引入Jaeger——封装

随着微服务的普及，微服务间的调用全链路跟踪也火了起来，Jaeger(https://www.jaegertracing.io/) 是CNCF孵化的全链路跟踪型项目，在.net core中，提供了一个Jaeger的Nuget(https://github.com/jaegertracing/jaeger-client-csharp) 包来使用。
本例封装就是用这个Nuget包来做成asp.net core中间件和action过滤器：中间件可以把所有经过管道的请求都跟踪起来，如果觉得这样的跟踪太重，或者没有必要收集所有请求，只跟踪有链路关联的请求，那就可以用action过滤器。

定义一个Options，这是自定义跟踪收集数据的配置属性

namespace JaegerSharp
{
/// <summary>
/// Jaeger选项
/// </summary>
public class JaegerOptions
{
/// <summary>
/// 是否启用Form数据转成Span
/// </summary>
public bool IsFormSpan { get; set; } = false;
/// <summary>
/// Form数据最大长度
/// </summary>
public int FormValueMaxLength { get; set; } = 100;
/// <summary>
/// 是否启用Query数据转成Span
/// </summary>
public bool IsQuerySpan { get; set; } = false;
/// <summary>
/// Query最大长度
/// </summary>
public int QueryValueMaxLength { get; set; } = 100;
/// <summary>
/// Form或Query中不作为Span的key集合
/// </summary>
public string[] NoSpanKeys { get; set; } = new string[] { "password", "pwd" };

}
}

跟踪中间件，把所有的请求都收集起来

using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using OpenTracing;
using OpenTracing.Propagation;
using System;
using System.IO;
using System.Linq;
using System.Threading.Tasks;

namespace JaegerSharp
{
/// <summary>
/// Jaeger中间件
/// </summary>
public class JaegerSharpMiddleware
{
/// <summary>
/// jaeger选项
/// </summary>
private readonly JaegerOptions _jaegerOptions;

private readonly ILogger<JaegerSharpMiddleware> _logger;
/// <summary>
/// 请求代理
/// </summary>
private readonly RequestDelegate _next;
public JaegerSharpMiddleware(RequestDelegate next, ILogger<JaegerSharpMiddleware> logger, JaegerOptions jaegerOptions = null)
{
_next = next;
_jaegerOptions = jaegerOptions;
_logger = logger;

}
/// <summary>
/// 调用管道
/// </summary>
/// <param name="context">上下文</param>
/// <param name="tracer">跟踪器</param>
/// <returns></returns>
public async Task InvokeAsync(HttpContext context, ITracer tracer)
{
_logger.LogInformation("jaeger调用");
var path = context.Request.Path;
if (Path.HasExtension(path))
{
await _next(context);
}
else
{
//接收传入的Headers
var callingHeaders = new TextMapExtractAdapter(context.Request.Headers.ToDictionary(m => m.Key, m => m.Value.ToString()));
var spanContex = tracer.Extract(BuiltinFormats.HttpHeaders, callingHeaders);
ISpanBuilder builder = null;
if (spanContex != null)
{
builder = tracer.BuildSpan("中间件Span").AsChildOf(spanContex);
}
else
{
builder = tracer.BuildSpan("中间件Span");
}
//开始设置Span
using (IScope scope = builder.StartActive(true))
{
scope.Span.SetOperationName(path);
// 记录请求信息到span
if (_jaegerOptions.IsQuerySpan)
{
foreach (var query in context.Request.Query)
{
//包含敏感词跳出
if (_jaegerOptions.NoSpanKeys.Contains(query.Key))
{
continue;
}
var value = query.Value.ToString().Length > _jaegerOptions.QueryValueMaxLength ? query.Value.ToString()?.Substring(0, _jaegerOptions.QueryValueMaxLength) : query.Value.ToString();
scope.Span.SetTag(query.Key, value);
}
}
if (_jaegerOptions.IsFormSpan && context.Request.HasFormContentType)
{
foreach (var form in context.Request.Form)
{
//包含敏感词跳出
if (_jaegerOptions.NoSpanKeys.Contains(form.Key))
{
continue;
}
var value = form.Value.ToString().Length > _jaegerOptions.FormValueMaxLength ? form.Value.ToString()?.Substring(0, _jaegerOptions.FormValueMaxLength) : form.Value.ToString();
scope.Span.SetTag(form.Key, value);
}
}
await _next(context);
}
}
}
}
}

