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client: add a test for NewSubConn / StateListener / cc.Close racing (#…
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dfawley authored Oct 4, 2023
1 parent 318c717 commit 696faa9
Showing 1 changed file with 81 additions and 0 deletions.
81 changes: 81 additions & 0 deletions balancer_conn_wrappers_test.go
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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 grpc

import (
"fmt"
"strings"
"sync"
"testing"

"google.golang.org/grpc/balancer"
"google.golang.org/grpc/credentials/insecure"
"google.golang.org/grpc/internal/balancer/stub"
"google.golang.org/grpc/internal/grpcsync"
)

// TestBalancer_StateListenerBeforeConnect tries to stimulate a race between
// NewSubConn and ClientConn.Close. In no cases should the SubConn's
// StateListener be invoked, because Connect was never called.
func (s) TestBalancer_StateListenerBeforeConnect(t *testing.T) {
// started is fired after cc is set so cc can be used in the balancer.
started := grpcsync.NewEvent()
var cc *ClientConn

wg := sync.WaitGroup{}
wg.Add(2)

// Create a balancer that calls NewSubConn and cc.Close at approximately the
// same time.
bf := stub.BalancerFuncs{
UpdateClientConnState: func(bd *stub.BalancerData, ccs balancer.ClientConnState) error {
go func() {
// Wait for cc to be valid after the channel is created.
<-started.Done()
// In a goroutine, create the subconn.
go func() {
_, err := bd.ClientConn.NewSubConn(ccs.ResolverState.Addresses, balancer.NewSubConnOptions{
StateListener: func(scs balancer.SubConnState) {
t.Error("Unexpected call to StateListener with:", scs)
},
})
if err != nil && !strings.Contains(err.Error(), "connection is closing") && !strings.Contains(err.Error(), "is deleted") && !strings.Contains(err.Error(), "is closed or idle") {
t.Error("Unexpected error creating subconn:", err)
}
wg.Done()
}()
// At approximately the same time, close the channel.
cc.Close()
wg.Done()
}()
return nil
},
}
stub.Register(t.Name(), bf)
svcCfg := fmt.Sprintf(`{ "loadBalancingConfig": [{%q: {}}] }`, t.Name())

cc, err := Dial("fake", WithTransportCredentials(insecure.NewCredentials()), WithDefaultServiceConfig(svcCfg))
if err != nil {
t.Fatal("Error dialing:", err)
}
started.Fire()

// Wait for the LB policy to call NewSubConn and cc.Close.
wg.Wait()
}

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