.net 微服务jeager链路跟踪
在 .NET 微服务中集成 Jaeger 链路跟踪可以帮助你监控和分析服务之间的调用关系和性能瓶颈。下面是实现步骤和示例代码：
1. 安装必要的 NuGet 包
需要安装以下包到每个微服务项目中：
OpenTelemetry.Extensions.HostingOpenTelemetry.Instrumentation.AspNetCoreOpenTelemetry.Exporter.Jaeger
2. 配置 Jaeger 链路跟踪
在 Program.cs 中添加 Jaeger 配置：
using OpenTelemetry;
using OpenTelemetry.Resources;
using OpenTelemetry.Trace;var builder = WebApplication.CreateBuilder(args);// 添加服务
builder.Services.AddControllers();// 配置 Jaeger 链路跟踪
builder.Services.AddOpenTelemetryTracing(tracerProviderBuilder =>
{tracerProviderBuilder// 设置服务资源信息.SetResourceBuilder(ResourceBuilder.CreateDefault().AddService(serviceName: builder.Environment.ApplicationName, serviceVersion: "1.0.0"))// 启用 ASP.NET Core instrumentation.AddAspNetCoreInstrumentation()// 启用 HttpClient instrumentation (用于跟踪服务间调用).AddHttpClientInstrumentation()// 配置 Jaeger 导出器.AddJaegerExporter(options =>{// Jaeger 服务地址，默认端口是 6831options.AgentHost = "localhost";options.AgentPort = 6831;// 可选：配置服务名称（如果未通过 ResourceBuilder 设置）// options.ServiceName = builder.Environment.ApplicationName;});
});var app = builder.Build();// 中间件配置
app.UseRouting();
app.UseAuthorization();
app.MapControllers();app.Run();3. 手动创建自定义跨度（Span）
如果需要跟踪特定的代码块，可以手动创建跨度：
using Microsoft.AspNetCore.Mvc;
using OpenTelemetry.Trace;namespace JaegerDemo.Controllers;[ApiController]
[Route("[controller]")]
public class WeatherForecastController : ControllerBase
{private static readonly string[] Summaries = new[]{"Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"};private readonly ILogger<WeatherForecastController> _logger;private readonly Tracer _tracer;private readonly HttpClient _httpClient;public WeatherForecastController(ILogger<WeatherForecastController> logger, Tracer tracer,HttpClient httpClient){_logger = logger;_tracer = tracer;_httpClient = httpClient;}[HttpGet(Name = "GetWeatherForecast")]public async Task<IEnumerable<WeatherForecast>> Get(){// 创建自定义跨度using var customSpan = _tracer.StartActiveSpan("CustomWeatherProcessing");try{// 添加自定义标签customSpan.SetAttribute("location", "Beijing");// 调用其他服务（会自动被跟踪）var response = await _httpClient.GetAsync("https://api.example.com/weather");response.EnsureSuccessStatusCode();return Enumerable.Range(1, 5).Select(index => new WeatherForecast{Date = DateOnly.FromDateTime(DateTime.Now.AddDays(index)),TemperatureC = Random.Shared.Next(-20, 55),Summary = Summaries[Random.Shared.Next(Summaries.Length)]}).ToArray();}catch (Exception ex){// 记录错误到跨度customSpan.RecordException(ex);customSpan.SetStatus(Status.Error);throw;}}
}4. 启动 Jaeger 服务
可以使用 Docker 快速启动 Jaeger：
docker run -d --name jaeger \-e COLLECTOR_ZIPKIN_HOST_PORT=:9411 \-p 5775:5775/udp \-p 6831:6831/udp \-p 6832:6832/udp \-p 5778:5778 \-p 16686:16686 \-p 14268:14268 \-p 14250:14250 \-p 9411:9411 \jaegertracing/all-in-one:1.47
启动后，访问 http://localhost:16686 可以打开 Jaeger UI 查看跟踪数据。
5. 关键配置说明
ServiceName：每个微服务应该有唯一的服务名，便于在 Jaeger UI 中区分AgentHost和AgentPort：Jaeger Agent 的地址，默认是localhost:6831- 自动 instrumentation 会跟踪：
- HTTP 请求（ASP.NET Core）
- HttpClient 调用
- 数据库操作（需额外安装对应 instrumentation 包）
通过这种方式，你可以实现 .NET 微服务的分布式链路跟踪，帮助诊断跨服务调用中的问题。