如何在Application Insights中扩展对传出http请求的依赖跟踪

Question

我有一个.NET core API，它执行到其他API的HTTP连接。我能够在Application Insights中的Dependency Event Types下可视化传出的HTTP请求，但它只有基本信息。我正在研究如何添加更多关于传出HTTP调用的信息（例如HTTP头）。

我研究了https://docs.microsoft.com/en-us/azure/azure-monitor/app/api-custom-events-metrics#trackdependency，但没有找到任何具体的方法。

Answer 1

我认为您正在寻找的是ITelemetryInitializer，它可以为依赖项遥测添加自定义属性。

对于.NET core web项目，您可以参考此链接。

我编写一个演示如下：

    public class MyTelemetryInitializer: ITelemetryInitializer
    {
        IHttpContextAccessor httpContextAccessor;

        public MyTelemetryInitializer(IHttpContextAccessor httpContextAccessor)
        {
            this.httpContextAccessor = httpContextAccessor;
        }

        public void Initialize(ITelemetry telemetry)
        {
            //only add custom property to dependency type, otherwise just return.
            var dependencyTelemetry = telemetry as DependencyTelemetry;
            if (dependencyTelemetry == null) return;

            if (!dependencyTelemetry.Context.Properties.ContainsKey("custom_dependency_headers_1"))
            {
                //the comment out code use to check the fields in Headers if you don't know
                //var s = httpContextAccessor.HttpContext.Request.Headers;
                //foreach (var s2 in s)
                //{
                //   var a1 = s2.Key;
                //    var a2 = s2.Value;
                //}

                dependencyTelemetry.Context.Properties["custom_dependency_headers_1"] = httpContextAccessor.HttpContext.Request.Headers["Connection"].ToString();
            }
        }

    }

public void ConfigureServices(IServiceCollection services)
{
//other code

//add this line of code here
services.AddSingleton<ITelemetryInitializer, MyTelemetryInitializer>();
}

3.测试结果，检查自定义属性是否添加到azure portal中->自定义属性：