etcd: github.com/coreos/etcd/clientv3/clientv3util Index | Examples | Files

package clientv3util

import "github.com/coreos/etcd/clientv3/clientv3util"

Package clientv3util contains utility functions derived from clientv3.

Index

Examples

Package Files

util.go

func KeyExists Uses

func KeyExists(key string) clientv3.Cmp

KeyExists returns a comparison operation that evaluates to true iff the given key exists. It does this by checking if the key `Version` is greater than 0. It is a useful guard in transaction delete operations.

Code:

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)
}

func KeyMissing Uses

func KeyMissing(key string) clientv3.Cmp

KeyMissing returns a comparison operation that evaluates to true iff the given key does not exist.

Code:

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)
}

Package clientv3util imports 1 packages (graph) and is imported by 19 packages. Updated 2019-08-11. Refresh now. Tools for package owners.