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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