.NET कोर में रेडिस डिस्ट्रिब्यूटेड लॉक लागू करना

परिचय

लॉक क्यों वितरित किया गया?

public void SomeMethod() 
{ 
 // Do something... 
 lock (obj) 
 { 
 // Do .... 
 } 
 // Do something... 
}

लॉक कैसे बनाएं?

/// <summary> 
/// The lazy connection. 
/// </summary> 
private static Lazy<ConnectionMultiplexer> lazyConnection = new Lazy<ConnectionMultiplexer>(() => 
{ 
 ConfigurationOptions configuration = new ConfigurationOptions 
 { 
 AbortOnConnectFail = false, 
 ConnectTimeout = 5000, 
 }; 
 configuration.EndPoints.Add("localhost", 6379); 
 return ConnectionMultiplexer.Connect(configuration.ToString()); 
}); 
/// <summary> 
/// Gets the connection. 
/// </summary> 
/// <value>The connection.</value> 
public static ConnectionMultiplexer Connection => lazyConnection.Value;

SET resource_name unique_value NX PX duration

/// <summary> 
/// Acquires the lock. 
/// </summary> 
/// <returns><c>true</c>, if lock was acquired, <c>false</c> otherwise.</returns> 
/// <param name="key">Key.</param> 
/// <param name="value">Value.</param> 
/// <param name="expiration">Expiration.</param> 
static bool AcquireLock(string key, string value, TimeSpan expiration) 
{ 
 bool flag = false; 
 try 
 { 
 flag = Connection.GetDatabase().StringSet(key, value, expiration, When.NotExists); 
 } 
 catch (Exception ex) 
 { 
 Console.WriteLine($"Acquire lock fail...{ex.Message}"); 
 flag = true; 
 } 
 return flag; 
} 

static void Main(string[] args) 
{ 
 string lockKey = "lock:eat"; 
 TimeSpan expiration = TimeSpan.FromSeconds(5); 
 // 5 person eat something... 
 Parallel.For(0, 5, x => 
 { 
 string person = $"person:{x}"; 
 bool isLocked = AcquireLock(lockKey, person, expiration); 
 if (isLocked) 
 { 
 Console.WriteLine($"{person} begin eat food (with lock) at {DateTimeOffset.Now.ToUnixTimeMilliseconds()}."); 
 } 
 else 
 { 
 Console.WriteLine($"{person} cannot eat food due to not getting the lock."); 
 } 
 }); 
 Console.WriteLine("end"); 
 Console.Read(); 
} 

लॉक कैसे खोलें?

/// <summary> 
/// Releases the lock. 
/// </summary> 
/// <returns><c>true</c>, if lock was released, <c>false</c> otherwise.</returns> 
/// <param name="key">Key.</param> 
/// <param name="value">Value.</param> 
static bool ReleaseLock(string key, string value) 
{ 
 string lua_script = @" 
 if (redis.call('GET', KEYS[1]) == ARGV[1]) then 
 redis.call('DEL', KEYS[1]) 
 return true 
 else 
 return false 
 end 
 "; 
 try 
 { 
 var res = Connection.GetDatabase().ScriptEvaluate(lua_script, 
 new RedisKey[] { key }, 
 new RedisValue[] { value }); 
 return (bool)res; 
 } 
 catch (Exception ex) 
 { 
 Console.WriteLine($"ReleaseLock lock fail...{ex.Message}"); 
 return false; 
 } 
} 

Parallel.For(0, 5, x => 
{ 
 string person = $"person:{x}"; 
 var val = 0; 
 bool isLocked = AcquireLock(lockKey, person, expiration); 
 while (!isLocked && val <= 5000) 
 { 
 val += 250; 
 System.Threading.Thread.Sleep(250); 
 isLocked = AcquireLock(lockKey, person, expiration); 
 } 
 if (isLocked) 
 { 
 Console.WriteLine($"{person} begin eat food (with lock) at {DateTimeOffset.Now.ToUnixTimeMilliseconds()}."); 
 if (new Random().NextDouble() < 0.6) 
 { 
 Console.WriteLine($"{person} release lock {ReleaseLock(lockKey, person)} {DateTimeOffset.Now.ToUnixTimeMilliseconds()}"); 
 } 
 else 
 { 
 Console.WriteLine($"{person} do not release lock ...."); 
 } 
 } 
 else 
 { 
 Console.WriteLine($"{person} begin eat food (without lock) at {DateTimeOffset.Now.ToUnixTimeMilliseconds()}."); 
 } 
}); 

• RedisLockDemo

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