Azure隔离式工作进程自定义遥测无法写入Application Insights问题

1. 补充必要的NuGet包 #

在你的csproj中添加隔离进程专用的App Insights集成包：

<PackageReference Include="Microsoft.Azure.Functions.Worker.ApplicationInsights" Version="1.0.0" />

该版本与你当前使用的Microsoft.Azure.Functions.Worker 1.10.0版本兼容。

2. 修改Program.cs配置 #

必须先初始化Worker默认配置，再注册App Insights服务和自定义遥测初始化器，确保服务加载顺序正确：

var host = new HostBuilder()
    .ConfigureFunctionsWorkerDefaults() // 初始化隔离进程基础服务（日志、绑定等）
    .ConfigureServices((_, services) =>
    {
        services
            .AddHttpClient()
            .AddApplicationInsightsTelemetryWorkerService() // 注册App Insights Worker服务
            .AddSingleton<ITelemetryInitializer, CustomTelemetry>(); // 添加自定义遥测初始化器
    })
    .Build();

host.Run();

3. 修复CustomTelemetry中的重复键问题 #

避免因重复添加相同键的属性导致运行时异常，添加前先检查键是否存在：

public class CustomTelemetry : ITelemetryInitializer
{
    public void Initialize(ITelemetry telemetry)
    {
        // 全局属性：先检查再添加
        if (!telemetry.Context.GlobalProperties.ContainsKey("GlobalProperties"))
        {
            telemetry.Context.GlobalProperties.Add("GlobalProperties", "FromCustomTelemetryYeeeeeeyyy");
        }

        if (telemetry is TraceTelemetry traceTelemetry)
        {
            if (!traceTelemetry.Context.GlobalProperties.ContainsKey("GlobalProperties"))
            {
                traceTelemetry.Context.GlobalProperties.Add("GlobalProperties", "FromCustomTelemetryYeeeeeeyyy");
            }
            if (!traceTelemetry.Properties.ContainsKey("CustomTraceTelemetry"))
            {
                traceTelemetry.Properties.Add("CustomTraceTelemetry", "FromCustomTelemetryYeeeeeeyyy");
            }
        }

        if (telemetry is ISupportProperties itemProperties)
        {
            if (!itemProperties.Properties.ContainsKey("customProp"))
            {
                itemProperties.Properties["customProp"] = "customValue";
            }
        }

        if (telemetry is RequestTelemetry requestTelemetry)
        {
            if (!requestTelemetry.Context.GlobalProperties.ContainsKey("GlobalProperties"))
            {
                requestTelemetry.Context.GlobalProperties.Add("GlobalProperties", "FromCustomTelemetryYeeeeeeyyy");
            }
            if (!requestTelemetry.Properties.ContainsKey("LoggedInUserName"))
            {
                requestTelemetry.Properties.Add("LoggedInUserName", "DummyUser");
            }
        }
    }
}

4. 配置host.json确保日志流向App Insights #

在项目根目录的host.json中添加日志规则，确保App Insights能捕获到函数日志：

{
  "version": "2.0",
  "logging": {
    "applicationInsights": {
      "samplingSettings": {
        "isEnabled": true,
        "excludedTypes": "Request"
      },
      "enableLiveMetricsFilters": true
    },
    "logLevel": {
      "default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  }
}

5. 验证配置 #

部署或本地运行函数后，触发Http函数，在Application Insights的日志中执行以下Kusto查询验证自定义属性：

traces
| where customDimensions contains "customProp"
| project timestamp, message, customDimensions

查询结果应包含你定义的所有自定义属性。

本地运行时，需确保local.settings.json中配置了APPINSIGHTS_INSTRUMENTATIONKEY或APPLICATIONINSIGHTS_CONNECTION_STRING。

内容的提问来源于stack exchange，提问作者Serhat