基于redis的分布式锁
上于公司业务上需要实现分布式锁，在网上找了一些实现的案例，最终打算采用基于redis的分布式锁方案，不多废话，上代码核心类
1 using System;
2 using System.Diagnostics;
3 using System.Text;
4 using System.Threading;
5 using BookSleeve;
6
7 namespace ViewAlloc.Threading
8 {
9 public class RedisBillLockHandler
10 {
11 private const int DEFAULT_SINGLE_EXPIRE_TIME = 10;
12 private static readonly DateTime DEFAULT_DATETIME = new DateTime(1970, 1, 1);
13 private const int DEFAULT_DB = 0;
14
15 private readonly RedisConnection client;
16
17 ///
18 /// 构造
19 ///
20 ///
21 public RedisBillLockHandler(RedisConnection client)
22 {
23 this.client = client;
24 }
25
26 ///
27 /// 获取锁
28 /// 如果锁可用立即返回true,否则返回false
29 ///
30 ///
31 ///
32 public bool TryLock(String key)
33 {
34 return TryLock(key, 0L);
35 }
36
37 ///
38 /// 锁在给定的等待时间内空闲，则获取锁成功 返回true， 否则返回false
39 ///
40 ///
41 ///
42 ///
43 public bool TryLock(String key, long timeout)
44 {
45 try
46 {
47 Stopwatch watch = Stopwatch.StartNew();
48 do
49 {
50 long tt = (long)(DateTime.Now - DEFAULT_DATETIME).TotalSeconds;
51 long timestamp = tt + DEFAULT_SINGLE_EXPIRE_TIME + 1;
52
53 var tran = client.CreateTransaction();
54 var taskSetIfNotExists = tran.Strings.SetIfNotExists(DEFAULT_DB, key, Encoding.UTF8.GetBytes(timestamp.ToString()));
55 var taskGet = tran.Strings.Get(DEFAULT_DB, key);
56 tran.Execute().Wait();
57 tran.Dispose();
58 if (taskSetIfNotExists.Result == true)
59 {
60 return true;
61 }
62 else
63 {
64
65 long ex = long.Parse(Encoding.UTF8.GetString(taskGet.Result));
66 if (tt > ex)
67 {
68 var taskGetSet = client.Strings.GetSet(DEFAULT_DB, key, Encoding.UTF8.GetBytes(timestamp.ToString()));
69 long old = long.Parse(Encoding.UTF8.GetString(taskGetSet.Result));
70
71 if (ex == old)
72 {
73 return true;
74 }
75 }
76 }
77 if (timeout == 0)
78 {
79 break;
80 }
81 Thread.Sleep(300);
82 } while (watch.ElapsedMilliseconds < timeout * 1000);
83 return false;
84 }
85 catch (Exception exc)
86 {
87 throw new RedisBillLockException(exc.Message, exc);
88 }
89 }
90
91 ///
92 /// 如果锁空闲立即返回
93 /// 获取失败一直等待
94 ///
95 ///
96 public void Lock(String key)
97 {
98 try
99 {
100 do
101 {
102 long tt = (long)(DateTime.Now - DEFAULT_DATETIME).TotalSeconds;
103 long timestamp = tt + DEFAULT_SINGLE_EXPIRE_TIME + 1;
104
105 var tran = client.CreateTransaction();
106 var taskSetIfNotExists = tran.Strings.SetIfNotExists(DEFAULT_DB, key, Encoding.UTF8.GetBytes(timestamp.ToString()));
107 var taskGet = tran.Strings.Get(DEFAULT_DB, key);
108 tran.Execute().Wait();
109 tran.Dispose();
110 if (taskSetIfNotExists.Result == true)
111 {
112 break;
113 }
114 else
115 {
116
117 long ex = long.Parse(Encoding.UTF8.GetString(taskGet.Result));
118 if (tt > ex)
119 {
120 var taskGetSet = client.Strings.GetSet(DEFAULT_DB, key, Encoding.UTF8.GetBytes(timestamp.ToString()));
121 long old = long.Parse(Encoding.UTF8.GetString(taskGetSet.Result));
122 if (ex == old)
123 {
124 break;
125 }
126 }
127 }
128
129 Thread.Sleep(300);
130 } while (true);
131 }
132 catch (Exception exc)
133 {
134 throw new RedisBillLockException(exc.Message, exc);
135 }
136 }
137
138 ///
139 /// 释放锁
140 ///
141 ///
142 public void UnLock(String key)
143 {
144 try
145 {
146 long tt = (long)(DateTime.Now - DEFAULT_DATETIME).TotalSeconds;
147 var taskGet = client.Strings.Get(DEFAULT_DB, key);
148 long ex = long.Parse(Encoding.UTF8.GetString(taskGet.Result));
149 if (tt < ex)
150 {
151 var taskRemove = client.Keys.Remove(DEFAULT_DB, key);
152 taskRemove.Wait();
153 }
154 }
155 catch (Exception exc)
156 {
157 throw new RedisBillLockException(exc.Message, exc);
158 }
159 }
160 }
161
162 }
为了不破坏原有的代码逻辑我又加了下面两个类
using System;
namespace ViewAlloc.Threading
{
///
/// 分布式锁属性
///
public class RedisBillLockAttribute : Attribute
{
public string Scheme { set; get; }
public string Key { set; get; }
public RedisBillLockAttribute(string scheme, string key)
{
this.Scheme = scheme;
this.Key = key;
}
}
}
using System;
using System.Reflection;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Messaging;
namespace ViewAlloc.Threading
{
///
/// 装饰类，不需要对每一个类进行封装了，性能可能会有一细细的影响
///
public class RedisBillLockWrapper
{
public static T Wrap(T target) where T : MarshalByRefObject
{
return new MyProxy(typeof(T), target).GetTransparentProxy() as T;
}
private class MyProxy : System.Runtime.Remoting.Proxies.RealProxy
{
public MyProxy(Type t, MarshalByRefObject target)
: base(t)
{
this.target = target;
}
public override IMessage Invoke(IMessage msg)
{
MethodBase method = (msg as IMethodMessage).MethodBase;
object[] atts = method.GetCustomAttributes(typeof(RedisBillLockAttribute), false);
bool locking = atts.Length == 1;
IMessage result = null;
if (locking)
{
RedisBillLockAttribute redisBillLockAttribute = atts as RedisBillLockAttribute;
BookSleeve.RedisConnection client = new BookSleeve.RedisConnection(redisBillLockAttribute.Scheme);
client.Open();
try
{
RedisBillLockHandler lockHandler = new RedisBillLockHandler(client);
lockHandler.Lock(redisBillLockAttribute.Key);
try
{
result = RemotingServices.ExecuteMessage(target, msg as IMethodCallMessage);
}
finally
{
lockHandler.UnLock(redisBillLockAttribute.Key);
}
}
finally
{
client.Close(false);
}
}
else
{
result = RemotingServices.ExecuteMessage(target, msg as IMethodCallMessage);
}
return result;
}
private MarshalByRefObject target;
}
}
}
原先的业务逻辑类
class TestLock
{
public void Run()
{
Console.WriteLine("{0:yyyyMMddHHmmssfff}获取了锁", DateTime.Now);
Thread.Sleep(1000);
}
}
修改后的
class TestLock : MarshalByRefObject
{
public void Run()
{
Console.WriteLine("{0:yyyyMMddHHmmssfff}获取了锁", DateTime.Now);
Thread.Sleep(1000);
}
}
调用
TestLock testLock = RedisBillLockWrapper.Wrap(new TestLock());
testLock.Run();
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