go任务调度5（go操作etcd）

2025-02-02 技术教程

连接etcd：

package mainimport ( "fmt" "go.etcd.io/etcd/clientv3" "time")var ( config clientv3.Config client *clientv3.Client err error)func main() { //客户端配置 config = clientv3.Config{ Endpoints: []string{"0.0.0.0:2379"}, //集群列表 DialTimeout: 5 * time.Second, } //建立连接 if client, err = clientv3.New(config); err != nil { fmt.Println(err) return } client = client}

k-v操作：

package mainimport ( "context" "fmt" "go.etcd.io/etcd/clientv3" //"github.com/coreos/etcd/clientv3" "time")var ( config clientv3.Config client *clientv3.Client err error kv clientv3.KV putResp *clientv3.PutResponse)func main() { //客户端配置 config = clientv3.Config{ Endpoints: []string{"0.0.0.0:2379"}, //集群列表 DialTimeout: 5 * time.Second, } //建立客户端 if client, err = clientv3.New(config); err != nil { fmt.Println(err) return } //操作k-v(用于读写etcd的键值对) kv = clientv3.NewKV(client) //context.TODO()代表什么都不做，占位就可以了 //不在这里指定clientv3.WithPrevKV()，则不能得到putResp.PrevKv.Key,putResp.PrevKv.Value if putResp, err = kv.Put(context.TODO(), "/cron/jobs/job1", "world", clientv3.WithPrevKV()); err != nil { fmt.Println(err) } else { //输出版本号 fmt.Println("Revision:", putResp.Header.Revision) if putResp.PrevKv != nil { //输出上一个k-v fmt.Println(string(putResp.PrevKv.Key), ":", string(putResp.PrevKv.Value)) } }}

运行输出

[root@bogon etcd]# go run demo2.go
Revision: 19
/cron/jobs/job1 : hello
查看：
[root@bogon etcd-v3.3.12-linux-amd64]# ETCDCTL_API=3 ./etcdctl get "/cron/jobs/job1"
/cron/jobs/job1
world

get：

package mainimport ( "context" "fmt" "go.etcd.io/etcd/clientv3" //"github.com/coreos/etcd/clientv3" "time")func main() { var ( config clientv3.Config client *clientv3.Client err error kv clientv3.KV getResp *clientv3.GetResponse ) //客户端配置 config = clientv3.Config{ Endpoints: []string{"0.0.0.0:2379"}, //集群列表 DialTimeout: 5 * time.Second, } //建立客户端 if client, err = clientv3.New(config); err != nil { fmt.Println(err) return } //用于读写etcd的键值对 kv = clientv3.NewKV(client) if getResp, err = kv.Get(context.TODO(), "/cron/jobs/job1"); err != nil { fmt.Println(err) } else { fmt.Println(getResp.Kvs) }}

[root@bogon etcd]# go run demo3.go
[key:"/cron/jobs/job1" create_revision:4 mod_revision:21 version:16 value:"world" ]
(create_revision：创建版本。mod_revision：修改版本。version：自从创建以来修改的次数。)

(敲with列出所有选项)

获取指定“目录”下的kvs：

package mainimport ( "context" "fmt" "go.etcd.io/etcd/clientv3" //"github.com/coreos/etcd/clientv3" "time")func main() { var ( config clientv3.Config client *clientv3.Client err error kv clientv3.KV getResp *clientv3.GetResponse ) //客户端配置 config = clientv3.Config{ Endpoints: []string{"0.0.0.0:2379"}, //集群列表 DialTimeout: 5 * time.Second, } //建立客户端 if client, err = clientv3.New(config); err != nil { fmt.Println(err) return } //用于读写etcd的键值对 kv = clientv3.NewKV(client) //读取/cron/jobs/为前缀的所有key if getResp, err = kv.Get(context.TODO(), "/cron/jobs/", clientv3.WithPrefix()); err != nil { fmt.Println(err) } else { //获取成功，我们遍历所有kvs fmt.Println(getResp.Kvs) }}

[root@bogon etcd]# go run demo4.go
[key:"/cron/jobs/job1" create_revision:4 mod_revision:21 version:16 value:"world" key:"/cron/jobs/job2" create_revision:5 mod_revision:6 version:2 value:"changed" ]

删除：

package mainimport ( "context" "fmt" "go.etcd.io/etcd/clientv3" "go.etcd.io/etcd/mvcc/mvccpb" //"github.com/coreos/etcd/clientv3" "time")func main() { var ( config clientv3.Config client *clientv3.Client err error kv clientv3.KV delResp *clientv3.DeleteResponse //idx int kvpair *mvccpb.KeyValue ) //客户端配置 config = clientv3.Config{ Endpoints: []string{"0.0.0.0:2379"}, //集群列表 DialTimeout: 5 * time.Second, } //建立客户端 if client, err = clientv3.New(config); err != nil { fmt.Println(err) return } //用于读写etcd的键值对 kv = clientv3.NewKV(client) //删除kv if delResp, err = kv.Delete(context.TODO(), "/cron/jobs/job2/", clientv3.WithPrevKV()); err != nil { fmt.Println(err) return } //被删除之前的value是什么 if len(delResp.PrevKvs) != 0 { //必须有clientv3.WithPrevKV()才能获取delResp.PrevKvs for _, kvpair = range delResp.PrevKvs { fmt.Println("删除了key:", string(kvpair.Key), " value:", string(kvpair.Value)) } }}

[root@bogon etcd]# go run demo5.go
删除了key: /cron/jobs/job2 value: changed
再次运行什么也不输出，因为已经删除了：
[root@bogon etcd]# go run demo5.go
[root@bogon etcd]#
如果要删除以/cron/jobs/job2/“目录”开头的所有kv，则将clientv3.WithPrevKV()改为：clientv3.WithPrefix()。
clientv3.WithFromKey()则是删除以此开头的所有kv(kv存储是有序的)。