Exclusive distributed lock library for C#/.NET using MongoDB
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$ dotnet add package DistributedLock.MongoReadme
DistributedLock.Mongo: Exclusive Distributed Locking for .NET
DistributedLock.Mongo is a class library available on NuGet that enables exclusive distributed locking mechanisms for applications using .NET and MongoDB. It facilitates safe coordination of operations across different system components by managing access to shared resources. For more details or to download the library, visit the NuGet page.
Usage
using DistributedLock.Mongo;
using MongoDB.Driver;
using System;
const string connectionString = "mongodb://localhost:27017/"; // MongoDB connection string
var client = new MongoClient(connectionString);
var database = client.GetDatabase("sample-db");
// This is a regular collection, not a capped one.
var locks = database.GetCollection<LockAcquire<Guid>>("locks");
// Ensure this collection is capped. Refer to MongoDB's documentation on capped collections:
// https://docs.mongodb.com/manual/core/capped-collections/
// The capped collection size should be sufficient to accommodate all active locks. Each ReleaseSignal is estimated at 32 bytes,
// so approximately 3 megabytes will be required to handle up to 100,000 simultaneous locks.
var signals = database.GetCollection<ReleaseSignal>("signals");
// The 'lockId' variable serves as the identifier for your distributed lock. It can be a Guid, string, int, or any other suitable type
// depending on your application's requirements and the characteristics of the locks being implemented.
var lockId = Guid.Parse("BF431614-4FB0-4489-84AA-D3EFEEF6BE7E");
var mongoLock = new MongoLock<Guid>(locks, signals, lockId);
// Attempt to acquire an exclusive lock. The lifetime for the created lock is 30 seconds.
await using (var acquire = await mongoLock.AcquireAsync(TimeSpan.FromSeconds(30), TimeSpan.FromSeconds(10)))
{
if (acquire.Acquired)
{
// Critical section: This block cannot be executed by more than one thread on any server at a time.
// ...
// ...
}
else
{
// Timeout occurred! It's possible another thread has not released the lock yet.
// Consider retrying or handling this scenario with an exception.
}
}
// Alternatively, you can handle the lock using a try...finally block as shown below:
var anotherAcquire = await mongoLock.AcquireAsync(TimeSpan.FromSeconds(30), TimeSpan.FromSeconds(10));
try
{
// if (anotherAcquire.Acquired)
// { ... }
}
finally
{
// if (acquire.Acquired) no need to do it manually
await mongoLock.ReleaseAsync(anotherAcquire);
}