asp.net core监控—引入Prometheus(二)

2020/10/26 14:11
阅读数 46

上一篇博文中,说明了怎么引进Prometheus到asp.net core项目中,因为是Demo,所以Prometheus和Grafana都是windows版本,本地执行的,生产环境上这些服务可以根据的公司的架构,放到适合的环境内,现在这些服务都支持跨平台化和容器化。并且在上篇博客中展示的是http请求的基础信息模板,本篇博客介绍自定义Prometheusr指标类型。

Prometheus有四种指标类型:Counter(计数器)、Gauge(仪表盘)、Histogram(直方图)、Summary(摘要),如果对业务的指标进行收集展示,在项目中是侵入式编程的,如果项目使用Prometheus.net进行对接Permetheus,是通过该包中的静态方法 Metrics.CreateCounter(),Metrics.CreateGauge(),Metrics.CreateSummary(),Metrics.CreateHistogram()来创建静态指标收集器,完成对业务指标收集的。

我们先来看具体Demo。

1、Counter:计数器,只增不减

先设置个业务场景:比如做一个商城,有用户注册(/register),下订单(/order),支付(/pay),发货(/ship)四个API,代码如下:

using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using PrometheusSample.Models;
using PrometheusSample.Services;
using System;
using System.Threading.Tasks;


namespace PrometheusSample.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class BusinessController : ControllerBase
    {
        private readonly ILogger<BusinessController> _logger;
        private readonly IOrderService _orderService;


        public BusinessController(ILogger<BusinessController> logger, IOrderService orderService)
        {
            _orderService = orderService;
            _logger = logger;
        }
        /// <summary>
        /// 注册
        /// </summary>
        /// <param name="username">用户名</param>
        /// <returns></returns>
        [HttpPost("/register")]
        public async Task<IActionResult> RegisterUser([FromBody] User user)
        {
            try
            {
                _logger.LogInformation("用户注册");
                var result = await _orderService.Register(user.UserName);
                if (result)
                {
                    return new JsonResult(new { Result = true });
                }
                else
                {
                    return new JsonResult(new { Result = false });
                }
            }
            catch (Exception exc)
            {
                _logger.LogCritical(exc, exc.Message);
                return new JsonResult(new { Result = false, Message = exc.Message });
            }
        }


        [HttpGet("/order")]
        public IActionResult Order(string orderno)
        {
            try
            {
                _logger.LogInformation("下单");             
                return new JsonResult(new { Result = true });
            }
            catch (Exception exc)
            {
                _logger.LogCritical(exc, exc.Message);
                return new JsonResult(new
                {
                    Result = false,
                    Message = exc.Message
                });
            }
        }
        [HttpGet("/pay")]
        public IActionResult Pay()
        {
            try
            {
                _logger.LogInformation("支付");
                return new JsonResult(new { Result = true });
            }
            catch (Exception exc)
            {
                _logger.LogCritical(exc, exc.Message);
                return new JsonResult(new { Result = false, Message = exc.Message });
            }
        }
        [HttpGet("/ship")]
        public IActionResult Ship()
        {
            try
            {
                _logger.LogInformation("发货");
                return new JsonResult(new { Result = true });
            }
            catch (Exception exc)
            {
                _logger.LogCritical(exc, exc.Message);
                return new JsonResult(new { Result = false, Message = exc.Message });
            }
        }
    }
}


上面是基本的业务Controller,为了降低依赖,我们的业务指标收集统一到一个中间件中去收集,中间件根据请求的url,和返回的数据结果数据进行业务指标数据的收集,当然也可以引入action过滤器或MediatR等中介者模式的组件来隔离业务逻辑的开发与监控数据的采集。

本例是用中间件的方式,首先定义一个静态的指标收集器:

   public class MetricsHub
    {
        private static Dictionary<string, Counter> _counterDictionary = new Dictionary<string, Counter>();
         public Counter GetCounter(string key)
        {
            if (_counterDictionary.ContainsKey(key))
            {
                return _counterDictionary[key];
            }
            else
            {
                return null;
            }
        }
        public void AddCounter(string key, Counter counter)
        {
            _counterDictionary.Add(key, counter);
        }
    }