扩展中间件

using Microsoft.AspNetCore.Builder;

namespace JaegerSharp
{
/// <summary>
/// 使用JaegerSharp中间件
/// </summary>
public static class JaegerSharpMiddlewareExtensions
{
public static IApplicationBuilder UseJaegerSharp(this IApplicationBuilder builder)
{
return builder.UseMiddleware<JaegerSharpMiddleware>(new JaegerOptions());
}
public static IApplicationBuilder UseJaegerSharp(this IApplicationBuilder builder, JaegerOptions jaegerOptions)
{
return builder.UseMiddleware<JaegerSharpMiddleware>(jaegerOptions);
}
}
}

action过滤器，用来准确收集跟踪信息

using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Filters;
using OpenTracing;
using OpenTracing.Propagation;
using System.Linq;

namespace JaegerSharp
{
/// <summary>
/// 使用Jaeger的Action过滤器添加Jaeger实列
/// </summary>
public class JaegerSharpAttribute : TypeFilterAttribute
{
public JaegerSharpAttribute() : base(typeof(JaegerFilterAttributeImpl))
{
}
/// <summary>
/// 真正实现Jaeger Scope的类
/// </summary>
private class JaegerFilterAttributeImpl : IActionFilter
{
private readonly ITracer _tracer;

public JaegerFilterAttributeImpl(ITracer tracer)
{
_tracer = tracer;
}
IScope _scope = null;
/// <summary>
/// 开始执行Action
/// </summary>
/// <param name="context"></param>
public void OnActionExecuting(ActionExecutingContext context)
{
var path = context.HttpContext.Request.Path;
var callingHeaders = new TextMapExtractAdapter(context.HttpContext.Request.Headers.ToDictionary(m => m.Key, m => m.Value.ToString()));
var spanContex = _tracer.Extract(BuiltinFormats.HttpHeaders, callingHeaders);
ISpanBuilder builder = null;
if (spanContex != null)
{
builder = _tracer.BuildSpan("中间件Span").AsChildOf(spanContex);
}
else
{
builder = _tracer.BuildSpan("中间件Span");
}
_scope = builder.StartActive(true);
_scope.Span.SetOperationName(path);
// 记录请求信息到span
foreach (var query in context.HttpContext.Request.Query)
{
_scope.Span.SetTag(query.Key, query.Value);
}
if (context.HttpContext.Request.HasFormContentType)
{

8000
foreach (var form in context.HttpContext.Request.Form)
{
_scope.Span.SetTag(form.Key, form.Value);
}
}
}
/// <summary>
/// Action结束执行
/// </summary>
/// <param name="context"></param>
public void OnActionExecuted(ActionExecutedContext context)
{
_scope?.Dispose();
}
}
}
}

封装Jaeger在asp.net core中的注放步骤，使注入简单

using Jaeger;
using Jaeger.Reporters;
using Jaeger.Samplers;
using Jaeger.Senders.Thrift;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using OpenTracing;
using OpenTracing.Util;
using System.Reflection;

namespace JaegerSharp
{
public static class JaegerSharpExtensions
{
/// <summary>
/// 注入Jaeger
/// </summary>
/// <param name="services">服务容器</param>
/// <param name="host">Jaeger agent host</param>
/// <param name="port">Jaeger agent port</param>
/// <param name="maxPacketSize">Jaeger agent maxpacketsize</param>
public static void AddJaegerSharp(this IServiceCollection services, string host, int port, int maxPacketSize)
{
services.AddSingleton<ITracer>(serviceProvider =>
{
var loggerFactory = serviceProvider.GetRequiredService<ILoggerFactory>();
var reporter = new RemoteReporter.Builder()
.WithLoggerFactory(loggerFactory)
.WithSender(new UdpSender(string.IsNullOrEmpty(host) ? UdpSender.DefaultAgentUdpHost : host,
port <= 100 ? UdpSender.DefaultAgentUdpCompactPort : port,
maxPacketSize <= 0 ? 0 : maxPacketSize))
.Build();
ITracer tracer = new Tracer.Builder(Assembly.GetEntryAssembly().GetName().Name)
.WithReporter(reporter)
.WithLoggerFactory(loggerFactory)
.WithSampler(new ConstSampler(true))
.Build();
GlobalTracer.Register(tracer);
return tracer;
});
}
}
}