snapshot of https://github.com/grpc/grpc-go.git (master, 2026-09-15; blobs > 131072B omitted)

balancer/weightedroundrobin/metrics_test.go

@@ -0,0 +1,173 @@
+/*
+ *
+ * Copyright 2024 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package weightedroundrobin
+
+import (
+	"testing"
+	"time"
+
+	"google.golang.org/grpc/internal/grpctest"
+	iserviceconfig "google.golang.org/grpc/internal/serviceconfig"
+	"google.golang.org/grpc/internal/testutils/stats"
+)
+
+type s struct {
+	grpctest.Tester
+}
+
+func Test(t *testing.T) {
+	grpctest.RunSubTests(t, s{})
+}
+
+// TestWRR_Metrics_SubConnWeight tests different scenarios for the weight call
+// on a weighted SubConn, and expects certain metrics for each of these
+// scenarios.
+func (s) TestWRR_Metrics_SubConnWeight(t *testing.T) {
+	tests := []struct {
+		name                           string
+		weightExpirationPeriod         time.Duration
+		blackoutPeriod                 time.Duration
+		lastUpdated                    time.Time
+		nonEmpty                       time.Time
+		nowTime                        time.Time
+		endpointWeightStaleWant        float64
+		endpointWeightNotYetUsableWant float64
+		endpointWeightWant             float64
+	}{
+		// The weighted SubConn's lastUpdated field hasn't been set, so this
+		// SubConn's weight is not yet usable. Thus, should emit that endpoint
+		// weight is not yet usable, and 0 for weight.
+		{
+			name:                           "no weight set",
+			weightExpirationPeriod:         time.Second,
+			blackoutPeriod:                 time.Second,
+			nowTime:                        time.Now(),
+			endpointWeightStaleWant:        0,
+			endpointWeightNotYetUsableWant: 1,
+			endpointWeightWant:             0,
+		},
+		{
+			name:                           "weight expiration",
+			lastUpdated:                    time.Now(),
+			weightExpirationPeriod:         2 * time.Second,
+			blackoutPeriod:                 time.Second,
+			nowTime:                        time.Now().Add(100 * time.Second),
+			endpointWeightStaleWant:        1,
+			endpointWeightNotYetUsableWant: 0,
+			endpointWeightWant:             0,
+		},
+		{
+			name:                           "in blackout period",
+			lastUpdated:                    time.Now(),
+			weightExpirationPeriod:         time.Minute,
+			blackoutPeriod:                 10 * time.Second,
+			nowTime:                        time.Now(),
+			endpointWeightStaleWant:        0,
+			endpointWeightNotYetUsableWant: 1,
+			endpointWeightWant:             0,
+		},
+		{
+			name:                           "normal weight",
+			lastUpdated:                    time.Now(),
+			nonEmpty:                       time.Now(),
+			weightExpirationPeriod:         time.Minute,
+			blackoutPeriod:                 time.Second,
+			nowTime:                        time.Now().Add(10 * time.Second),
+			endpointWeightStaleWant:        0,
+			endpointWeightNotYetUsableWant: 0,
+			endpointWeightWant:             3,
+		},
+		{
+			name:                           "weight expiration takes precdedence over blackout",
+			lastUpdated:                    time.Now(),
+			nonEmpty:                       time.Now(),
+			weightExpirationPeriod:         time.Second,
+			blackoutPeriod:                 time.Minute,
+			nowTime:                        time.Now().Add(10 * time.Second),
+			endpointWeightStaleWant:        1,
+			endpointWeightNotYetUsableWant: 0,
+			endpointWeightWant:             0,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			tmr := stats.NewTestMetricsRecorder()
+			wsc := &endpointWeight{
+				metricsRecorder: tmr,
+				weightVal:       3,
+				lastUpdated:     test.lastUpdated,
+				nonEmptySince:   test.nonEmpty,
+			}
+			wsc.weight(test.nowTime, test.weightExpirationPeriod, test.blackoutPeriod, true)
+
+			if got, _ := tmr.Metric("grpc.lb.wrr.endpoint_weight_stale"); got != test.endpointWeightStaleWant {
+				t.Fatalf("Unexpected data for metric %v, got: %v, want: %v", "grpc.lb.wrr.endpoint_weight_stale", got, test.endpointWeightStaleWant)
+			}
+			if got, _ := tmr.Metric("grpc.lb.wrr.endpoint_weight_not_yet_usable"); got != test.endpointWeightNotYetUsableWant {
+				t.Fatalf("Unexpected data for metric %v, got: %v, want: %v", "grpc.lb.wrr.endpoint_weight_not_yet_usable", got, test.endpointWeightNotYetUsableWant)
+			}
+			if got, _ := tmr.Metric("grpc.lb.wrr.endpoint_weight_stale"); got != test.endpointWeightStaleWant {
+				t.Fatalf("Unexpected data for metric %v, got: %v, want: %v", "grpc.lb.wrr.endpoint_weight_stale", got, test.endpointWeightStaleWant)
+			}
+		})
+	}
+
+}
+
+// TestWRR_Metrics_Scheduler_RR_Fallback tests the round robin fallback metric
+// for scheduler updates. It tests the case with one SubConn, and two SubConns
+// with no weights. Both of these should emit a count metric for round robin
+// fallback.
+func (s) TestWRR_Metrics_Scheduler_RR_Fallback(t *testing.T) {
+	tmr := stats.NewTestMetricsRecorder()
+	ew := &endpointWeight{
+		metricsRecorder: tmr,
+		weightVal:       0,
+	}
+
+	p := &picker{
+		cfg: &lbConfig{
+			BlackoutPeriod:         iserviceconfig.Duration(10 * time.Second),
+			WeightExpirationPeriod: iserviceconfig.Duration(3 * time.Minute),
+		},
+		weightedPickers: []pickerWeightedEndpoint{{weightedEndpoint: ew}},
+		metricsRecorder: tmr,
+	}
+	// There is only one SubConn, so no matter if the SubConn has a weight or
+	// not will fallback to round robin.
+	p.regenerateScheduler()
+	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)
+	}
+	tmr.ClearMetrics()
+
+	// With two SubConns, if neither of them have weights, it will also fallback
+	// to round robin.
+	ew2 := &endpointWeight{
+		target:          "target",
+		metricsRecorder: tmr,
+		weightVal:       0,
+	}
+	p.weightedPickers = append(p.weightedPickers, pickerWeightedEndpoint{weightedEndpoint: ew2})
+	p.regenerateScheduler()
+	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)
+	}
+}