asp.net core监控—引入Prometheus（三）

　　上一篇博文中说到Prometheus有四种指标类型：Counter（计数器）、Gauge（仪表盘）、Histogram（直方图）、Summary（摘要），并且我们做了一个Counter的Demo，接下来看看Gauge。

2、Gauge：仪表盘，有增有减

　　这个指标非常像汽车的车速表，指针是在一定范围内有增有减的。下面我们接着上一篇博文的Sample来说，现在需要实时监控处在下“单完成”，“支付完成”，“发货完成”的单据数据，和各三种状态的占比；我们知道一个订单在一个时刻只能是一种状态，我们可以在下单时增加计数order的指标，但当订单从order转到pay状态后，pay指标会增加，同时order指标会减少，这个场景就会用上了Gauge了。

　　有了这个思路，我们可以上手代码了，BusinessController的代码不变（因为我们实现了业务逻辑代码和监控数据指标采集分离），这里我们需要在MetricsHub.cs中添加Gauge类型的指标收集集合：

 public class MetricsHub

    {

        private static Dictionary<string, Counter> _counterDictionary = new Dictionary<string, Counter>();

        private static Dictionary<string, Dictionary<string, Gauge>> _gaugeDictionary = new Dictionary<string, Dictionary<string, Gauge>>();

        public Counter GetCounter(string key)

        {

            if (_counterDictionary.ContainsKey(key))

            {

                return _counterDictionary[key];

            }

            else

            {

                return null;

            }

        }

        public Dictionary<string, Gauge> GetGauge(string key)

        {

            if (_gaugeDictionary.ContainsKey(key))

            {

                return _gaugeDictionary[key];

            }

            else

            {

                return null;

            }

        }

        public void AddCounter(string key, Counter counter)

        {

            _counterDictionary.Add(key, counter);

        }

        public void AddGauge(string key, Dictionary<string, Gauge> gauges)

        {

            _gaugeDictionary.Add(key, gauges);

        }

    }

　　因为在上面分析中，我们一个动作，比如pay时，会触发两个指标的改变，order指标减少，pay指标增加，所以Gauge是一个Dictionary<string, Dictionary<string, Gauge>>类型，内部的字典存放减少和增加的Gauge的监控指标对象。

　　接下来就要在BusinessMetricsMiddleware的中间件中添加处理Gauge指标增加减少的代码了：

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();

                            }

                            var gauges = metricsHub.GetGauge(context.Request.Path);

                            if (gauges != null)

                            {

                                //存在增加指标+就Inc

                                if (gauges.ContainsKey("+"))

                                {

                                    gauges["+"].Inc();

                                }

                                //存在减少指标-就Dec

                                if (gauges.ContainsKey("-"))

                                {

                                    gauges["-"].Dec();

                                }

                            }

                        }

                    }

                }

            }

            finally

            {

                context.Response.Body = originalBody;

            }

        }

    }

}

　　再就是在Starsup中配置对应url的Gauge参数了：

using Microsoft.AspNetCore.Builder;

using Microsoft.AspNetCore.Hosting;

using Microsoft.Extensions.Configuration;

using Microsoft.Extensions.DependencyInjection;

using Microsoft.Extensions.Hosting;

using Microsoft.OpenApi.Models;

using Prometheus;

using PrometheusSample.Middlewares;

using PrometheusSample.Services;

using System.Collections.Generic;

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。"));

            //gauge

            var orderGauge = Metrics.CreateGauge("business_order_count", "当前下单数量。");

            var payGauge = Metrics.CreateGauge("business_pay_count", "当前支付数量。");

            var shipGauge = Metrics.CreateGauge("business_ship_count", "当前发货数据。");

            metricsHub.AddGauge("/order", new Dictionary<string, Gauge> {

                { "+", orderGauge}

            });

            metricsHub.AddGauge("/pay", new Dictionary<string, Gauge> {

                {"-",orderGauge},

                {"+",payGauge}

            });

            metricsHub.AddGauge("/ship", new Dictionary<string, Gauge> {

                {"+",shipGauge},

                {"-",payGauge}

            });

            services.AddSingleton(metricsHub);

        }

    }

}

　　最后一步，就是打开Grafana来配置展示图表了

　　订单状态数据仪表盘

　　订单状态比例图

　　最终的展示结果

　　上一篇中我们说过自定义业务计数器类型的步骤，其实仪盘的步骤也一样

　　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

　　想要更快更方便的了解相关知识，可以关注微信公众号

巴特西

asp.net core监控—引入Prometheus（三）

最新文章

热门文章