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/*
*
* Copyright 2023 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 xds contains various xds interop helpers for usage in interop tests.
package xds
import (
"encoding/json"
"fmt"
"sync"
"google.golang.org/grpc/balancer"
"google.golang.org/grpc/balancer/roundrobin"
"google.golang.org/grpc/internal/pretty"
"google.golang.org/grpc/metadata"
"google.golang.org/grpc/serviceconfig"
)
func init() {
balancer.Register(rpcBehaviorBB{})
}
const name = "test.RpcBehaviorLoadBalancer"
type rpcBehaviorBB struct{}
func (rpcBehaviorBB) Build(cc balancer.ClientConn, bOpts balancer.BuildOptions) balancer.Balancer {
b := &rpcBehaviorLB{
ClientConn: cc,
}
// round_robin child to complete balancer tree with a usable leaf policy and
// have RPCs actually work.
builder := balancer.Get(roundrobin.Name)
if builder == nil {
// Shouldn't happen, defensive programming. Registered from import of
// roundrobin package.
return nil
}
rr := builder.Build(b, bOpts)
if rr == nil {
// Shouldn't happen, defensive programming.
return nil
}
b.Balancer = rr
return b
}
func (rpcBehaviorBB) ParseConfig(s json.RawMessage) (serviceconfig.LoadBalancingConfig, error) {
lbCfg := &lbConfig{}
if err := json.Unmarshal(s, lbCfg); err != nil {
return nil, fmt.Errorf("rpc-behavior-lb: unable to marshal lbConfig: %s, error: %v", string(s), err)
}
return lbCfg, nil
}
func (rpcBehaviorBB) Name() string {
return name
}
type lbConfig struct {
serviceconfig.LoadBalancingConfig `json:"-"`
RPCBehavior string `json:"rpcBehavior,omitempty"`
}
// rpcBehaviorLB is a load balancer that wraps a round robin balancer and
// appends the rpc-behavior metadata field to any metadata in pick results based
// on what is specified in configuration.
type rpcBehaviorLB struct {
// embed a ClientConn to wrap only UpdateState() operation
balancer.ClientConn
// embed a Balancer to wrap only UpdateClientConnState() operation
balancer.Balancer
mu sync.Mutex
cfg *lbConfig
}
func (b *rpcBehaviorLB) UpdateClientConnState(s balancer.ClientConnState) error {
lbCfg, ok := s.BalancerConfig.(*lbConfig)
if !ok {
return fmt.Errorf("test.RpcBehaviorLoadBalancer:received config with unexpected type %T: %s", s.BalancerConfig, pretty.ToJSON(s.BalancerConfig))
}
b.mu.Lock()
b.cfg = lbCfg
b.mu.Unlock()
return b.Balancer.UpdateClientConnState(balancer.ClientConnState{
ResolverState: s.ResolverState,
})
}
func (b *rpcBehaviorLB) UpdateState(state balancer.State) {
b.mu.Lock()
rpcBehavior := b.cfg.RPCBehavior
b.mu.Unlock()
b.ClientConn.UpdateState(balancer.State{
ConnectivityState: state.ConnectivityState,
Picker: newRPCBehaviorPicker(state.Picker, rpcBehavior),
})
}
// rpcBehaviorPicker wraps a picker and adds the rpc-behavior metadata field
// into the child pick result's metadata.
type rpcBehaviorPicker struct {
childPicker balancer.Picker
rpcBehavior string
}
// Pick appends the rpc-behavior metadata entry to the pick result of the child.
func (p *rpcBehaviorPicker) Pick(info balancer.PickInfo) (balancer.PickResult, error) {
pr, err := p.childPicker.Pick(info)
if err != nil {
return balancer.PickResult{}, err
}
pr.Metadata = metadata.Join(pr.Metadata, metadata.Pairs("rpc-behavior", p.rpcBehavior))
return pr, nil
}
func newRPCBehaviorPicker(childPicker balancer.Picker, rpcBehavior string) *rpcBehaviorPicker {
return &rpcBehaviorPicker{
childPicker: childPicker,
rpcBehavior: rpcBehavior,
}
}
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