etcd/clientv3/example_kv_test.go

// Copyright 2016 CoreOS, Inc.
//
// 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_test

import (
	"fmt"
	"log"

	"github.com/coreos/etcd/clientv3"
	"golang.org/x/net/context"
)

func ExampleKV_put() {
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   endpoints,
		DialTimeout: dialTimeout,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer cli.Close()

	ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
	resp, err := cli.Put(ctx, "sample_key", "sample_value")
	cancel()
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println("current revision:", resp.Header.Revision) // revision start at 1
	// current revision: 2
}

func ExampleKV_get() {
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   endpoints,
		DialTimeout: dialTimeout,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer cli.Close()

	_, err = cli.Put(context.TODO(), "foo", "bar")
	if err != nil {
		log.Fatal(err)
	}

	ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
	resp, err := cli.Get(ctx, "foo")
	cancel()
	if err != nil {
		log.Fatal(err)
	}
	for _, ev := range resp.Kvs {
		fmt.Printf("%s : %s\n", ev.Key, ev.Value)
	}
	// foo : bar
}

func ExampleKV_getSortedPrefix() {
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   endpoints,
		DialTimeout: dialTimeout,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer cli.Close()

	for i := range make([]int, 3) {
		ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
		_, err = cli.Put(ctx, fmt.Sprintf("key_%d", i), "value")
		cancel()
		if err != nil {
			log.Fatal(err)
		}
	}

	ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
	resp, err := cli.Get(ctx, "key", clientv3.WithPrefix(), clientv3.WithSort(clientv3.SortByKey, clientv3.SortDescend))
	cancel()
	if err != nil {
		log.Fatal(err)
	}
	for _, ev := range resp.Kvs {
		fmt.Printf("%s : %s\n", ev.Key, ev.Value)
	}
	// key_2 : value
	// key_1 : value
	// key_0 : value
}

func ExampleKV_delete() {
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   endpoints,
		DialTimeout: dialTimeout,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer cli.Close()

	ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
	resp, err := cli.Delete(ctx, "key", clientv3.WithPrefix())
	cancel()
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println("Deleted", resp.Deleted, "keys")
	// Deleted n keys
}

func ExampleKV_compact() {
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   endpoints,
		DialTimeout: dialTimeout,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer cli.Close()

	ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
	resp, err := cli.Get(ctx, "foo")
	cancel()
	if err != nil {
		log.Fatal(err)
	}
	compRev := resp.Header.Revision // specify compact revision of your choice

	ctx, cancel = context.WithTimeout(context.Background(), requestTimeout)
	err = cli.Compact(ctx, compRev)
	cancel()
	if err != nil {
		log.Fatal(err)
	}
}

func ExampleKV_txn() {
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   endpoints,
		DialTimeout: dialTimeout,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer cli.Close()

	kvc := clientv3.NewKV(cli)

	_, err = kvc.Put(context.TODO(), "key", "xyz")
	if err != nil {
		log.Fatal(err)
	}

	ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
	_, err = kvc.Txn(ctx).
		If(clientv3.Compare(clientv3.Value("key"), ">", "abc")). // txn value comparisons are lexical
		Then(clientv3.OpPut("key", "XYZ")).                      // this runs, since 'xyz' > 'abc'
		Else(clientv3.OpPut("key", "ABC")).
		Commit()
	cancel()
	if err != nil {
		log.Fatal(err)
	}

	gresp, err := kvc.Get(context.TODO(), "key")
	cancel()
	if err != nil {
		log.Fatal(err)
	}
	for _, ev := range gresp.Kvs {
		fmt.Printf("%s : %s\n", ev.Key, ev.Value)
	}
	// key : XYZ
}

func ExampleKV_do() {
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   endpoints,
		DialTimeout: dialTimeout,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer cli.Close()

	ops := []clientv3.Op{
		clientv3.OpPut("put-key", "123"),
		clientv3.OpGet("put-key"),
		clientv3.OpPut("put-key", "456")}

	for _, op := range ops {
		if _, err := cli.Do(context.TODO(), op); err != nil {
			log.Fatal(err)
		}
	}
}