diff --git a/vendor/go.etcd.io/etcd/clientv3/txn.go b/vendor/go.etcd.io/etcd/clientv3/txn.go
new file mode 100644
index 0000000..c3c2d24
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/clientv3/txn.go
@@ -0,0 +1,151 @@
+// Copyright 2016 The etcd 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 clientv3
+
+import (
+	"context"
+	"sync"
+
+	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
+
+	"google.golang.org/grpc"
+)
+
+// Txn is the interface that wraps mini-transactions.
+//
+//	 Txn(context.TODO()).If(
+//	  Compare(Value(k1), ">", v1),
+//	  Compare(Version(k1), "=", 2)
+//	 ).Then(
+//	  OpPut(k2,v2), OpPut(k3,v3)
+//	 ).Else(
+//	  OpPut(k4,v4), OpPut(k5,v5)
+//	 ).Commit()
+//
+type Txn interface {
+	// If takes a list of comparison. If all comparisons passed in succeed,
+	// the operations passed into Then() will be executed. Or the operations
+	// passed into Else() will be executed.
+	If(cs ...Cmp) Txn
+
+	// Then takes a list of operations. The Ops list will be executed, if the
+	// comparisons passed in If() succeed.
+	Then(ops ...Op) Txn
+
+	// Else takes a list of operations. The Ops list will be executed, if the
+	// comparisons passed in If() fail.
+	Else(ops ...Op) Txn
+
+	// Commit tries to commit the transaction.
+	Commit() (*TxnResponse, error)
+}
+
+type txn struct {
+	kv  *kv
+	ctx context.Context
+
+	mu    sync.Mutex
+	cif   bool
+	cthen bool
+	celse bool
+
+	isWrite bool
+
+	cmps []*pb.Compare
+
+	sus []*pb.RequestOp
+	fas []*pb.RequestOp
+
+	callOpts []grpc.CallOption
+}
+
+func (txn *txn) If(cs ...Cmp) Txn {
+	txn.mu.Lock()
+	defer txn.mu.Unlock()
+
+	if txn.cif {
+		panic("cannot call If twice!")
+	}
+
+	if txn.cthen {
+		panic("cannot call If after Then!")
+	}
+
+	if txn.celse {
+		panic("cannot call If after Else!")
+	}
+
+	txn.cif = true
+
+	for i := range cs {
+		txn.cmps = append(txn.cmps, (*pb.Compare)(&cs[i]))
+	}
+
+	return txn
+}
+
+func (txn *txn) Then(ops ...Op) Txn {
+	txn.mu.Lock()
+	defer txn.mu.Unlock()
+
+	if txn.cthen {
+		panic("cannot call Then twice!")
+	}
+	if txn.celse {
+		panic("cannot call Then after Else!")
+	}
+
+	txn.cthen = true
+
+	for _, op := range ops {
+		txn.isWrite = txn.isWrite || op.isWrite()
+		txn.sus = append(txn.sus, op.toRequestOp())
+	}
+
+	return txn
+}
+
+func (txn *txn) Else(ops ...Op) Txn {
+	txn.mu.Lock()
+	defer txn.mu.Unlock()
+
+	if txn.celse {
+		panic("cannot call Else twice!")
+	}
+
+	txn.celse = true
+
+	for _, op := range ops {
+		txn.isWrite = txn.isWrite || op.isWrite()
+		txn.fas = append(txn.fas, op.toRequestOp())
+	}
+
+	return txn
+}
+
+func (txn *txn) Commit() (*TxnResponse, error) {
+	txn.mu.Lock()
+	defer txn.mu.Unlock()
+
+	r := &pb.TxnRequest{Compare: txn.cmps, Success: txn.sus, Failure: txn.fas}
+
+	var resp *pb.TxnResponse
+	var err error
+	resp, err = txn.kv.remote.Txn(txn.ctx, r, txn.callOpts...)
+	if err != nil {
+		return nil, toErr(txn.ctx, err)
+	}
+	return (*TxnResponse)(resp), nil
+}