clientv3: filter learners members during autosync

This change is to ensure that all members returned during the client's
AutoSync are started and are not learners, which are not valid
etcd members to make requests to.

client/v3/client.go

@@ -185,7 +185,9 @@ func (c *Client) Sync(ctx context.Context) error {
 	}
 	var eps []string
 	for _, m := range mresp.Members {
-		eps = append(eps, m.ClientURLs...)
+		if len(m.Name) != 0 && !m.IsLearner {
+			eps = append(eps, m.ClientURLs...)
+		}
 	}
 	c.SetEndpoints(eps...)
 	return nil

client/v3/client_test.go

@@ -17,13 +17,14 @@ package clientv3
 import (
 	"context"
 	"fmt"
-	"go.uber.org/zap"
 	"net"
 	"testing"
 	"time"
 
+	"go.etcd.io/etcd/api/v3/etcdserverpb"
 	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
 	"go.etcd.io/etcd/client/pkg/v3/testutil"
+	"go.uber.org/zap"
 	"go.uber.org/zap/zaptest"
 
 	"google.golang.org/grpc"
@@ -198,3 +199,49 @@ func TestZapWithLogger(t *testing.T) {
 		t.Errorf("WithZapLogger should modify *zap.Logger")
 	}
 }
+
+func TestSyncFiltersMembers(t *testing.T) {
+	c, _ := NewClient(t, Config{Endpoints: []string{"http://254.0.0.1:12345"}})
+	defer c.Close()
+	c.Cluster = &mockCluster{
+		[]*etcdserverpb.Member{
+			{ID: 0, Name: "", ClientURLs: []string{"http://254.0.0.1:12345"}, IsLearner: false},
+			{ID: 1, Name: "isStarted", ClientURLs: []string{"http://254.0.0.2:12345"}, IsLearner: true},
+			{ID: 2, Name: "isStartedAndNotLearner", ClientURLs: []string{"http://254.0.0.3:12345"}, IsLearner: false},
+		},
+	}
+	c.Sync(context.Background())
+
+	endpoints := c.Endpoints()
+	if len(endpoints) != 1 || endpoints[0] != "http://254.0.0.3:12345" {
+		t.Error("Client.Sync uses learner and/or non-started member client URLs")
+	}
+}
+
+type mockCluster struct {
+	members []*etcdserverpb.Member
+}
+
+func (mc *mockCluster) MemberList(ctx context.Context) (*MemberListResponse, error) {
+	return &MemberListResponse{Members: mc.members}, nil
+}
+
+func (mc *mockCluster) MemberAdd(ctx context.Context, peerAddrs []string) (*MemberAddResponse, error) {
+	return nil, nil
+}
+
+func (mc *mockCluster) MemberAddAsLearner(ctx context.Context, peerAddrs []string) (*MemberAddResponse, error) {
+	return nil, nil
+}
+
+func (mc *mockCluster) MemberRemove(ctx context.Context, id uint64) (*MemberRemoveResponse, error) {
+	return nil, nil
+}
+
+func (mc *mockCluster) MemberUpdate(ctx context.Context, id uint64, peerAddrs []string) (*MemberUpdateResponse, error) {
+	return nil, nil
+}
+
+func (mc *mockCluster) MemberPromote(ctx context.Context, id uint64) (*MemberPromoteResponse, error) {
+	return nil, nil
+}