| // 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 ( |
| "context" |
| "log" |
| |
| "github.com/coreos/etcd/clientv3" |
| "github.com/coreos/etcd/clientv3/clientv3util" |
| ) |
| |
| 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) |
| } |
| } |