netcore/System.Private.CoreLib/shared/System/Diagnostics/Tracing/IncrementingPollingCounter.cs

   1 // Licensed to the .NET Foundation under one or more agreements.
   2 // The .NET Foundation licenses this file to you under the MIT license.
   3 // See the LICENSE file in the project root for more information.
   4
   5 #if ES_BUILD_STANDALONE
   6 using System;
   7 #endif
   8
   9 #if ES_BUILD_STANDALONE
  10 namespace Microsoft.Diagnostics.Tracing
  11 #else
  12 namespace System.Diagnostics.Tracing
  13 #endif
  14 {
  15     /// <summary>
  16     /// IncrementingPollingCounter is a variant of EventCounter for variables that are ever-increasing.
  17     /// Ex) # of exceptions in the runtime.
  18     /// It does not calculate statistics like mean, standard deviation, etc. because it only accumulates
  19     /// the counter value.
  20     /// Unlike IncrementingEventCounter, this takes in a polling callback that it can call to update
  21     /// its own metric periodically.
  22     /// </summary>
  23     public partial class IncrementingPollingCounter : DiagnosticCounter
  24     {
  25         /// <summary>
  26         /// Initializes a new instance of the <see cref="IncrementingPollingCounter"/> class.
  27         /// IncrementingPollingCounter live as long as the EventSource that they are attached to unless they are
  28         /// explicitly Disposed.
  29         /// </summary>
  30         /// <param name="name">The name.</param>
  31         /// <param name="eventSource">The event source.</param>
  32         public IncrementingPollingCounter(string name, EventSource eventSource, Func<double> totalValueProvider) : base(name, eventSource)
  33         {
  34             if (totalValueProvider == null)
  35                 throw new ArgumentNullException(nameof(totalValueProvider));
  36
  37             _totalValueProvider = totalValueProvider;
  38             Publish();
  39         }
  40
  41         public override string ToString() => $"IncrementingPollingCounter '{Name}' Increment {_increment}";
  42
  43         public TimeSpan DisplayRateTimeScale { get; set; }
  44         private double _increment;
  45         private double _prevIncrement;
  46         private readonly Func<double> _totalValueProvider;
  47
  48         /// <summary>
  49         /// Calls "_totalValueProvider" to enqueue the counter value to the queue.
  50         /// </summary>
  51         internal void UpdateMetric()
  52         {
  53             try
  54             {
  55                 lock (this)
  56                 {
  57                     _prevIncrement = _increment;
  58                     _increment = _totalValueProvider();
  59                 }
  60             }
  61             catch (Exception ex)
  62             {
  63                 ReportOutOfBandMessage($"ERROR: Exception during EventCounter {Name} getMetricFunction callback: " + ex.Message);
  64             }
  65         }
  66
  67         internal override void WritePayload(float intervalSec, int pollingIntervalMillisec)
  68         {
  69             UpdateMetric();
  70             lock (this)     // Lock the counter
  71             {
  72                 IncrementingCounterPayload payload = new IncrementingCounterPayload();
  73                 payload.Name = Name;
  74                 payload.DisplayName = DisplayName ?? "";
  75                 payload.DisplayRateTimeScale = (DisplayRateTimeScale == TimeSpan.Zero) ? "" : DisplayRateTimeScale.ToString("c");
  76                 payload.IntervalSec = intervalSec;
  77                 payload.Series = $"Interval={pollingIntervalMillisec}"; // TODO: This may need to change when we support multi-session
  78                 payload.CounterType = "Sum";
  79                 payload.Metadata = GetMetadataString();
  80                 payload.Increment = _increment - _prevIncrement;
  81                 payload.DisplayUnits = DisplayUnits ?? "";
  82                 EventSource.Write("EventCounters", new EventSourceOptions() { Level = EventLevel.LogAlways }, new IncrementingPollingCounterPayloadType(payload));
  83             }
  84         }
  85     }
  86
  87     /// <summary>
  88     /// This is the payload that is sent in the with EventSource.Write
  89     /// </summary>
  90     [EventData]
  91     internal class IncrementingPollingCounterPayloadType
  92     {
  93         public IncrementingPollingCounterPayloadType(IncrementingCounterPayload payload) { Payload = payload; }
  94         public IncrementingCounterPayload Payload { get; set; }
  95     }
  96 }