Jaeger是收集全链路跟踪的信息，在Jaeger收集的信息中，有请求的url信息，有每个请求的时间间隔，借助这些信息可以进行报警，比如一次较长的请求，或者是某些请求的次数和先后等。不管报警的业务规则是什么，首先得收集Jaeger中的信息。

　　Jaeger有api可以提供这些信息，比如

　　/api/services，获取所有服务

　　/api/traces?service={servicename}获取该服务下的所有跟踪

　　/api/traces/{traceid}获取某个跟踪的信息等

　　/api/traces?end={endtime}&limit={20}&lookback={1h}&service={servicename}&start={starttime}按条件查询跟踪信息等api

下面代码定义Jaeger中的实体类，类中的属性可以根据自己的型业务规则收集，这里定义不完整

 

using System.Collections.Generic;

namespace JaegerAlert
{
    /// <summary>
    /// 服务报警
    /// </summary>
    public class AlertList
    {
        public string ServiceName { get; set; }
        public List<AlertItem> Alerts { get; set; }
    }
    /// <summary>
    /// 报警条目
    /// </summary>
    public class AlertItem
    {
        public string TraceID { get; set; }
        public long StartTime { get; set; }

        public long Duration { get; set; }

        public string Method { get; set; }

        public string Operation { get; set; }
    }

    /// <summary>
    /// 服务数据
    /// </summary>
    public class ServicesData
    {
        public string[] Data { get; set; }
        public int Total { get; set; }
        public int Limit { get; set; }
        public int Offset { get; set; }
    }

    /// <summary>
    /// 跟踪数据
    /// </summary>
    public class TracesData
    {
        public TracesItem[] Data { get; set; }
        public int Total { get; set; }
        public int Limit { get; set; }
        public int Offset { get; set; }
    }
    /// <summary>
    /// 跟踪条目
    /// </summary>
    public class TracesItem
    {
        public string TraceID { get; set; }

        public Span[] Spans { get; set; }
    }
    /// <summary>
    /// Span
    /// </summary>
    public class Span
    {
        public string TraceID { get; set; }
        public string SpanID { get; set; }
        public bool IsAlertMark => TraceID == SpanID;
        public int Flags { get; set; }
        public string OperationName { get; set; }
        public long StartTime { get; set; }

        public long Duration { get; set; }
        public Tag[] Tags { get; set; }
    }
    /// <summary>
    /// Tag
    /// </summary>
    public class Tag
    {
        public string Key { get; set; }
        public string Type { get; set; }

        public string Value { get; set; }
    }
}

这里简单进行了收集，转换成了自己的数据集合，方便对接自己的报警平台：

using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Threading.Tasks;

namespace JaegerAlert.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class HomeController : ControllerBase
    {
        private readonly IHttpClientFactory _clientFactory;
        private readonly ILogger<HomeController> _logger;

        public HomeController(ILogger<HomeController> logger, IHttpClientFactory clientFactory)
        {
            _clientFactory = clientFactory;
            _logger = logger;
        }

        [HttpGet]
        public async Task<IEnumerable<AlertList>> Get()
        {
            _logger.LogInformation("获取警报列表");
            return await GetServices();
        }
        /// <summary>
        /// 获取所有服务
        /// </summary>
        /// <returns></returns>
        async Task<IEnumerable<AlertList>> GetServices()
        {
            var service = await GetJaegerServices();
            var services = new List<AlertList>();
            foreach (var serviceName in service.Data)
            {
                if (serviceName == "jaeger-query")
                {
                    continue;
                }
                var alerts = new List<AlertItem>();
                var tracesModels = await GetJaegerTraces(serviceName);
                foreach (var traces in tracesModels.Data)
                {
                    foreach (var span in traces.Spans)
                    {
                        if (span.IsAlertMark)
                        {
                            var method = span.Tags.SingleOrDefault(s => s.Key == "http.method")?.Value;
                            var operation = span.Tags.SingleOrDefault(s => s.Key == "http.url")?.Value;
                            alerts.Add(new AlertItem { TraceID = traces.TraceID, Duration = span.Duration, Method = method, Operation = operation, StartTime = span.StartTime });
                        }
                    }
                }
                services.Add(new AlertList() { ServiceName = serviceName, Alerts = alerts });
            }
            return services;
        }

        /// <summary>
        /// 获取服务下的跟踪条目
        /// </summary>
        /// <param name="serviceName"></param>
        /// <returns></returns>
        async Task<TracesData> GetJaegerTraces(string serviceName)
        {
            using var client = _clientFactory.CreateClient("Jaeger");
            var request = new HttpRequestMessage(HttpMethod.Get, $"/api/traces?service={serviceName}");

            using var response = await client.SendAsync(request);
            if (response.IsSuccessStatusCode)
            {
                var jsonString = await response.Content.ReadAsStringAsync();
                var traces = Newtonsoft.Json.JsonConvert.DeserializeObject<TracesData>(jsonString);
                return traces;
            }
            else
            {
                return new TracesData();
            }
        }
        /// <summary>
        /// 获取服务
        /// </summary>
        /// <returns></returns>
        async Task<ServicesData> GetJaegerServices()
        {
            using var client = _clientFactory.CreateClient("Jaeger");
            var request = new HttpRequestMessage(HttpMethod.Get, "/api/services");
            using var response = await client.SendAsync(request);
            if (response.IsSuccessStatusCode)
            {
                var jsonString = await response.Content.ReadAsStringAsync();
                var service = Newtonsoft.Json.JsonConvert.DeserializeObject<ServicesData>(jsonString);
                return service;
            }
            else
            {
                return new ServicesData();
            }
        }
    }   
}

请求结果：

 

　　收集到数据后，就可以应用到报警平台上，如果报警平台有api，可以进行调用处理；还可以把这些数据推送到时序数据库中，如InfluxDB，再通过Grafana展示出来，进行实时展时跟踪，关于跟踪的细节和业务规则有关系，如果以后工作中遇到这类处理，到时再追加一篇博文进行细说。

 

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