IncrementingPollingCounter.cs

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using System.Diagnostics.CodeAnalysis;
using System.Runtime.Versioning;
 
namespace System.Diagnostics.Tracing;
 
[UnsupportedOSPlatform("browser")]
public class IncrementingPollingCounter : DiagnosticCounter
{
    private double _increment;
 
    private double _prevIncrement;
 
    private readonly Func<double> _totalValueProvider;
 
    public TimeSpan DisplayRateTimeScale { get; set; }
 
    public IncrementingPollingCounter(string name, EventSource eventSource, Func<double> totalValueProvider)
        : base(name, eventSource)
    {
        if (totalValueProvider == null)
        {
            throw new ArgumentNullException("totalValueProvider");
        }
        _totalValueProvider = totalValueProvider;
        Publish();
    }
 
    public override string ToString()
    {
        return $"IncrementingPollingCounter '{base.Name}' Increment {_increment}";
    }
 
    internal void UpdateMetric()
    {
        try
        {
            lock (this)
            {
                _prevIncrement = _increment;
                _increment = _totalValueProvider();
            }
        }
        catch (Exception ex)
        {
            ReportOutOfBandMessage("ERROR: Exception during EventCounter " + base.Name + " getMetricFunction callback: " + ex.Message);
        }
    }
 
    [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode", Justification = "The DynamicDependency will preserve the properties of IncrementingCounterPayload")]
    [DynamicDependency(DynamicallyAccessedMemberTypes.PublicProperties, typeof(IncrementingCounterPayload))]
    internal override void WritePayload(float intervalSec, int pollingIntervalMillisec)
    {
        UpdateMetric();
        lock (this)
        {
            IncrementingCounterPayload incrementingCounterPayload = new IncrementingCounterPayload();
            incrementingCounterPayload.Name = base.Name;
            incrementingCounterPayload.DisplayName = base.DisplayName ?? "";
            incrementingCounterPayload.DisplayRateTimeScale = ((DisplayRateTimeScale == TimeSpan.Zero) ? "" : DisplayRateTimeScale.ToString("c"));
            incrementingCounterPayload.IntervalSec = intervalSec;
            incrementingCounterPayload.Series = $"Interval={pollingIntervalMillisec}";
            incrementingCounterPayload.CounterType = "Sum";
            incrementingCounterPayload.Metadata = GetMetadataString();
            incrementingCounterPayload.Increment = _increment - _prevIncrement;
            incrementingCounterPayload.DisplayUnits = base.DisplayUnits ?? "";
            base.EventSource.Write("EventCounters", new EventSourceOptions
            {
                Level = EventLevel.LogAlways
            }, new IncrementingPollingCounterPayloadType(incrementingCounterPayload));
        }
    }
}