clientv3: fix sync base

It is not correct to use WithPrefix. Range end will change in every
internal batch.

clientv3/integration/mirror_test.go

@@ -15,6 +15,7 @@
 package integration
 
 import (
+	"fmt"
 	"reflect"
 	"testing"
 	"time"
@@ -69,3 +70,37 @@ func TestMirrorSync(t *testing.T) {
 		t.Fatal("failed to receive update in one second")
 	}
 }
+
+func TestMirrorSyncBase(t *testing.T) {
+	cluster := integration.NewClusterV3(nil, &integration.ClusterConfig{Size: 1})
+	defer cluster.Terminate(nil)
+
+	cli := cluster.Client(0)
+	ctx := context.TODO()
+
+	for i := 0; i < 2000; i++ {
+		if _, err := cli.Put(ctx, fmt.Sprintf("test%d", i), "test"); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	syncer := mirror.NewSyncer(cli, "test", 0)
+	respCh, errCh := syncer.SyncBase(ctx)
+
+	count := 0
+
+	for resp := range respCh {
+		count = count + len(resp.Kvs)
+		if !resp.More {
+			break
+		}
+	}
+
+	for err := range errCh {
+		t.Fatalf("unexpected error %v", err)
+	}
+
+	if count != 2000 {
+		t.Errorf("unexpected kv count: %d", count)
+	}
+}

clientv3/mirror/syncer.go

@@ -78,7 +78,7 @@ func (s *syncer) SyncBase(ctx context.Context) (<-chan clientv3.GetResponse, cha
 			// If len(s.prefix) != 0, we will sync key-value space with given prefix.
 			// We then range from the prefix to the next prefix if exists. Or we will
 			// range from the prefix to the end if the next prefix does not exists.
-			opts = append(opts, clientv3.WithPrefix())
+			opts = append(opts, clientv3.WithRange(clientv3.GetPrefixRangeEnd(s.prefix)))
 			key = s.prefix
 		}