Implementing an Async Singleton Pattern in .NET 6 - Issues with Multiple Requests
I'm refactoring my project and I'm trying to figure out I'm stuck on something that should probably be simple... I'm performance testing and I'm trying to implement an async singleton pattern in a .NET 6 application, but I'm running into issues when multiple requests try to access the singleton instance simultaneously. I followed a pattern using `Lazy<T>` to ensure thread safety, but I'm still facing `System.InvalidOperationException` occasionally, which states 'The instance is not initialized'. Here's the code snippet I'm using: ```csharp public class AsyncSingleton { private static readonly Lazy<Task<AsyncSingleton>> _instance = new Lazy<Task<AsyncSingleton>>(InitializeAsync); private AsyncSingleton() { } public static Task<AsyncSingleton> Instance => _instance.Value; private static async Task<AsyncSingleton> InitializeAsync() { // Simulate an async initialization process await Task.Delay(1000); return new AsyncSingleton(); } } ``` When I call `AsyncSingleton.Instance` from multiple threads, I sometimes get the exception when accessing properties of the singleton. I even tried wrapping the access in a try-catch block, but that didn’t help much as it’s still an unhandled exception that breaks my application. I've also ensured that no start-up logic is calling `Instance` before the application is ready. Is there a recommended way to properly implement an async singleton pattern in .NET 6 that addresses this issue? I've looked at various sources, but they don't cover the nuances of async initialization very well. Any suggestions or insights would be greatly appreciated! I'm using C# stable in this project. What's the correct way to implement this? Could someone point me to the right documentation? I've been using C# for about a year now. Could this be a known issue? I'm working with C# in a Docker container on Ubuntu 22.04. What are your experiences with this?