诊断客户端库

项目
05/10/2023

本文适用于：✔️ 针对目标应用的 .NET Core 3.0 SDK 和更高版本及要使用该库的 .NET Standard 2.0。

Microsoft.Diagnostics.NETCore.Client（也称为诊断客户端库）是一种托管库，该库支持你与 .NET Core 运行时 (CoreCLR) 交互，以实现各种与诊断相关的任务，如通过 EventPipe 进行跟踪、请求转储或附加 ICorProfiler。此库是许多诊断工具背后的支持库，例如 dotnet-counters、dotnet-trace、dotnet-gcdump、dotnet-dump 和 dotnet-monitor。使用此库，可以为自己编写针对特定方案自定义的诊断工具。

你可以通过将 PackageReference 添加到你的项目来获取 Microsoft.Diagnostics.NETCore.Client。该包托管在 NuGet.org 之上。

以下部分中的示例演示了如何使用 Microsoft.Diagnostics.NETCore.Client 库。其中一些示例还演示了如何使用 TraceEvent 库来分析事件负有效负载。

附加到进程并打印出所有 GC 事件

此代码片段演示了如何在信息级别使用带有 GC 关键字的 .NET 运行时提供程序启动 EventPipe 会话。它还演示了如何使用 TraceEvent 库提供的 EventPipeEventSource 类来分析传入的事件，并将其名称实时打印到控制台。

using Microsoft.Diagnostics.NETCore.Client;
using Microsoft.Diagnostics.Tracing;
using Microsoft.Diagnostics.Tracing.EventPipe;
using Microsoft.Diagnostics.Tracing.Parsers;
using System;
using System.Collections.Generic;
using System.Diagnostics.Tracing;

public class RuntimeGCEventsPrinter
{
    public static void PrintRuntimeGCEvents(int processId)
    {
        var providers = new List<EventPipeProvider>()
        {
            new EventPipeProvider("Microsoft-Windows-DotNETRuntime",
                EventLevel.Informational, (long)ClrTraceEventParser.Keywords.GC)
        };

        var client = new DiagnosticsClient(processId);
        using (EventPipeSession session = client.StartEventPipeSession(providers, false))
        {
            var source = new EventPipeEventSource(session.EventStream);

            source.Clr.All += (TraceEvent obj) => Console.WriteLine(obj.ToString());

            try
            {
                source.Process();
            }
            catch (Exception e)
            {
                Console.WriteLine("Error encountered while processing events");
                Console.WriteLine(e.ToString());
            }
        }
    }
}

编写核心转储

此示例演示了如何使用 DiagnosticsClient 触发核心转储的集合。

using Microsoft.Diagnostics.NETCore.Client;

public partial class Dumper
{
    public static void TriggerCoreDump(int processId)
    {
        var client = new DiagnosticsClient(processId);
        client.WriteDump(DumpType.Normal, "/tmp/minidump.dmp");
    }
}

当 CPU 使用率超过阈值时触发核心转储

此示例演示了如何监视 .NET 运行时发布的 cpu-usage 计数器，并在 CPU 使用率超出特定阈值时请求转储。

using Microsoft.Diagnostics.NETCore.Client;
using Microsoft.Diagnostics.Tracing;
using Microsoft.Diagnostics.Tracing.EventPipe;
using Microsoft.Diagnostics.Tracing.Parsers;
using System;
using System.Collections.Generic;
using System.Diagnostics.Tracing;

public partial class Dumper
{
    public static void TriggerDumpOnCpuUsage(int processId, int threshold)
    {
        var providers = new List<EventPipeProvider>()
        {
            new EventPipeProvider(
                "System.Runtime",
                EventLevel.Informational,
                (long)ClrTraceEventParser.Keywords.None,
                new Dictionary<string, string>
                {
                    ["EventCounterIntervalSec"] = "1"
                }
            )
        };
        var client = new DiagnosticsClient(processId);
        using (var session = client.StartEventPipeSession(providers))
        {
            var source = new EventPipeEventSource(session.EventStream);
            source.Dynamic.All += (TraceEvent obj) =>
            {
                if (obj.EventName.Equals("EventCounters"))
                {
                    var payloadVal = (IDictionary<string, object>)(obj.PayloadValue(0));
                    var payloadFields = (IDictionary<string, object>)(payloadVal["Payload"]);
                    if (payloadFields["Name"].ToString().Equals("cpu-usage"))
                    {
                        double cpuUsage = Double.Parse(payloadFields["Mean"].ToString());
                        if (cpuUsage > (double)threshold)
                        {
                            client.WriteDump(DumpType.Normal, "/tmp/minidump.dmp");
                        }
                    }
                }
            };
            try
            {
                source.Process();
            }
            catch (Exception) {}
        }
    }
}

