c# 理解csredis库实现分布式锁的详细流程

using CSRedis;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;

namespace CsRedis.Helper
{
    /// <summary>
    ///  基于csredis的简单封装
    /// </summary>
    public class CsRedisManager
    {
       
        private ConcurrentDictionary<string, CSRedisClient> _serviceNameWithClient;
      
        /// <summary>
        ///  初始化
        /// </summary>
        public void Init()
        {
            _serviceNameWithClient = new ConcurrentDictionary<string, CSRedisClient>();
        }
        ///  获取业务redis服务
        /// <param name="serviceName"></param>
        /// <returns></returns>
        public CSRedisClient GetRedisClient(string serviceName)
            CSRedisClient result = null;
            _serviceNameWithClient.TryGetValue(serviceName,out result);
            return result;
        ///  添加redis服务
        /// <param name="connectStr"></param>
        public bool AddRedisClient(string serviceName,string connectStr)
            CSRedisClient cSRedisClient = new CSRedisClient(connectStr);
            return _serviceNameWithClient.TryAdd(serviceName, cSRedisClient);
        ///  设置字符串型kv 
        /// <param name="key">key</param>
        /// <param name="value">value</param>
        /// <param name="expireSecond">过期时间（秒）</param>
        /// <returns>是否成功</returns>
        public bool Set(string serviceName,string key,string value,int expireSecond=-1)
            var redisClient = GetRedisClient(serviceName);
            GetExceptionOfClient(redisClient);
            
            return redisClient.Set(key, value, expireSecond);
           
        ///  获取相应key的值
        /// <param name="key"></param>
        public string Get(string serviceName, string key)
            return redisClient.Get(key);
        ///  如果不存在则执行，存在则忽略
        /// <param name="value"></param>
        public bool SetNx(string serviceName, string key, string value)
            var res = redisClient.SetNx(key, value);
            return res;
        ///  带过期时间的setNx
        /// <param name="seconds"></param>
        public bool SetNx(string serviceName, string key, string value, int millSeconds = -1)
            var res = Set(serviceName, key, value, RedisExistence.Nx, millSeconds);
        ///  带过期时间的SetXx
        public bool SetXx(string serviceName, string key, string value, int millSeconds = -1)
            var res = Set(serviceName, key, value, RedisExistence.Xx, millSeconds);
        ///  带参数set
        /// <param name="existence"></param>
        public bool Set(string serviceName, string key, string value, RedisExistence existence, int millSeconds = -1)
            var res = redisClient.Set(key, value, millSeconds, existence);
        ///  设置生存时间
        public bool Expire(string serviceName, string key, int seconds)
            return redisClient.Expire(key, seconds);
        ///  获取剩余的生存时间（秒）
        public long Ttl(string serviceName, string key)
            return redisClient.Ttl(key);
        ///  删除del
        public long Del(string serviceName,params string[] keys)
            return redisClient.Del(keys);
        ///  执行脚本
        /// <param name="script"></param>
        /// <param name="args"></param>
        public object Eval(string serviceName, string script,string key,params object[] args)
            var res = redisClient.Eval(script, key,args);
        ///  添加共享锁
        public bool AddLock(string serviceName, string key,string token, int millSeconds = -1)
            var valRes = SetNx(serviceName, key, token, millSeconds);
            return valRes;
        ///  删除共享锁
        public bool ReleaseLock(string serviceName, string key,string token)
            var script = GetReleaseLockScript();
            var res = redisClient.Eval(script, key, token);
            if (0== (long)res)
            {
                return false;
            }
            return true;
        ///  获取键值
        /// <param name="pattern"></param>
        public string[] Keys(string serviceName, string pattern)
            var res = redisClient.Keys(pattern);
        ///  获取client发生异常
        /// <param name="client"></param>
        private void GetExceptionOfClient(CSRedisClient client)
            if (client == null)
                throw new Exception("无有效的redis服务");
        ///  lua脚本删除共享锁
        ///  解决在A申请锁 xxkey  过期的瞬间，B 申请锁xxkey,
        ///  此时恰好A执行到释放xxkey从而引起的异常释放
        private static  string GetReleaseLockScript()
            return "if redis.call(\"get\",KEYS[1]) == ARGV[1] \nthen\nreturn redis.call(\"del\", KEYS[1])\nelse\nreturn 0\nend";
        
    }
    
}

if redis.call("get",KEYS[1]) == ARGV[1]
then
    return redis.call("del",KEYS[1])
else
    return 0
end

using CsRedis.Helper;
using NUnit.Framework;

namespace TestProject
{
    public class Tests
    {
        [SetUp]
        public void Setup()
        {
        }
        [Test]
        public void Test1()
            CsRedisManager csRedisManager = new CsRedisManager();
            csRedisManager.Init();
            csRedisManager.AddRedisClient("TEST", "127.0.0.1:6379,passWord=123456, connectTimeout =1000,connectRetry=1,syncTimeout=10000,defaultDatabase=0");
            //csRedisManager.AddRedisClient("PRODUCT", "127.0.0.1:6379,password=123456, connectTimeout =1000,connectRetry=1,syncTimeout=10000,defaultDatabase=1");
            
            var token = "123";
            var lockKey = "LOCKKEY1";
            csRedisManager.AddLock("TEST", lockKey,token,20 * 1000);
            csRedisManager.ReleaseLock("TEST", lockKey, token);
    }
}