How to create a generic method in .NET to capture latency (elapsed times) of different methods with different signatures in my application?

Question

I am trying to trace metrics for .NET core application and libraries referenced. Metrics like: latency, throughput, count, size, ..etc.

For instance, say I am implementing latency metric, I will have to surround each method I want to calculate latency for as follows:

    var sw = Stopwatch.StartNew();
    var result = MyFunction(input1, input2, input3);
    sw.Stop();
    
    // set latency out
    latency = sw.ElapsedMilliseconds;
    return result;

I am trying to see if there is a cleaner way in C#. I thought of passing a delegate method and defining a function like this to avoid duplication of Stopwatch.StartNew() and sw.Stop()

 public static TResult CollectLatency<T, U, V,TResult>(Func<T, U, V, TResult> func, out long latency, T input1, U input2, V input3)
        {
            var sw = Stopwatch.StartNew();
            var result = func(input1, input2, input3);
            sw.Stop();
            
            // set latency out
            latency = sw.ElapsedMilliseconds;
            return result;
        }

but then I will have to define overloads of this method with different number of inputs depending on all the methods I want to measure latency against.

One solution I thought of was to have only one input and have all my methods to be measured only take one parameter ( a class reference type including all parameters). However, that is not an option since there are existing external consumers to these methods and will break them during upgrade.

Is there another solution I can explore?

John Wu · Accepted Answer · 2020-09-26T00:00:50.187

2

You could pass parameters as closed variables, which eliminates the need to implement overloads for each type of parameters.

public static long CollectLatency(Action action)
{
    var sw = Stopwatch.StartNew();
    action();
    sw.Stop();
    return sw.ElapsedMilliseconds;
}

Then you'd call it like tis:

var latency = CollectLatency( () => MyFunction(input1, input2, input3) );

If you actually need the result and not just the latency, you can also collect that in a closed variable.

SomeType result;
var latency = CollectLatency( () => result = MyFunction(input1, input2, input3) );

edited Sep 26 '20 at 00:00

answered Sep 25 '20 at 23:42

John Wu

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but Action encapsulated method with no return type. So the line above ```var result = action()``` will not compile – Saher Ahwal Sep 25 '20 at 23:59
Thanks John. so even though now you don't have the action result stored, how does the second example work? – Saher Ahwal Sep 26 '20 at 00:02
1

Part of the action is to set `result`. The action doesn't return anything. It just writes to a variable that the caller can then read. – John Wu Sep 26 '20 at 00:04
What if the action I have was async and I need to await? do I replace the Action with Task? – Saher Ahwal Sep 26 '20 at 19:50
1

You'd replace it with `Func` – John Wu Sep 27 '20 at 07:22

How to create a generic method in .NET to capture latency (elapsed times) of different methods with different signatures in my application?

1 Answers1