Method TestConfigUpdate_ControlChannelServiceConfig

balancer/rls/balancer_test.go:196–251

TestConfigUpdate_ControlChannelServiceConfig tests the scenario where RLS LB policy's configuration specifies the service config for the control channel via the `routeLookupChannelServiceConfig` field. This test verifies that the provided service config is applied for the control channel.

(t *testing.T)

// via the `routeLookupChannelServiceConfig` field. This test verifies that the
// provided service config is applied for the control channel.
func (s) TestConfigUpdate_ControlChannelServiceConfig(t *testing.T) {
	// Start an RLS server and set the throttler to never throttle requests.
	rlsServer, rlsReqCh := rlstest.SetupFakeRLSServer(t, nil)
	overrideAdaptiveThrottler(t, neverThrottlingThrottler())

	// Register a balancer to be used for the control channel, and set up a
	// callback to get notified when the balancer receives a clientConn updates.
	ccUpdateCh := testutils.NewChannel()
	bf := &e2e.BalancerFuncs{
		UpdateClientConnState: func(cfg *e2e.RLSChildPolicyConfig) error {
			if cfg.Backend != rlsServer.Address {
				return fmt.Errorf("control channel LB policy received config with backend %q, want %q", cfg.Backend, rlsServer.Address)
			}
			ccUpdateCh.Replace(nil)
			return nil
		},
	}
	controlChannelPolicyName := "test-control-channel-" + t.Name()
	e2e.RegisterRLSChildPolicy(controlChannelPolicyName, bf)
	t.Logf("Registered child policy with name %q", controlChannelPolicyName)

	// Build RLS service config and set the `routeLookupChannelServiceConfig`
	// field to a service config which uses the above balancer.
	rlsConfig := buildBasicRLSConfigWithChildPolicy(t, t.Name(), rlsServer.Address)
	rlsConfig.RouteLookupChannelServiceConfig = fmt.Sprintf(`{"loadBalancingConfig" : [{%q: {"backend": %q} }]}`, controlChannelPolicyName, rlsServer.Address)

	// Start a test backend, and set up the fake RLS server to return this as a
	// target in the RLS response.
	backendCh, backendAddress := startBackend(t)
	rlsServer.SetResponseCallback(func(_ context.Context, _ *rlspb.RouteLookupRequest) *rlstest.RouteLookupResponse {
		return &rlstest.RouteLookupResponse{Resp: &rlspb.RouteLookupResponse{Targets: []string{backendAddress}}}
	})

	// Register a manual resolver and push the RLS service config through it.
	r := startManualResolverWithConfig(t, rlsConfig)

	cc, err := grpc.NewClient(r.Scheme()+":///rls.test.example.com", grpc.WithResolvers(r), grpc.WithTransportCredentials(insecure.NewCredentials()))
	if err != nil {
		t.Fatalf("Failed to create gRPC client: %v", err)
	}
	defer cc.Close()

	// Make an RPC and ensure it gets routed to the test backend.
	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
	defer cancel()
	makeTestRPCAndExpectItToReachBackend(ctx, t, cc, backendCh)

	// Make sure an RLS request is sent out.
	verifyRLSRequest(t, rlsReqCh, true)

	// Verify that the control channel is using the LB policy we injected via the
	// routeLookupChannelServiceConfig field.
	if _, err := ccUpdateCh.Receive(ctx); err != nil {
		t.Fatalf("timeout when waiting for control channel LB policy to receive a clientConn update")
	}
}

// TestConfigUpdate_DefaultTarget tests the scenario where a config update