.children[name].ChildPolicy.Name {
b.bg.UpdateBuilder(name, balancer.Get(newT.ChildPolicy.Name))
}
}
// TODO: handle error? How to aggregate errors and return?
_ = b.bg.UpdateClientConnState(name, balancer.ClientConnState{
ResolverState: resolver.State{
Addresses: addressesSplit[name],
ServiceConfig: s.ResolverState.ServiceConfig,
Attributes: s.ResolverState.Attributes,
},
BalancerConfig: newT.ChildPolicy.Config,
})
}
b.children = newConfig.Children
if update {
b.stateAggregator.buildAndUpdate()
}
}
func (b *bal) UpdateClientConnState(s balancer.ClientConnState) error {
newConfig, ok := s.BalancerConfig.(*lbConfig)
if !ok {
return fmt.Errorf("unexpected balancer config with type: %T", s.BalancerConfig)
}
b.logger.Infof("update with config %+v, resolver state %+v", pretty.ToJSON(s.BalancerConfig), s.ResolverState)
b.stateAggregator.pauseStateUpdates()
defer b.stateAggregator.resumeStateUpdates()
b.updateChildren(s, newConfig)
return nil
}
func (b *bal) ResolverError(err error) {
b.bg.ResolverError(err)
}
func (b *bal) UpdateSubConnState(sc balancer.SubConn, state balancer.SubConnState) {
b.bg.UpdateSubConnState(sc, state)
}
func (b *bal) Close() {
b.stateAggregator.close()
b.bg.Close()
b.logger.Infof("Shutdown")
}
func (b *bal) ExitIdle() {
b.bg.ExitIdle()
}
const prefix = "[xds-cluster-manager-lb %p] "
var logger = grpclog.Component("xds")
func prefixLogger(p *bal) *internalgrpclog.PrefixLogger {
return internalgrpclog.NewPrefixLogger(logger, fmt.Sprintf(prefix, p))
}
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