/// <summary>
/// 分布式尝试锁
/// </summary>
/// <param name="info"></param>
/// <param name="action"></param>
/// <returns></returns>
public static LockResult TryLock(BaseDistributedLockInfo info, Action action)
{
try
{
if (info is RedisDistributedLockInfo)
{
var redisinfo = info as RedisDistributedLockInfo;
if (string.IsNullOrEmpty(DistributedLockConfig.DistributedLockRedisServers))
{
throw new DistributedLockException("请在web.config或app.config中配置DistributedLockRedisServers");
}
var redisserver = new RedisLoadBalance(DistributedLockConfig.GetDistributedLockRedisServerList()).ChooseRedisServer(info.DistributedLockKey);
using (var @lock = new RedisDistributedLockFromJava(redisserver, info.DistributedLockKey))
{
var islock = @lock.TryGetDistributedLock(info.GetLockTimeOut, info.TaskRunTimeOut);
if (islock == LockResult.Success)
{
action();
}
return(islock);
}
}
throw new DistributedLockException("info 参数传入错误");
}
catch (Exception exp)
{
XXF.Log.ErrorLog.Write(string.Format("分布式尝试锁错误,key:{0}", (info == null ? "" : info.DistributedLockKey.NullToEmpty())), exp);
throw exp;
}
}
public override void Dispose()
{
if (lockresult == LockResult.Success || lockresult == LockResult.LockSystemExceptionFailure)
{
try
{
long current = CurrentUnixTimeMillis();
using (var redisclient = DistributedLockConfig.GetRedisPoolClient(redisserver).GetClient())
{
var v = redisclient.Get(key);
if (v != null)
{
// 避免删除非自己获取得到的锁
if (current < BitConverter.ToInt64(v, 0))
{
redisclient.Del(key);
}
}
}
}
catch (Exception exp)
{
XXF.Log.ErrorLog.Write(string.Format("redis分布式尝试锁释放严重异常,redisserver:{0}", redisserver.NullToEmpty()), exp);
}
}
}
public override void Dispose()
{
try
{
using (var redisClient = DistributedLockConfig.GetRedisPoolClient(redisserver).GetClient())
{
redisClient.Remove(key);
}
}
catch (Exception exp)
{
XXF.Log.ErrorLog.Write(string.Format("redis分布式尝试锁释放严重异常,redisserver:{0}", redisserver.NullToEmpty()), exp);
}
}
public override LockResult TryGetDistributedLock(TimeSpan?getlockTimeOut, TimeSpan?taskrunTimeOut)
{
if (lockresult == LockResult.Success)
{
throw new DistributedLockException("检测到当前锁已获取");
}
_client = DistributedLockConfig.GetRedisPoolClient(redisserver).GetClient();
/*
* 阅读源码发现当其获取锁后,redis连接资源会一直占用,知道获取锁的资源释放后,连接才会跳出，可能会导致连接池资源的浪费。
*/
try
{
this._lock = new ServiceStack.Redis.RedisLock(_client, key, getlockTimeOut);
lockresult = LockResult.Success;
}
catch (Exception exp)
{
XXF.Log.ErrorLog.Write(string.Format("redis分布式尝试锁系统级别严重异常,redisserver:{0}", redisserver.NullToEmpty()), exp);
lockresult = LockResult.LockSystemExceptionFailure;
}
return(lockresult);
}
public override LockResult TryGetDistributedLock(TimeSpan?getlockTimeOut, TimeSpan?taskrunTimeOut)
{
if (lockresult == LockResult.Success)
{
throw new DistributedLockException("检测到当前锁已获取");
}
try
{
using (var redisClient = DistributedLockConfig.GetRedisPoolClient(redisserver).GetClient())
{
ExecExtensions.RetryUntilTrue(
() =>
{
//This pattern is taken from the redis command for SETNX http://redis.io/commands/setnx
//Calculate a unix time for when the lock should expire
TimeSpan realSpan = taskrunTimeOut ?? TimeSpan.FromMilliseconds(DistributedLockConfig.MaxLockTaskRunTime); //new TimeSpan(365, 0, 0, 0); //if nothing is passed in the timeout hold for a year
DateTime expireTime = DateTime.UtcNow.Add(realSpan);
string lockString = (expireTime.ToUnixTimeMs() + 1).ToString();
//Try to set the lock, if it does not exist this will succeed and the lock is obtained
var nx = redisClient.SetEntryIfNotExists(key, lockString);
if (nx)
{
lockresult = LockResult.Success;
return(true);
}
//If we've gotten here then a key for the lock is present. This could be because the lock is
//correctly acquired or it could be because a client that had acquired the lock crashed (or didn't release it properly).
