Add GRPCRoute weighted backendRefs test

Author: sarthyparty

conformance/tests/grpcroute-weight.go

@@ -0,0 +1,158 @@
+/*
+Copyright 2024 The Kubernetes 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 tests
+
+import (
+	"cmp"
+	"errors"
+	"fmt"
+	"math"
+	"slices"
+	"strings"
+	"sync"
+	"testing"
+
+	"golang.org/x/sync/errgroup"
+	"google.golang.org/grpc/codes"
+	"k8s.io/apimachinery/pkg/types"
+	v1 "sigs.k8s.io/gateway-api/apis/v1"
+	pb "sigs.k8s.io/gateway-api/conformance/echo-basic/grpcechoserver"
+
+	"sigs.k8s.io/gateway-api/conformance/utils/grpc"
+	"sigs.k8s.io/gateway-api/conformance/utils/kubernetes"
+	"sigs.k8s.io/gateway-api/conformance/utils/suite"
+	"sigs.k8s.io/gateway-api/pkg/features"
+)
+
+func init() {
+	ConformanceTests = append(ConformanceTests, GRPCRouteWeight)
+}
+
+var GRPCRouteWeight = suite.ConformanceTest{
+	ShortName:   "GRPCRouteWeight",
+	Description: "An GRPCRoute with weighted backends",
+	Manifests:   []string{"tests/grpcroute-weight.yaml"},
+	Features: []features.FeatureName{
+		features.SupportGateway,
+		features.SupportGRPCRoute,
+	},
+	Test: func(t *testing.T, suite *suite.ConformanceTestSuite) {
+		var (
+			ns      = "gateway-conformance-infra"
+			routeNN = types.NamespacedName{Name: "weighted-backends", Namespace: ns}
+			gwNN    = types.NamespacedName{Name: "same-namespace", Namespace: ns}
+			gwAddr  = kubernetes.GatewayAndRoutesMustBeAccepted(t, suite.Client, suite.TimeoutConfig, suite.ControllerName, kubernetes.NewGatewayRef(gwNN), &v1.GRPCRoute{}, true, routeNN)
+		)
+
+		t.Run("Requests should have a distribution that matches the weight", func(t *testing.T) {
+			expected := grpc.ExpectedResponse{
+				EchoRequest: &pb.EchoRequest{},
+				Response:    grpc.Response{Code: codes.OK},
+				Namespace:   "gateway-conformance-infra",
+			}
+
+			// Assert request succeeds before doing 	our distribution check
+			grpc.MakeRequestAndExpectEventuallyConsistentResponse(t, suite.GRPCClient, suite.TimeoutConfig, gwAddr, expected)
+
+			for i := 0; i < 10; i++ {
+				if err := testGRPCDistribution(t, suite, gwAddr, expected); err != nil {
+					t.Logf("Traffic distribution test failed (%d/10): %s", i+1, err)
+				} else {
+					return
+				}
+			}
+			t.Fatal("Weighted distribution tests failed")
+		})
+	},
+}
+
+func testGRPCDistribution(t *testing.T, suite *suite.ConformanceTestSuite, gwAddr string, expected grpc.ExpectedResponse) error {
+	const (
+		concurrentRequests  = 10
+		tolerancePercentage = 0.05
+		totalRequests       = 500.0
+	)
+	var (
+		grpcClient      = suite.GRPCClient
+		g               errgroup.Group
+		seenMutex       sync.Mutex
+		seen            = make(map[string]float64, 3 /* number of backends */)
+		expectedWeights = map[string]float64{
+			"grpc-infra-backend-v1": 0.7,
+			"grpc-infra-backend-v2": 0.3,
+			"grpc-infra-backend-v3": 0.0,
+		}
+	)
+	g.SetLimit(concurrentRequests)
+	for i := 0.0; i < totalRequests; i++ {
+		g.Go(func() error {
+			resp, err := grpcClient.SendRPC(t, gwAddr, expected, suite.TimeoutConfig.MaxTimeToConsistency)
+			if err != nil {
+				return fmt.Errorf("failed to send gRPC request: %w", err)
+			}
+			if resp.Code != codes.OK {
+				return fmt.Errorf("expected OK response, got %v", resp.Code)
+			}
+
+			seenMutex.Lock()
+			defer seenMutex.Unlock()
+
+			podName := resp.Response.GetAssertions().GetContext().GetPod()
+			for expectedBackend := range expectedWeights {
+				if strings.HasPrefix(podName, expectedBackend) {
+					seen[expectedBackend]++
+					return nil
+				}
+			}
+
+			return fmt.Errorf("request was handled by an unexpected pod %q", podName)
+		})
+	}
+
+	if err := g.Wait(); err != nil {
+		return fmt.Errorf("error while sending requests: %w", err)
+	}
+
+	var errs []error
+	if len(seen) != 2 {
+		errs = append(errs, fmt.Errorf("expected only two backends to receive traffic"))
+	}
+
+	for wantBackend, wantPercent := range expectedWeights {
+		gotCount, ok := seen[wantBackend]
+
+		if !ok && wantPercent != 0.0 {
+			errs = append(errs, fmt.Errorf("expect traffic to hit backend %q - but none was received", wantBackend))
+			continue
+		}
+
+		gotPercent := gotCount / totalRequests
+
+		if math.Abs(gotPercent-wantPercent) > tolerancePercentage {
+			errs = append(errs, fmt.Errorf("backend %q weighted traffic of %v not within tolerance %v (+/-%f)",
+				wantBackend,
+				gotPercent,
+				wantPercent,
+				tolerancePercentage,
+			))
+		}
+	}
+	slices.SortFunc(errs, func(a, b error) int {
+		return cmp.Compare(a.Error(), b.Error())
+	})
+	return errors.Join(errs...)
+}

conformance/tests/grpcroute-weight.yaml

@@ -0,0 +1,19 @@
+apiVersion: gateway.networking.k8s.io/v1
+kind: GRPCRoute
+metadata:
+  name: weighted-backends
+  namespace: gateway-conformance-infra
+spec:
+  parentRefs:
+  - name: same-namespace
+  rules:
+  - backendRefs:
+    - name: grpc-infra-backend-v1
+      port: 8080
+      weight: 70
+    - name: grpc-infra-backend-v2
+      port: 8080
+      weight: 30
+    - name: grpc-infra-backend-v3
+      port: 8080
+      weight: 0