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67 lines
1.8 KiB
Go
67 lines
1.8 KiB
Go
// Copyright 2017 The etcd Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package clientv3util_test
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import (
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"context"
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"log"
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"github.com/coreos/etcd/clientv3"
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"github.com/coreos/etcd/clientv3/clientv3util"
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)
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func ExampleKeyExists_put() {
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cli, err := clientv3.New(clientv3.Config{
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Endpoints: []string{"127.0.0.1:2379"},
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})
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if err != nil {
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log.Fatal(err)
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}
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defer cli.Close()
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kvc := clientv3.NewKV(cli)
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// perform a put only if key is missing
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// It is useful to do the check (transactionally) to avoid overwriting
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// the existing key which would generate potentially unwanted events,
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// unless of course you wanted to do an overwrite no matter what.
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_, err = kvc.Txn(context.Background()).
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If(clientv3util.KeyMissing("purpleidea")).
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Then(clientv3.OpPut("purpleidea", "hello world")).
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Commit()
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if err != nil {
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log.Fatal(err)
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}
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}
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func ExampleKeyExists_delete() {
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cli, err := clientv3.New(clientv3.Config{
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Endpoints: []string{"127.0.0.1:2379"},
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})
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if err != nil {
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log.Fatal(err)
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}
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defer cli.Close()
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kvc := clientv3.NewKV(cli)
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// perform a delete only if key already exists
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_, err = kvc.Txn(context.Background()).
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If(clientv3util.KeyExists("purpleidea")).
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Then(clientv3.OpDelete("purpleidea")).
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Commit()
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if err != nil {
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log.Fatal(err)
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}
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}
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