在给定的秒数内触发 CPU 跟踪

此示例演示了如何使用默认 CLR 跟踪关键字以及示例探查器触发特定时间段的 EventPipe 会话。此后，它会读取输出流，并将这些字节写入文件。本质上讲，这就是 dotnet-trace 在内部用于编写跟踪文件的内容。

using Microsoft.Diagnostics.Tracing;
using Microsoft.Diagnostics.Tracing.Parsers;
using Microsoft.Diagnostics.NETCore.Client;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Diagnostics.Tracing;
using System.IO;
using System.Threading.Tasks;

public partial class Tracer
{
    public void TraceProcessForDuration(int processId, int duration, string traceName)
    {
        var cpuProviders = new List<EventPipeProvider>()
        {
            new EventPipeProvider("Microsoft-Windows-DotNETRuntime", EventLevel.Informational, (long)ClrTraceEventParser.Keywords.Default),
            new EventPipeProvider("Microsoft-DotNETCore-SampleProfiler", EventLevel.Informational, (long)ClrTraceEventParser.Keywords.None)
        };
        var client = new DiagnosticsClient(processId);
        using (var traceSession = client.StartEventPipeSession(cpuProviders))
        {
            Task copyTask = Task.Run(async () =>
            {
                using (FileStream fs = new FileStream(traceName, FileMode.Create, FileAccess.Write))
                {
                    await traceSession.EventStream.CopyToAsync(fs);
                }
            });

            Task.WhenAny(copyTask, Task.Delay(TimeSpan.FromMilliseconds(duration * 1000)));
            traceSession.Stop();
        }
    }
}

打印已发布诊断通道的进程名称

此示例演示了如何使用 DiagnosticsClient.GetPublishedProcesses API 来打印发布了诊断 IPC 通道的 .NET 进程名称。

using Microsoft.Diagnostics.NETCore.Client;
using System;
using System.Diagnostics;
using System.Linq;

public class ProcessTracker
{
    public static void PrintProcessStatus()
    {
        var processes = DiagnosticsClient.GetPublishedProcesses()
            .Select(Process.GetProcessById)
            .Where(process => process != null);

        foreach (var process in processes)
        {
            Console.WriteLine($"{process.ProcessName}");
        }
    }
}

实时分析事件

此示例演示了一个示例，在该示例中，我们创建了两个任务，一个任务用于通过 EventPipeEventSource 分析实时传入的事件，另一个任务用于读取用户输入的控制台输入信号，以使程序结束。如果在用户按 Enter 之前目标应用已退出，则应用将正常退出。否则，inputTask 会将 Stop 命令发送到管道并正常退出。

using Microsoft.Diagnostics.NETCore.Client;
using Microsoft.Diagnostics.Tracing;
using Microsoft.Diagnostics.Tracing.EventPipe;
using Microsoft.Diagnostics.Tracing.Parsers;
using System;
using System.Collections.Generic;
using System.Diagnostics.Tracing;
using System.Threading.Tasks;

public partial class Tracer
{
    public static void PrintEventsLive(int processId)
    {
        var providers = new List<EventPipeProvider>()
        {
            new EventPipeProvider("Microsoft-Windows-DotNETRuntime",
                EventLevel.Informational, (long)ClrTraceEventParser.Keywords.Default)
        };
        var client = new DiagnosticsClient(processId);
        using (var session = client.StartEventPipeSession(providers, false))
        {

            Task streamTask = Task.Run(() =>
            {
                var source = new EventPipeEventSource(session.EventStream);
                source.Clr.All += (TraceEvent obj) => Console.WriteLine(obj.EventName);
                try
                {
                    source.Process();
                }
                // NOTE: This exception does not currently exist. It is something that needs to be added to TraceEvent.
                catch (Exception e)
                {
                    Console.WriteLine("Error encountered while processing events");
                    Console.WriteLine(e.ToString());
                }
            });

            Task inputTask = Task.Run(() =>
            {
                Console.WriteLine("Press Enter to exit");
                while (Console.ReadKey().Key != ConsoleKey.Enter)
                {
                    Task.Delay(TimeSpan.FromMilliseconds(100));
                }
                session.Stop();
            });

            Task.WaitAny(streamTask, inputTask);
        }
    }
}

附加 ICorProfiler 探查器

此示例演示了如何通过探查器附加将 ICorProfiler 附加到进程。

using System;
using Microsoft.Diagnostics.NETCore.Client;

public class Profiler
{
    public static void AttachProfiler(int processId, Guid profilerGuid, string profilerPath)
    {
        var client = new DiagnosticsClient(processId);
        client.AttachProfiler(TimeSpan.FromSeconds(10), profilerGuid, profilerPath);
    }
}

通过