I have a .net core razor app that has a special use case where I need to have a global counter that will be incremented by every request, and yet it should remain thread-safe.

Also at web application load, this counter will be read from a database using entity framework.

I don't think that static variables are threadsafe for this scenario (since it can be read by a request then be modified after another request read its previous value)

So I was wondering if a locking mechanism is needed, or should a concurrent dictionary with a Lazy be used?

public static void PrintValueLazy(string valueToPrint)
{
var valueFound = _lazyDictionary.GetOrAdd("key",
            x => new Lazy<string>(
                () =>
                    {
                        Interlocked.Increment(ref _runCount);
                        Thread.Sleep(100);
                        return valueToPrint;
                    }));
Console.WriteLine(valueFound.Value);
}

I have a .net core razor app that has a special use case where I need to have a global counter that will be incremented by every request, and yet it should remain thread-safe.

Also at web application load, this counter will be read from a database using entity framework.

I don't think that static variables are threadsafe for this scenario (since it can be read by a request then be modified after another request read its previous value).

So I was wondering if a locking mechanism is needed, or should a concurrent dictionary with a Lazy<T> be used?

public static void PrintValueLazy(string valueToPrint)
{
var valueFound = _lazyDictionary.GetOrAdd("key",
            x => new Lazy<string>(
                () =>
                    {
                        Interlocked.Increment(ref _runCount);
                        Thread.Sleep(100);
                        return valueToPrint;
                    }));
Console.WriteLine(valueFound.Value);
}