.NET 8独立函数应用集成Application Insights遇键控服务异常求解决

问题场景 #

我有一个.NET 8 Isolated Functions应用，已为其添加Application Insights，宿主构建器代码如下：

var host = new HostBuilder()
    .ConfigureFunctionsWebApplication()
    .ConfigureServices((context, services) =>
    {
        services.AddApplicationInsightsTelemetryWorkerService();
        services.ConfigureFunctionsApplicationInsights();
    })
    .Build();

执行services.AddApplicationInsightsTelemetryWorkerService();时抛出如下异常：

System.InvalidOperationException
  HResult=0x80131509
  Message=This service descriptor is keyed. Your service provider may not support keyed services.
  Source=Microsoft.Extensions.DependencyInjection.Abstractions
  StackTrace:
   at Microsoft.Extensions.DependencyInjection.ServiceDescriptor.ThrowKeyedDescriptor() in Microsoft.Extensions.DependencyInjection\ServiceDescriptor.cs:line 483

解决方案 #

1. 移除冗余的服务注册调用 #

.NET 8 Isolated Functions的ConfigureFunctionsWebApplication()已经自动集成了Application Insights的基础服务配置，无需手动调用AddApplicationInsightsTelemetryWorkerService。仅保留ConfigureFunctionsApplicationInsights()即可，它会负责配置Functions专属的Application Insights参数。

修改后的代码：

var host = new HostBuilder()
    .ConfigureFunctionsWebApplication()
    .ConfigureServices((context, services) =>
    {
        services.ConfigureFunctionsApplicationInsights();
    })
    .Build();

2. 确保NuGet包版本一致 #

检查所有与Azure Functions Worker相关的NuGet包（例如Microsoft.Azure.Functions.Worker、Microsoft.Azure.Functions.Worker.ApplicationInsights等）版本是否与.NET 8兼容，且保持版本统一，避免因依赖版本不匹配引发的服务注册冲突。

3. 自定义Application Insights配置（可选） #

如果需要对遥测行为进行自定义配置，可以通过Configure<ApplicationInsightsServiceOptions>来设置，示例如下：

var host = new HostBuilder()
    .ConfigureFunctionsWebApplication()
    .ConfigureServices((context, services) =>
    {
        services.ConfigureFunctionsApplicationInsights();
        services.Configure<ApplicationInsightsServiceOptions>(options =>
        {
            // 示例：设置采样率
            options.SamplingSettings = new SamplingSettings
            {
                IsEnabled = true,
                MaxTelemetryItemsPerSecond = 5
            };
            // 其他自定义配置，如禁用特定遥测类型等
        });
    })
    .Build();

内容的提问来源于stack exchange，提问作者Peter Morris