xds: Remove temporary environment variable for least request.

Fixes grpc#8228.

Author: atollena

test/xds/xds_client_custom_lb_test.go

@@ -28,7 +28,6 @@ import (
 	_ "google.golang.org/grpc/balancer/leastrequest"       // To register least_request
 	_ "google.golang.org/grpc/balancer/weightedroundrobin" // To register weighted_round_robin
 	"google.golang.org/grpc/credentials/insecure"
-	"google.golang.org/grpc/internal/envconfig"
 	"google.golang.org/grpc/internal/stubserver"
 	"google.golang.org/grpc/internal/testutils"
 	"google.golang.org/grpc/internal/testutils/roundrobin"
@@ -94,12 +93,6 @@ func clusterWithLBConfiguration(t *testing.T, clusterName, edsServiceName string
 // first) child load balancing policy, and asserts the correct distribution
 // based on the locality weights and the endpoint picking policy specified.
 func (s) TestWrrLocality(t *testing.T) {
-	oldLeastRequestLBSupport := envconfig.LeastRequestLB
-	envconfig.LeastRequestLB = true
-	defer func() {
-		envconfig.LeastRequestLB = oldLeastRequestLBSupport
-	}()
-
 	backend1 := stubserver.StartTestService(t, nil)
 	port1 := testutils.ParsePort(t, backend1.Address)
 	defer backend1.Stop()

xds/internal/xdsclient/xdslbregistry/converter/converter.go

@@ -32,7 +32,6 @@ import (
 	"google.golang.org/grpc/balancer/pickfirst"
 	"google.golang.org/grpc/balancer/roundrobin"
 	"google.golang.org/grpc/balancer/weightedroundrobin"
-	"google.golang.org/grpc/internal/envconfig"
 	internalserviceconfig "google.golang.org/grpc/internal/serviceconfig"
 	"google.golang.org/grpc/xds/internal/balancer/ringhash"
 	"google.golang.org/grpc/xds/internal/balancer/wrrlocality"
@@ -176,9 +175,6 @@ func convertWeightedRoundRobinProtoToServiceConfig(rawProto []byte, _ int) (json
 }
 
 func convertLeastRequestProtoToServiceConfig(rawProto []byte, _ int) (json.RawMessage, error) {
-	if !envconfig.LeastRequestLB {
-		return nil, nil
-	}
 	lrProto := &v3leastrequestpb.LeastRequest{}
 	if err := proto.Unmarshal(rawProto, lrProto); err != nil {
 		return nil, fmt.Errorf("failed to unmarshal resource: %v", err)

xds/internal/xdsclient/xdslbregistry/xdslbregistry_test.go

@@ -27,7 +27,6 @@ import (
 	"github.com/google/go-cmp/cmp"
 	_ "google.golang.org/grpc/balancer/roundrobin"
 	"google.golang.org/grpc/internal/balancer/stub"
-	"google.golang.org/grpc/internal/envconfig"
 	"google.golang.org/grpc/internal/grpctest"
 	"google.golang.org/grpc/internal/pretty"
 	internalserviceconfig "google.golang.org/grpc/internal/serviceconfig"
@@ -69,17 +68,13 @@ func wrrLocalityBalancerConfig(childPolicy *internalserviceconfig.BalancerConfig
 }
 
 func (s) TestConvertToServiceConfigSuccess(t *testing.T) {
-	defer func(old bool) { envconfig.LeastRequestLB = old }(envconfig.LeastRequestLB)
-	envconfig.LeastRequestLB = false
-
 	const customLBPolicyName = "myorg.MyCustomLeastRequestPolicy"
 	stub.Register(customLBPolicyName, stub.BalancerFuncs{})
 
