Method TestWRRMetricsBasic

balancer/weightedroundrobin/balancer_test.go:220–251

TestWRRMetricsBasic tests metrics emitted from the WRR balancer. It configures a weighted round robin balancer as the top level balancer of a ClientConn, and configures a fake stats handler on the ClientConn to receive metrics. It verifies stats emitted from the Weighted Round Robin Balancer on bala

(t *testing.T)

// from the most recently synced state of the system (picker/scheduler) from the
// test body.
func (s) TestWRRMetricsBasic(t *testing.T) {
	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
	defer cancel()

	srv := startServer(t, reportCall)
	sc := svcConfig(t, testMetricsConfig)

	tmr := stats.NewTestMetricsRecorder()
	if err := srv.StartClient(grpc.WithDefaultServiceConfig(sc), grpc.WithStatsHandler(tmr)); err != nil {
		t.Fatalf("Error starting client: %v", err)
	}
	srv.callMetrics.SetQPS(float64(1))

	if _, err := srv.Client.EmptyCall(ctx, &testpb.Empty{}); err != nil {
		t.Fatalf("Error from EmptyCall: %v", err)
	}

	if got, _ := tmr.Metric("grpc.lb.wrr.rr_fallback"); got != 1 {
		t.Fatalf("Unexpected data for metric %v, got: %v, want: %v", "grpc.lb.wrr.rr_fallback", got, 1)
	}
	if got, _ := tmr.Metric("grpc.lb.wrr.endpoint_weight_stale"); got != 0 {
		t.Fatalf("Unexpected data for metric %v, got: %v, want: %v", "grpc.lb.wrr.endpoint_weight_stale", got, 0)
	}
	if got, _ := tmr.Metric("grpc.lb.wrr.endpoint_weight_not_yet_usable"); got != 1 {
		t.Fatalf("Unexpected data for metric %v, got: %v, want: %v", "grpc.lb.wrr.endpoint_weight_not_yet_usable", got, 1)
	}
	// Unusable, so no endpoint weight. Due to only one SubConn, this will never
	// update the weight. Thus, this will stay 0.
	if got, _ := tmr.Metric("grpc.lb.wrr.endpoint_weight_stale"); got != 0 {
		t.Fatalf("Unexpected data for metric %v, got: %v, want: %v", "grpc.lb.wrr.endpoint_weight_stale", got, 0)
	}
}

// Tests two addresses with ORCA reporting disabled (should fall back to pure
// RR).