.NET6、Serilog及Application Insights升级后应用名称不显示问题

问题原因 #

升级到.NET6及最新版Serilog.Sinks.ApplicationInsights后，旧版本中自动将Serilog全局Properties里的Application映射到App Insights应用名称（即Cloud.RoleName）的默认行为已被移除，导致配置的应用名称无法正常显示。

解决方案 #

方法一：自定义Telemetry初始化器 #

通过实现ITelemetryInitializer，手动将Serilog上下文中的Application属性赋值给App Insights的RoleName：

1. 创建自定义初始化器类：

using Microsoft.ApplicationInsights.Channel;
using Microsoft.ApplicationInsights.Extensibility;
using Serilog.Context;

public class ApplicationNameTelemetryInitializer : ITelemetryInitializer
{
    public void Initialize(ITelemetry telemetry)
    {
        if (string.IsNullOrEmpty(telemetry.Context.Cloud.RoleName) && 
            LogContext.TryGetProperty("Application", out var appProperty))
        {
            // 去除字符串两端的引号（适配JSON配置的字符串属性格式）
            telemetry.Context.Cloud.RoleName = appProperty.Value.ToString().Trim('"');
        }
    }
}

2. 在Worker Service的DI容器中注册该初始化器：

// Program.cs中
builder.Services.AddSingleton<ITelemetryInitializer, ApplicationNameTelemetryInitializer>();

方法二：使用Serilog的Enrich直接添加属性 #

修改Serilog配置，将Application属性通过WithProperty enricher添加，确保属性能被日志上下文捕获：

"Enrich": [
  "FromLogContext",
  {
    "Name": "WithProperty",
    "Args": { "name": "Application", "value": "ApplicationName" }
  }
],
"WriteTo": [
  {
    "Name": "ApplicationInsights",
    "Args": {
      "restrictedToMinimumLevel": "Information",
      "telemetryConverter": "Serilog.Sinks.ApplicationInsights.TelemetryConverters.TraceTelemetryConverter, Serilog.Sinks.ApplicationInsights",
      "InstrumentationKey": "<Key>"
    }
  }
]

方法三：自定义Telemetry转换器 #

继承默认的TraceTelemetryConverter，在转换日志事件时手动设置应用名称：

1. 创建自定义转换器类：

using Serilog.Events;
using Serilog.Sinks.ApplicationInsights.TelemetryConverters;
using Microsoft.ApplicationInsights.DataContracts;
using System.Globalization;

public class CustomTraceTelemetryConverter : TraceTelemetryConverter
{
    protected override void Configure(TraceTelemetry telemetry, LogEvent logEvent, IFormatProvider formatProvider)
    {
        base.Configure(telemetry, logEvent, formatProvider);
        
        if (logEvent.Properties.TryGetValue("Application", out var appProperty))
        {
            telemetry.Context.Cloud.RoleName = appProperty.ToString().Trim('"');
        }
    }
}

2. 在Serilog配置中指定自定义转换器：

"WriteTo": [
  {
    "Name": "ApplicationInsights",
    "Args": {
      "restrictedToMinimumLevel": "Information",
      "telemetryConverter": "YourProjectNamespace.CustomTraceTelemetryConverter, YourProjectAssembly",
      "InstrumentationKey": "<Key>"
    }
  }
]

内容的提问来源于stack exchange，提问作者Fernando