 	tests := []struct {
 		name       string
 		policy     *v3clusterpb.LoadBalancingPolicy
 		wantConfig string // JSON config
-		lrEnabled  bool
 	}{
 		{
 			name: "ring_hash",
@@ -112,7 +107,6 @@ func (s) TestConvertToServiceConfigSuccess(t *testing.T) {
 				},
 			},
 			wantConfig: `[{"least_request_experimental": { "choiceCount": 3 }}]`,
-			lrEnabled:  true,
 		},
 		{
 			name: "pick_first_shuffle",
@@ -197,26 +191,6 @@ func (s) TestConvertToServiceConfigSuccess(t *testing.T) {
 			},
 			wantConfig: `[{"pick_first": { "shuffleAddressList": true }}]`,
 		},
-		{
-			name: "least_request_disabled_pf_rr_use_first_supported",
-			policy: &v3clusterpb.LoadBalancingPolicy{
-				Policies: []*v3clusterpb.LoadBalancingPolicy_Policy{
-					{
-						TypedExtensionConfig: &v3corepb.TypedExtensionConfig{
-							TypedConfig: testutils.MarshalAny(t, &v3leastrequestpb.LeastRequest{
-								ChoiceCount: wrapperspb.UInt32(32),
-							}),
-						},
-					},
-					{
-						TypedExtensionConfig: &v3corepb.TypedExtensionConfig{
-							TypedConfig: testutils.MarshalAny(t, &v3roundrobinpb.RoundRobin{}),
-						},
-					},
-				},
-			},
-			wantConfig: `[{"round_robin": {}}]`,
-		},
 		{
 			name: "custom_lb_type_v3_struct",
 			policy: &v3clusterpb.LoadBalancingPolicy{
@@ -307,10 +281,6 @@ func (s) TestConvertToServiceConfigSuccess(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			if test.lrEnabled {
-				defer func(old bool) { envconfig.LeastRequestLB = old }(envconfig.LeastRequestLB)
-				envconfig.LeastRequestLB = true
-			}
 			rawJSON, err := xdslbregistry.ConvertToServiceConfig(test.policy, 0)
 			if err != nil {
 				t.Fatalf("ConvertToServiceConfig(%s) failed: %v", pretty.ToJSON(test.policy), err)

xds/internal/xdsclient/xdsresource/tests/unmarshal_cds_test.go

@@ -27,7 +27,6 @@ import (
 	"github.com/google/go-cmp/cmp/cmpopts"
 	"google.golang.org/grpc/balancer/leastrequest"
 	"google.golang.org/grpc/internal/balancer/stub"
-	"google.golang.org/grpc/internal/envconfig"
 	"google.golang.org/grpc/internal/grpctest"
 	iserviceconfig "google.golang.org/grpc/internal/serviceconfig"
 	"google.golang.org/grpc/internal/testutils"
@@ -105,8 +104,6 @@ func (s) TestValidateCluster_Success(t *testing.T) {
 		t.Fatalf("Failed to create server config for testing: %v", err)
 	}
 
-	defer func(old bool) { envconfig.LeastRequestLB = old }(envconfig.LeastRequestLB)
-	envconfig.LeastRequestLB = true
 	tests := []struct {
 		name         string
 		cluster      *v3clusterpb.Cluster

xds/internal/xdsclient/xdsresource/unmarshal_cds.go

@@ -133,10 +133,6 @@ func validateClusterAndConstructClusterUpdate(cluster *v3clusterpb.Cluster, serv
 		rhLBCfg := []byte(fmt.Sprintf("{\"minRingSize\": %d, \"maxRingSize\": %d}", minSize, maxSize))
 		lbPolicy = []byte(fmt.Sprintf(`[{"ring_hash_experimental": %s}]`, rhLBCfg))
 	case v3clusterpb.Cluster_LEAST_REQUEST:
-		if !envconfig.LeastRequestLB {
-			return ClusterUpdate{}, fmt.Errorf("unexpected lbPolicy %v in response: %+v", cluster.GetLbPolicy(), cluster)
-		}
-
 		// "The configuration for the Least Request LB policy is the
 		// least_request_lb_config field. The field is optional; if not present,
 		// defaults will be assumed for all of its values." - A48