Method Test_RLSFailedPicksMetric

balancer/rls/picker_test.go:342–376

Test_RLSFailedPicksMetric tests the failed picks metric. It configures an RLS Balancer to fail a pick with unavailable, and makes an RPC on a Channel containing this RLS Balancer. This test then asserts a failed picks metric is emitted, and default target pick or target pick metric is not emitted.

(t *testing.T)

// containing this RLS Balancer. This test then asserts a failed picks metric is
// emitted, and default target pick or target pick metric is not emitted.
func (s) Test_RLSFailedPicksMetric(t *testing.T) {
	// Start an RLS server and set the throttler to never throttle requests.
	rlsServer, _ := rlstest.SetupFakeRLSServer(t, nil)
	overrideAdaptiveThrottler(t, neverThrottlingThrottler())

	// Build an RLS config without a default target.
	rlsConfig := buildBasicRLSConfigWithChildPolicy(t, t.Name(), rlsServer.Address)

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

	tmr := stats.NewTestMetricsRecorder()
	// Dial the backend.
	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 expect it to fail with deadline exceeded error. We use a
	// smaller timeout to ensure that the test doesn't run very long.
	ctx, cancel := context.WithTimeout(context.Background(), defaultTestShortTimeout)
	defer cancel()
	makeTestRPCAndVerifyError(ctx, t, cc, codes.Unavailable, errors.New("RLS response's target list does not contain any entries for key"))

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

// Test verifies the scenario where there is a matching entry in the data cache
// which is valid and there is no pending request. The pick is expected to be