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| package main
import (
"context"
"fmt"
"go.etcd.io/etcd/clientv3"
"go.etcd.io/etcd/mvcc/mvccpb"
"log"
"path"
"strconv"
"sync"
)
type myMutex struct {
client *clientv3.Client
leaseId clientv3.LeaseID
pfx string
myKey string
myRev int64
}
func newMyMutex(cli *clientv3.Client, pfx string) (*myMutex, error) {
resp, err := cli.Grant(context.TODO(), 15)
if err != nil {
return nil, err
}
if _, err := cli.KeepAlive(context.TODO(), resp.ID); err != nil {
return nil, err
}
mu := &myMutex{
client: cli,
leaseId: resp.ID,
pfx: pfx,
myKey: path.Join(pfx, strconv.FormatInt(int64(resp.ID), 16)),
myRev: -1,
}
return mu, nil
}
func (mu *myMutex) Close() error {
ctx, cancel := context.WithCancel(context.TODO())
_, err := mu.client.Revoke(ctx, mu.leaseId)
cancel()
return err
}
func (mu *myMutex) UnLock(ctx context.Context) error {
_, err := mu.client.Delete(ctx, mu.myKey)
return err
}
func (mu *myMutex) Lock(ctx context.Context) error {
cmp := clientv3.Compare(clientv3.CreateRevision(mu.myKey), "=", 0)
put := clientv3.OpPut(mu.myKey, "", clientv3.WithLease(mu.leaseId))
get := clientv3.OpGet(mu.myKey)
getOwner := clientv3.OpGet(mu.pfx, clientv3.WithFirstCreate()...)
resp, err := mu.client.Txn(ctx).If(cmp).Then(put, getOwner).Else(get, getOwner).Commit()
if err != nil {
return err
}
mu.myRev = resp.Header.Revision
if !resp.Succeeded {
mu.myRev = resp.Responses[0].GetResponseRange().Kvs[0].CreateRevision
}
ownerRev := resp.Responses[1].GetResponseRange().Kvs[0].CreateRevision
if ownerRev == mu.myRev {
return nil
}
getOps := append(clientv3.WithLastCreate(), clientv3.WithMaxCreateRev(mu.myRev-1))
for {
resp, err := mu.client.Get(ctx, mu.pfx, getOps...)
if err != nil {
return err
}
if len(resp.Kvs) == 0 {
break
}
wch := mu.client.Watch(ctx, string(resp.Kvs[0].Key), clientv3.WithRev(resp.Header.Revision))
for wr := range wch {
isBreak := false
for _, ev := range wr.Events {
if ev.Type == mvccpb.DELETE {
isBreak = true
break
}
}
if isBreak {
break
}
}
}
return nil
}
func main() {
var cnt int64
var wg sync.WaitGroup
endpoints := []string{"127.0.0.1:2379"}
for i := 0; i < 10; i++ {
wg.Add(1)
go func() {
cli, err := clientv3.New(clientv3.Config{Endpoints: endpoints})
if err != nil {
log.Fatal(err)
}
defer cli.Close()
mu, err := newMyMutex(cli, "/my_mutex")
if err != nil {
log.Fatal(err)
}
defer mu.Close()
mu.Lock(context.TODO())
defer mu.UnLock(context.TODO())
for k := 0; k < 100000; k++ {
cnt = cnt + 1
}
wg.Done()
}()
}
wg.Wait()
fmt.Println(cnt)
}
|