定义中间件BusinessMetricsMiddleware

using Microsoft.AspNetCore.Http;
using PrometheusSample.Models;
using System.IO;
using System.Threading.Tasks;


namespace PrometheusSample.Middlewares
{
    /// <summary>
    /// 请求记录中间件
    /// </summary>
    public class BusinessMetricsMiddleware
    {
        private readonly RequestDelegate _next;
        public BusinessMetricsMiddleware(RequestDelegate next)
        {
            _next = next;
        }


        public async Task InvokeAsync(HttpContext context, MetricsHub metricsHub)
        {
            var originalBody = context.Response.Body;
            try
            {
                using (var memStream = new MemoryStream())
                {
                    //从管理返回的Response中取出返回数据,根据返回值进行监控指标计数
                    context.Response.Body = memStream;
                    await _next(context);


                    memStream.Position = 0;
                    string responseBody = new StreamReader(memStream).ReadToEnd();
                    memStream.Position = 0;
                    await memStream.CopyToAsync(originalBody);
                    if (metricsHub.GetCounter(context.Request.Path) != null || metricsHub.GetGauge(context.Request.Path) != null)
                    {
                        //这里约定所有action返回值是一个APIResult类型
                        var result = System.Text.Json.JsonSerializer.Deserialize<APIResult>(responseBody, new System.Text.Json.JsonSerializerOptions { PropertyNameCaseInsensitive = true });
                        if (result != null && result.Result)
                        {
                            //获取到Counter
                            var counter = metricsHub.GetCounter(context.Request.Path);
                            if (counter != null)
                            {
                                //计数
                                counter.Inc();
                            }
                        }
                    }
                }
            }
            finally
            {
                context.Response.Body = originalBody;
            }
        }
    }
}

中间件中,只要action请求返回的Result为true,就会计数,这样做的前提条件是业务返回值有统一约定;但每个action返回不可能都一样的,如果有特例,可以用action过滤器或中介者模式组件来对应。

再看一下Starup中是怎么配置这个中间件的:

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Microsoft.OpenApi.Models;
using Prometheus;
using PrometheusSample.Middlewares;
using PrometheusSample.Services;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;


namespace PrometheusSample
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }


        public IConfiguration Configuration { get; }


        public void ConfigureServices(IServiceCollection services)
        {
            MetricsHandle(services);
            services.AddScoped<IOrderService, OrderService>();
            services.AddControllers();
            services.AddSwaggerGen(c =>
            {
                c.SwaggerDoc("v1", new OpenApiInfo { Title = "PrometheusSample", Version = "v1" });
            });
        }


        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseSwagger();
                app.UseSwaggerUI(c => c.SwaggerEndpoint("/swagger/v1/swagger.json", "PrometheusSample v1"));
            }


            app.UseRouting();
            //http请求的中间件
            app.UseHttpMetrics();
            app.UseAuthorization();


            //自定义业务跟踪
            app.UseBusinessMetrics();


            app.UseEndpoints(endpoints =>
            {
                //映射监控地址为  /metrics
                endpoints.MapMetrics();
                endpoints.MapControllers();
            });
        }
        /// <summary>
        /// 处理监控事项
        /// </summary>
        /// <param name="services"></param>
        void MetricsHandle(IServiceCollection services)
        {
            var metricsHub = new MetricsHub();
            //counter
            metricsHub.AddCounter("/register", Metrics.CreateCounter("business_register_user", "注册用户数。"));
            metricsHub.AddCounter("/order", Metrics.CreateCounter("business_order_total", "下单总数。"));
            metricsHub.AddCounter("/pay", Metrics.CreateCounter("business_pay_total", "支付总数。"));
            metricsHub.AddCounter("/ship", Metrics.CreateCounter("business_ship_total", "发货总数。"));
            services.AddSingleton(metricsHub);
        }
    }
}

MetricsHandle中,我们添加了四个action,分别对应的四个计数器,这样,当这四个url有请求,并且返回值中的result=true时,就会往对应的计数器上计数。

这样数据收集好了,现在开始在Grafana中配置显示的图表了:

订单各状态总数配置:

订单各状态30秒内数量跟踪折线

最后的运行结果是:

总结实现自定义业务计数器步骤:

1、分析业务,规划好监控跟踪指标

2、定义指标收集器

3、侵入编程(尽量在开发时分离业务实现与监控指票的收集代码)收集指标

4、开发grafana展示模板,完成展示

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