Method Test_RLSDefaultTargetPicksMetric

balancer/rls/picker_test.go:256–290

Test_RLSDefaultTargetPicksMetric tests the default target picks metric. It configures an RLS Balancer which specifies to route to the default target in the RLS Configuration, and makes an RPC on a Channel containing this RLS Balancer. This test then asserts a default target picks metric is emitted,

(t *testing.T)

// Balancer. This test then asserts a default target picks metric is emitted,
// and target pick or failed pick metric is not emitted.
func (s) Test_RLSDefaultTargetPicksMetric(t *testing.T) {
	// Start an RLS server and set the throttler to always throttle requests.
	rlsServer, _ := rlstest.SetupFakeRLSServer(t, nil)
	overrideAdaptiveThrottler(t, alwaysThrottlingThrottler())

	// Build RLS service config with a default target.
	rlsConfig := buildBasicRLSConfigWithChildPolicy(t, t.Name(), rlsServer.Address)
	defBackendCh, defBackendAddress := startBackend(t)
	rlsConfig.RouteLookupConfig.DefaultTarget = defBackendAddress

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

	tmr := stats.NewTestMetricsRecorder()
	cc, err := grpc.NewClient(r.Scheme()+":///", grpc.WithResolvers(r), grpc.WithTransportCredentials(insecure.NewCredentials()), grpc.WithStatsHandler(tmr))
	if err != nil {
		t.Fatalf("grpc.NewClient() failed: %v", err)
	}
	defer cc.Close()

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

	if got, _ := tmr.Metric("grpc.lb.rls.default_target_picks"); got != 1 {
		t.Fatalf("Unexpected data for metric %v, got: %v, want: %v", "grpc.lb.rls.default_target_picks", got, 1)
	}
	if _, ok := tmr.Metric("grpc.lb.rls.target_picks"); ok {
		t.Fatalf("Data is present for metric %v", "grpc.lb.rls.target_picks")
	}
	if _, ok := tmr.Metric("grpc.lb.rls.failed_picks"); ok {
		t.Fatalf("Data is present for metric %v", "grpc.lb.rls.failed_picks")
	}
}

// Test_RLSTargetPicksMetric tests the target picks metric. It configures an RLS
// Balancer which specifies to route to a target through a RouteLookupResponse,