以下是一个示例代码,演示如何从OpenTelemetry中提取Feed服务器定时标头:
using System;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using OpenTelemetry.Context.Propagation;
namespace OpenTelemetryExample
{
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddControllers();
}
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
// 创建OpenTelemetry的HttpTraceContext传播实例
var traceContext = new HttpTraceContextPropagator();
// 配置OpenTelemetry提取器中间件
app.Use(async (context, next) =>
{
// 从请求头中提取TraceContext
var headers = context.Request.Headers;
var traceContextHeader = headers["traceparent"].ToString();
var traceStateHeader = headers["tracestate"].ToString();
// 创建当前活动的TraceContext
var activityContext = traceContext.Extract(default, headers, (header, name, carrier) =>
{
carrier.Add(name, header);
});
// 开始一个新的Activity
using (var activity = new Activity("Processing Request"))
{
// 设置当前活动的TraceContext
activity.SetParentId(activityContext.ActivityTraceId, activityContext.ActivitySpanId);
// 设置TraceState
activity.TraceStateString = traceStateHeader;
// 执行下一个中间件
await next.Invoke();
}
});
app.UseRouting();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
endpoints.MapGet("/", async context =>
{
// 获取当前的Activity
var currentActivity = Activity.Current;
// 从Activity中提取TraceContext信息
var traceId = currentActivity.TraceId;
var spanId = currentActivity.SpanId;
var traceState = currentActivity.TraceStateString;
// 返回提取的TraceContext信息
await context.Response.WriteAsync($"TraceId: {traceId}\nSpanId: {spanId}\nTraceState: {traceState}");
});
});
}
}
public class Program
{
public static void Main(string[] args)
{
CreateHostBuilder(args).Build().Run();
}
public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.ConfigureWebHostDefaults(webBuilder =>
{
webBuilder.UseStartup();
});
}
}
在这个示例中,我们创建了一个ASP.NET Core项目,并使用OpenTelemetry的HttpTraceContextPropagator
类来提取请求头中的TraceContext信息。在Configure
方法中,我们使用了一个中间件来提取请求头中的TraceContext,并将其设置为当前活动的TraceContext。然后,我们在MapGet
处理程序中获取当前活动的TraceContext信息,并将其返回给客户端。
要使用此示例,您需要确保已经安装了以下NuGet包:
OpenTelemetry
OpenTelemetry.Context.Propagation
Microsoft.AspNetCore.Mvc
您可以使用Visual Studio或者通过命令行运行dotnet run
来启动应用程序。