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// Copyright 2017 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 clientv3util_test
import (
"log"
"github.com/coreos/etcd/clientv3"
"github.com/coreos/etcd/clientv3/clientv3util"
"golang.org/x/net/context"
)
func ExampleKeyExists_put() {
cli, err := clientv3.New(clientv3.Config{
Endpoints: []string{"127.0.0.1:2379"},
})
if err != nil {
log.Fatal(err)
}
defer cli.Close()
kvc := clientv3.NewKV(cli)
// perform a put only if key is missing
// It is useful to do the check atomically to avoid overwriting
// the existing key which would generate potentially unwanted events,
// unless of course you wanted to do an overwrite no matter what.
_, err = kvc.Txn(context.Background()).
If(clientv3util.KeyMissing("purpleidea")).
Then(clientv3.OpPut("purpleidea", "hello world")).
Commit()
if err != nil {
log.Fatal(err)
}
}
func ExampleKeyExists_delete() {
cli, err := clientv3.New(clientv3.Config{
Endpoints: []string{"127.0.0.1:2379"},
})
if err != nil {
log.Fatal(err)
}
defer cli.Close()
kvc := clientv3.NewKV(cli)
// perform a delete only if key already exists
_, err = kvc.Txn(context.Background()).
If(clientv3util.KeyExists("purpleidea")).
Then(clientv3.OpDelete("purpleidea")).
Commit()
if err != nil {
log.Fatal(err)
}
}
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