bytes_txn_impl.go

// Copyright (c) 2017 Cisco and/or its affiliates.
//
// 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 etcdv3

import (
	"github.com/coreos/etcd/clientv3"
	"github.com/ligato/cn-infra/db/keyval"
	"golang.org/x/net/context"
)

// Txn allows to group operations into the transaction. Transaction executes
// multiple operations in a more efficient way in contrast to executing
// them one by one.
type bytesTxn struct {
	ops []clientv3.Op
	kv  clientv3.KV
}

// Put adds a new 'put' operation to a previously created transaction.
// If the <key> does not exist in the data store, a new key-value item
// will be added to the data store. If <key> exists in the data store,
// the existing value will be overwritten with the <value> from this
// operation.
func (tx *bytesTxn) Put(key string, value []byte) keyval.BytesTxn {
	tx.ops = append(tx.ops, clientv3.OpPut(key, string(value)))
	return tx
}

// Delete adds a new 'delete' operation to a previously created
// transaction. If <key> exists in the data store, the associated value
// will get removed.
func (tx *bytesTxn) Delete(key string) keyval.BytesTxn {
	tx.ops = append(tx.ops, clientv3.OpDelete(key))
	return tx
}

// Commit commits all operations in a transaction to the data store.
// Commit is atomic - either all operations in the transaction are
// committed to the data store, or none of them.
func (tx *bytesTxn) Commit() error {
	_, err := tx.kv.Txn(context.Background()).Then(tx.ops...).Commit()
	if err != nil {
		return err
	}
	return nil
}