Unpin grpc version and use serviceConfig to set the load balancer (#1786

)

* Unpin grpc version and use serviceConfig to set loadbalancer (WIP)

Signed-off-by: Jude Wang <judew@uber.com>

* Undo idl change

Signed-off-by: Yuri Shkuro <ys@uber.com>

Gopkg.toml

@@ -113,7 +113,7 @@ required = [
 
 [[constraint]]
   name = "google.golang.org/grpc"
-  version = "=1.20.1"
+  version = "^1.20.1"
 
 [[constraint]]
   name = "github.com/olivere/elastic"

cmd/agent/app/reporter/grpc/builder.go

@@ -25,7 +25,6 @@ import (
 	grpc_retry "github.com/grpc-ecosystem/go-grpc-middleware/retry"
 	"go.uber.org/zap"
 	"google.golang.org/grpc"
-	"google.golang.org/grpc/balancer/roundrobin"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/resolver"
 	"google.golang.org/grpc/resolver/manual"
@@ -130,7 +129,7 @@ func (b *ConnBuilder) CreateConnection(logger *zap.Logger) (*grpc.ClientConn, er
 			dialTarget = b.CollectorHostPorts[0]
 		}
 	}
-	dialOptions = append(dialOptions, grpc.WithBalancerName(roundrobin.Name))
+	dialOptions = append(dialOptions, grpc.WithDefaultServiceConfig(grpcresolver.GRPCServiceConfig))
 	dialOptions = append(dialOptions, grpc.WithUnaryInterceptor(grpc_retry.UnaryClientInterceptor(grpc_retry.WithMax(b.MaxRetry))))
 	return grpc.Dial(dialTarget, dialOptions...)
 }

pkg/discovery/grpcresolver/grpc_resolver.go

@@ -29,6 +29,9 @@ import (
 	"github.com/jaegertracing/jaeger/pkg/discovery"
 )
 
+// GRPCServiceConfig provides grpc service config
+const GRPCServiceConfig = `{"loadBalancingPolicy":"round_robin"}`
+
 // Resolver uses notifier to fetch list of available hosts
 type Resolver struct {
 	scheme            string

pkg/discovery/grpcresolver/grpc_resolver_test.go

@@ -25,7 +25,6 @@ import (
 	"github.com/stretchr/testify/assert"
 	"go.uber.org/zap"
 	"google.golang.org/grpc"
-	"google.golang.org/grpc/balancer/roundrobin"
 	"google.golang.org/grpc/peer"
 	"google.golang.org/grpc/resolver"
 	grpctest "google.golang.org/grpc/test/grpc_testing"
@@ -143,7 +142,7 @@ func TestGRPCResolverRoundRobin(t *testing.T) {
 			res := New(notifier, discoverer, zap.NewNop(), test.minPeers)
 			defer resolver.UnregisterForTesting(res.Scheme())
 
-			cc, err := grpc.Dial(res.Scheme()+":///round_robin", grpc.WithInsecure(), grpc.WithBalancerName(roundrobin.Name))
+			cc, err := grpc.Dial(res.Scheme()+":///round_robin", grpc.WithInsecure(), grpc.WithDefaultServiceConfig(GRPCServiceConfig))
 			assert.NoError(t, err, "could not dial using resolver's scheme")
 			defer cc.Close()