//Therefore we need to get the value of the lock to see when it should expire
redisClient.Watch(key);
string lockExpireString = redisClient.Get <string>(key);
long lockExpireTime;
if (!long.TryParse(lockExpireString, out lockExpireTime))
{
redisClient.UnWatch(); // since the client is scoped externally
lockresult = LockResult.GetLockTimeOutFailure;
return(false);
}
//If the expire time is greater than the current time then we can't let the lock go yet
if (lockExpireTime > DateTime.UtcNow.ToUnixTimeMs())
{
redisClient.UnWatch(); // since the client is scoped externally
lockresult = LockResult.GetLockTimeOutFailure;
return(false);
}
//If the expire time is less than the current time then it wasn't released properly and we can attempt to
//acquire the lock. The above call to Watch(_lockKey) enrolled the key in monitoring, so if it changes
//before we call Commit() below, the Commit will fail and return false, which means that another thread
//was able to acquire the lock before we finished processing.
using (var trans = redisClient.CreateTransaction()) // we started the "Watch" above; this tx will succeed if the value has not moved
{
trans.QueueCommand(r => r.Set(key, lockString));
//return trans.Commit(); //returns false if Transaction failed
var t = trans.Commit();
if (t == false)
{
lockresult = LockResult.GetLockTimeOutFailure;
}
else
{
lockresult = LockResult.Success;
}
return(t);
}
},
getlockTimeOut
);
}
}
catch (Exception exp)
{
XXF.Log.ErrorLog.Write(string.Format("redis分布式尝试锁系统级别严重异常,redisserver:{0}", redisserver.NullToEmpty()), exp);
lockresult = LockResult.LockSystemExceptionFailure;
}
return(lockresult);
}
public override LockResult TryGetDistributedLock(TimeSpan?getlockTimeOut, TimeSpan?taskrunTimeOut)
{
if (lockresult == LockResult.Success)
{
throw new DistributedLockException("检测到当前锁已获取");
}
try
{
// 1. 通过SETNX试图获取一个lock
string @lock = key;
long taskexpiredMilliseconds = (taskrunTimeOut != null ? (long)taskrunTimeOut.Value.TotalMilliseconds : (long)DistributedLockConfig.MaxLockTaskRunTime);
long getlockexpiredMilliseconds = (getlockTimeOut != null ? (long)getlockTimeOut.Value.TotalMilliseconds : 0);
long hassleepMilliseconds = 0;
while (true)
{
using (var redisclient = DistributedLockConfig.GetRedisPoolClient(redisserver).GetClient())
{
long value = CurrentUnixTimeMillis() + taskexpiredMilliseconds + 1;
/*Java以前版本都是用SetNX,但是这种是无法设置超时时间的,不是很理解为什么,
* 可能是因为原来的redis命令比较少导致的？现在用Add不知道效果如何.
* 因对redis细节不了解，但个人怀疑若异常未释放锁经常发生，可能会导致内存逐步溢出*/
bool acquired = redisclient.Add <long>(@lock, value, TimeSpan.FromMilliseconds(taskexpiredMilliseconds + DistributedLockConfig.TaskLockDelayCleepUpTime));
//SETNX成功，则成功获取一个锁
if (acquired == true)
{
lockresult = LockResult.Success;
}
//SETNX失败，说明锁仍然被其他对象保持，检查其是否已经超时
else
{
var oldValueBytes = redisclient.Get(@lock);
//超时
if (oldValueBytes != null && BitConverter.ToInt64(oldValueBytes, 0) < CurrentUnixTimeMillis())
{
/*此处虽然重设并获取锁,但是超时时间可能被覆盖,故重设超时时间;若有进程一直在尝试获取锁，那么锁存活时间应该被延迟*/
var getValueBytes = redisclient.GetSet(@lock, BitConverter.GetBytes(value));
var o1 = redisclient.ExpireEntryIn(@lock, TimeSpan.FromMilliseconds(taskexpiredMilliseconds + DistributedLockConfig.TaskLockDelayCleepUpTime));//这里如果程序异常终止，依然会有部分锁未释放的情况。
// 获取锁成功
if (getValueBytes == oldValueBytes)
{
lockresult = LockResult.Success;
}
// 已被其他进程捷足先登了
else
{
lockresult = LockResult.GetLockTimeOutFailure;
}
}
//未超时，则直接返回失败
else
{
lockresult = LockResult.GetLockTimeOutFailure;
}
}
}
//成功拿到锁
if (lockresult == LockResult.Success)
{
break;
}
//获取锁超时
if (hassleepMilliseconds >= getlockexpiredMilliseconds)
{
lockresult = LockResult.GetLockTimeOutFailure;
break;
}
//继续等待
System.Threading.Thread.Sleep(DistributedLockConfig.GetLockFailSleepTime);
hassleepMilliseconds += DistributedLockConfig.GetLockFailSleepTime;
}
}
catch (Exception exp)
{
XXF.Log.ErrorLog.Write(string.Format("redis分布式尝试锁系统级别严重异常,redisserver:{0}", redisserver.NullToEmpty()), exp);
lockresult = LockResult.LockSystemExceptionFailure;
}
return(lockresult);
}