1. 基于redis 的 setnx

package main

import (
    "fmt"
    "sync"
    "time"

    "github.com/go-redis/redis"
)

func incr() {
    client := redis.NewClient(&redis.Options{
        Addr:     "127.0.0.1:6379",
        Password: "root",
        DB:       0,
    })

    var lockKey = "counter_lock"
    var counterKey = "counter"

    resp := client.SetNX(lockKey, 1, time.Second*5)
    ok, err := resp.Result()
    if err != nil || !ok {
        fmt.Println(err, "lock result: ", ok)
        return
    }

    getResp := client.Get(counterKey)
    cntValue, err := getResp.Int64()
    if err == nil || err == redis.Nil {
        cntValue++
        resp := client.Set(counterKey, cntValue, 0)
        _, err := resp.Result()
        if err != nil {
            println("set value error!")
        }
    }
    println("current counter is ", cntValue)

    delResp := client.Del(lockKey)
    unlockSuccess, err := delResp.Result()
    if err == nil && unlockSuccess > 0 {
        println("unlock  success!")
    } else {
        println("unlock failed", err)
    }
}

func main() {
    var wg sync.WaitGroup
    for i := 0; i < 10; i++ {
        wg.Add(1)
        go func() {
            defer wg.Done()
            incr()
        }()
    }
    wg.Wait()
}

2. 基于ZooKeeper

package main

import (
    "time"

    "github.com/samuel/go-zookeeper/zk"
)

func main() {
    c, _, err := zk.Connect([]string{"127.0.0.1"}, time.Second)
    if err != nil {
        panic(err)
    }
    l := zk.NewLock(c, "/lock", zk.WorldACL(zk.PermAll))
    err = l.Lock()
    if err != nil {
        panic(err)
    }
    println("lock succ, do your business login")

    time.Sleep(time.Second * 5)
    l.Unlock()
    println("unlock succ, finish business logic")
}

3. 基于etcd

package main

import (
    "log"

    "github.com/zieckey/etcdsync"
)

func main() {
    m, err := etcdsync.New("/mylock", 10, []string{"http://127.0.0.1:2379"})
    if m == nil || err != nil {
        panic(err)
    }
    err = m.Lock()
    if err != nil {
        log.Printf("etcdsync.lock failed")
    } else {
        log.Printf("etcd sync.lock succ")
    }

    log.Printf("get the lock, do something here.")

    err = m.Unlock()
    if err != nil {
        log.Printf("etcdsync.unlock failed")
    } else {
        log.Printf("etcdsync unlock succ")
    }

    log.Printf("unlock the lock, do something here.")
}