golang redis实现分布式锁

package main

import (
	"context"
	"fmt"
	"time"

	"github.com/go-redis/redis/v8"
)

func main() {
	redisCli := redis.NewClient(&redis.Options{
		Addr:     "127.0.0.1:6379",
		Password: "123456",
		DB:       0,
	})
	redisLock := NewRedisLock("test_key1", "test_value1", 1*time.Minute, redisCli)
	locked, err := redisLock.TryLock()
	fmt.Printf("locked:%v,err:%v\n", locked, err)
}

// RedisLock redis实现的分布式锁
type RedisLock struct {
	key        string
	value      string // 唯一标识,一般使用uuid
	expiration time.Duration
	redisCli   *redis.Client
}

func NewRedisLock(key, value string, expiration time.Duration, cli *redis.Client) *RedisLock {
	if key == "" || value == "" || cli == nil {
		return nil
	}
	return &RedisLock{
		key:        key,
		value:      value,
		expiration: expiration,
		redisCli:   cli,
	}
}

// Lock 添加分布式锁,expiration过期时间,小于等于0,不过期,需要通过 UnLock方法释放锁
func (rl *RedisLock) Lock() (bool, error) {
	result, err := rl.redisCli.SetNX(context.Background(), rl.key, rl.value, rl.expiration).Result()
	if err != nil {
		return false, err
	}

	return result, nil
}

// TryLock 加锁重试五次
func (rl *RedisLock) TryLock() (bool, error) {
	var locked bool
	var err error
	for index := 0; index < 5; index++ {
		locked, err = rl.Lock()
		if locked && err == nil {
			return locked, err
		}
		time.Sleep(50 * time.Millisecond)
	}

	return locked, nil
}

func (rl *RedisLock) UnLock() (bool, error) {
	script := redis.NewScript(`
	if redis.call("get", KEYS[1]) == ARGV[1] then
		return redis.call("del", KEYS[1])
	else
		return 0
	end
	`)

	result, err := script.Run(context.Background(), rl.redisCli, []string{rl.key}, rl.value).Int64()
	if err != nil {
		return false, err
	}

	return result > 0, nil
}

// RefreshLock 存在则更新过期时间,不存在则创建key
func (rl *RedisLock) RefreshLock() (bool, error) {
	script := redis.NewScript(`
	local val = redis.call("GET", KEYS[1])
	if not val then
		redis.call("setex", KEYS[1], ARGV[2], ARGV[1])
		return 2
	elseif val == ARGV[1] then
		return redis.call("expire", KEYS[1], ARGV[2])
	else
		return 0
	end
	`)

	result, err := script.Run(context.Background(), rl.redisCli, []string{rl.key}, rl.value, rl.expiration/time.Second).Int64()
	if err != nil {
		return false, err
	}

	return result > 0, nil
}