在自定义EventSource时，可以使用四种EventCounter：

• EventCounter：统计指标收集器，比如平均值，最大值，最小值

• PollingCounter：自定义统计指标收集器，通过自定义统计方法的方式实现对指标的统计

• IncrementingEventCounter：累加指标收集器，采集一定时间段内的指标汇总

• IncrementingPollingCounter：自定义累加指标收集器，通过自定义累函数，实现指标收集

本例先说一下用IncrementingEventCounter实现自定义EventSource。

本例是定义了一个WorkingEventSouce事件源，定义了WorkingEventListener监听器，和发送指标采集指标的类型IncrementingEventCounterDemo。

WorkingEventSouce事件源

[EventSource(Name = "WorkingEventSource")]
public sealed class WorkingEventSource : EventSource
{public static readonly WorkingEventSource Instance = new WorkingEventSource();private IncrementingEventCounter _requestCounter;/// <summary>/// working-time 是dotnet-counters  --counters的参数/// </summary>private WorkingEventSource() =>_requestCounter = new IncrementingEventCounter("working-time", this){DisplayName = "Request Processing Time",DisplayUnits = "ms"};/// <summary>/// Working发送业务指标/// </summary>/// <param name="elapsedMilliseconds"></param>public void Working(long elapsedMilliseconds){_requestCounter.Increment(elapsedMilliseconds);}protected override void Dispose(bool disposing){_requestCounter?.Dispose();_requestCounter = null;base.Dispose(disposing);}
}

WorkingEventListener监听器

/// <summary>
/// 指标输出委托
/// </summary>
/// <param name="key"></param>
/// <param name="value"></param>
public delegate void WriteContent(string key, string value);
/// <summary>
/// 指标监听器
/// </summary>
public class CustomEventListener : EventListener
{protected readonly string[] _countersName = new string[] { "WorkingEventSource" };public event WriteContent WriteEvent;protected override void OnEventSourceCreated(EventSource source){if (_countersName.Contains(source.Name)){EnableEvents(source, EventLevel.Verbose, EventKeywords.All, new Dictionary<string, string>(){["EventCounterIntervalSec"] = "1"});}}protected override void OnEventWritten(EventWrittenEventArgs eventData){if (!eventData.EventName.Equals("EventCounters")){return;}for (int i = 0; i < eventData.Payload.Count; ++i){if (eventData.Payload[i] is IDictionary<string, object> eventPayload){var counterName = "";var counterValue = "";if (eventPayload.TryGetValue("DisplayName", out object displayValue)){counterName = displayValue.ToString();}if (eventPayload.TryGetValue("Mean", out object value) ||eventPayload.TryGetValue("Increment", out value)){counterValue = value.ToString();}WriteEvent(counterName, counterValue);}}}
}

发送指标采集指标的类型IncrementingEventCounterDemo

 public class IncrementingEventCounterDemo{public static void Run(){var listener = new CustomEventListener();listener.WriteEvent += Listener_WriteEvent;new Thread(Working).Start();}/// <summary>///  以控制台方式展示采集到的指标/// </summary>/// <param name="key"></param>/// <param name="value"></param>private static void Listener_WriteEvent(string key, string value){Console.WriteLine($"{key}：{value}");}/// <summary>/// 模拟写业务指标，每秒写两次，i递增/// </summary>static void Working(){int i = 0;while (true){var count = i;Console.WriteLine(count);WorkingEventSource.Instance.Working(count);System.Threading.Thread.Sleep(500);i += 1;}}
}

结果，可以看到，每次都是时间段里数值之和

下图是跟踪EventListener的OnEventWritten的Payload有效载荷时的数据，可以看到有时间段内总和—Increment，次数，时间间隔等信息，这是因为当前计数据类型是IncrementingEventCounter。