ArgusLogs.DataAnnotation — Custom interceptors

Section 4 of 4 ArgusLogs.DataAnnotation

Custom interceptors

If you need custom behavior on method boundaries (performance profiling, access control, parameter validation, or auditing), create your own attribute by inheriting from OnMethodBoundaryAspect.

Aspect lifecycle hooks

OnEntry(MethodExecutionArgs args) — Before the method body runs. Ideal for timers, validating inputs, or security checks. Setting args.IsBlocked = true blocks the target method entirely.
OnSuccess(MethodExecutionArgs args) — After successful completion. Read the return value via args.ReturnValue.
OnException(MethodExecutionArgs args) — If the method throws. Access the exception via args.Exception.
OnExit(MethodExecutionArgs args) — Always on exit, success or failure (like finally).

MethodExecutionArgs

TypeName / MethodName — Declaring class and name of the intercepted method.
Instance — Target object instance (null if static).
Arguments — Runtime parameters in declaration order.
ParameterNames — Names corresponding to Arguments.
ReturnValue — Available during OnSuccess.
Exception — Available during OnException.
Timer — Internal Stopwatch; start/stop with ForceStartTimer() and ForceStopTimer().

Example: custom performance profiler

TrackPerformanceAttribute.cs

using System;
using ArgusLogs.DataAnnotation;
using ArgusLogs.Logging;

[AttributeUsage(AttributeTargets.Method | AttributeTargets.Class, AllowMultiple = false, Inherited = true)]
public class TrackPerformanceAttribute : OnMethodBoundaryAspect
{
    private readonly double _thresholdMs;

    public TrackPerformanceAttribute(double thresholdMs = 500)
    {
        _thresholdMs = thresholdMs;
    }

    public override void OnEntry(MethodExecutionArgs args)
    {
        // Automatically start the internal execution timer
        args.ForceStartTimer();
    }

    public override void OnSuccess(MethodExecutionArgs args)
    {
        args.ForceStopTimer();
        double elapsed = args.ElapsedMilliseconds ?? 0;

        if (elapsed > _thresholdMs)
        {
            ArgusLogs.Warning(
                $"Slow execution detected in {args.FormatMethodInfo()}",
                new {
                    DurationMs = elapsed,
                    ThresholdMs = _thresholdMs,
                    Method = args.MethodName,
                    Class = args.TypeName
                },
                category: "Performance"
            );
        }
    }

    public override void OnException(MethodExecutionArgs args)
    {
        args.ForceStopTimer();

        ArgusLogs.Error(
            $"Method execution failed during performance tracking in {args.FormatMethodInfo()}",
            args.Exception
        );
    }
}

Decorate your code

ReportGenerator.cs

public class ReportGenerator
{
    [TrackPerformance(thresholdMs: 250)] // Alert if generation takes > 250ms
    public void BuildDataSheet()
    {
        // Simulating heavy operations
        System.Threading.Thread.Sleep(300);
    }
}

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