Method TestEnterIdleDuringBalancerNewSubConn

resolver_balancer_ext_test.go:261–306

TestEnterIdleDuringBalancerNewSubConn tests calling NewSubConn at the same time as the balancer being closed while the channel enters idle mode.

(t *testing.T)

// TestEnterIdleDuringBalancerNewSubConn tests calling NewSubConn at the same
// time as the balancer being closed while the channel enters idle mode.
func (s) TestEnterIdleDuringBalancerNewSubConn(t *testing.T) {
	channelz.TurnOn()
	defer internal.ChannelzTurnOffForTesting()
	enterIdle := internal.EnterIdleModeForTesting.(func(*grpc.ClientConn))
	name := strings.ReplaceAll(strings.ToLower(t.Name()), "/", "")

	// Create a balancer that calls NewSubConn once asynchronously, attempting
	// to create a subchannel after going idle.
	bf := stub.BalancerFuncs{
		UpdateClientConnState: func(bd *stub.BalancerData, _ balancer.ClientConnState) error {
			go func() {
				bd.ClientConn.NewSubConn([]resolver.Address{{Addr: "test"}}, balancer.NewSubConnOptions{})
			}()
			return nil
		},
	}
	stub.Register(name, bf)

	rb := manual.NewBuilderWithScheme(name)
	rb.BuildCallback = func(_ resolver.Target, cc resolver.ClientConn, _ resolver.BuildOptions) {
		cc.UpdateState(resolver.State{Addresses: []resolver.Address{{Addr: "test"}}})
	}
	resolver.Register(rb)

	cc, err := grpc.NewClient(
		name+":///",
		grpc.WithTransportCredentials(insecure.NewCredentials()),
		grpc.WithDefaultServiceConfig(`{"loadBalancingConfig": [{"`+name+`":{}}]}`))
	if err != nil {
		t.Fatalf("grpc.NewClient error: %v", err)
	}
	defer cc.Close()

	// Enter/exit idle mode repeatedly.
	for i := 0; i < 2000; i++ {
		enterIdle(cc)
		tcs, _ := channelz.GetTopChannels(0, 0)
		if len(tcs) != 1 {
			t.Fatalf("Found channels: %v; expected 1 entry", tcs)
		}
		if got := tcs[0].SubChans(); len(got) != 0 {
			t.Fatalf("Found subchannels: %v; expected 0 entries", got)
		}
		cc.Connect()
	}
}