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Histogram。
3、Summary:摘要
summary是采集展示百分位数,百分位定义:在一组由小到大的数字中,某个数字大于90%的数字,这个数字就是第90个的百分位数。
通过demo的来理解一下吧,假如我们业务需求是要知道订单金额10,30,50,70,90的百分位数,该怎么实现呢?
需要在MetricsHub.cs中添加Summary类型的指标收集集合:
using Prometheus; using System.Collections.Generic; namespace PrometheusSample.Middlewares { 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>>(); private static Dictionary<string, Summary> _summaryDictionary = new Dictionary<string, Summary>(); private static Dictionary<string, Histogram> _histogramDictionary = new Dictionary<string, Histogram>(); 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 Summary GetSummary(string key) { if (_summaryDictionary.ContainsKey(key)) { return _summaryDictionary[key]; } else { return null; } } public Histogram GetHistogram(string key) { if (_histogramDictionary.ContainsKey(key)) { return _histogramDictionary[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); } public void AddSummary(string key, Summary summary) { _summaryDictionary.Add(key, summary); } public void AddHistogram(string key, Histogram histogram) { _histogramDictionary.Add(key, histogram); } } }
接下来就要在BusinessMetricsMiddleware的中间件中添加处理Summary指标的代码了:
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(); } } var histogram = metricsHub.GetHistogram(context.Request.Path); if (histogram != null) { var parseResult = int.TryParse(result.Data.ToString(), out int i); if (parseResult) { histogram.Observe(i); } } var summary = metricsHub.GetSummary(context.Request.Path); if (summary != null) { var parseResult = int.TryParse(result.Data.ToString(), out int i); if (parseResult) { summary.Observe(i); } } } } } } finally { context.Response.Body = originalBody; } } } }
再就是在Starsup中配置对应url的Summary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} }); //histogram var orderHistogram = Metrics.CreateHistogram("business_order_histogram", "订单直方图。", new HistogramConfiguration { Buckets = Histogram.LinearBuckets(start: 1000, width: 1000, count: 6) }) ; metricsHub.AddHistogram("/order", orderHistogram); //summary var orderSummary = Metrics .CreateSummary("business_order_summary", "10分钟内的订单数量", new SummaryConfiguration { Objectives = new[] { new QuantileEpsilonPair(0.1, 0.05), new QuantileEpsilonPair(0.3, 0.05), new QuantileEpsilonPair(0.5, 0.05), new QuantileEpsilonPair(0.7, 0.05), new QuantileEpsilonPair(0.9, 0.05), } }); metricsHub.AddSummary("/order", orderSummary); services.AddSingleton(metricsHub); } } }
其实 new QuantileEpsilonPair(0.1, 0.05) 第一个参数是百分位,0.05是误差,范围是10%-5%,10%+5%。
最后一步,就是打开Grafana来配置展示图表了。
最终展示结果:
同时事例中给出了最大、最少、平均、汇总、当前值以供参考。
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