使用 Prometheus 对 netcore api 进行自定义监控基于 prometheus-net.AspNetCore

• 准备Prometheus环境和Grafana （3.10）
• 手动或者cli 添加nuget包引用 prometheus-net.AspNetCore 
• 定义自定义middleview （需要其他的属性可以自己扩展这里随便举例两个属性）

  using Microsoft.AspNetCore.Builder;
  using Microsoft.AspNetCore.Http;
  using Microsoft.Extensions.Logging;
  using Prometheus;
  using System;
  using System.Collections.Generic;
  using System.Diagnostics;
  using System.Linq;
  using System.Threading.Tasks;
  
  namespace PrometheusTest2
  {
      public class RequestMiddleware
      {
          private readonly RequestDelegate _next;
          private readonly ILogger _logger;
  
          public RequestMiddleware(
              RequestDelegate next
              , ILoggerFactory loggerFactory
              )
          {
              this._next = next;
              this._logger = loggerFactory.CreateLogger<RequestMiddleware>();
          }
          // Name of the Response Header, Custom Headers starts with "X-"  
          //private const string RESPONSE_HEADER_RESPONSE_TIME = "X-Response-Time-ms";
          public async Task Invoke(HttpContext httpContext)
          {
              var path = httpContext.Request.Path.Value;
              var method = httpContext.Request.Method;
  　　         //定义接口请求次数 只增不减
              var counter = Metrics.CreateCounter("prometheus_demo_request_total", "HTTP Requests Total", new CounterConfiguration
              {
                  LabelNames = new[] { "path", "method", "status" }
              });
  
              //只统计成功的时间 （随着请求变化）
              var gauge = Metrics.CreateGauge("http_response_time", "Http Response Time ", new GaugeConfiguration
              {
                  LabelNames = new[] { "path", "method" }
              });
  
              var statusCode = 200;
              var watch = new Stopwatch();
              //var responseTime = "0";
              watch.Start();
              httpContext.Response.OnStarting(() =>
              {
                  // Stop the timer information and calculate the time   
                  watch.Stop();
                  //var responseTimeForCompleteRequest = watch.ElapsedMilliseconds;
                  // Add the Response time information in the Response headers.   
                  //responseTime = responseTimeForCompleteRequest.ToString();
                  if (path != "/metrics")
                  {
                      statusCode = httpContext.Response.StatusCode;
                      counter.Labels(path, method, statusCode.ToString()).Inc();
                      gauge.Labels(path, method).Inc();
                      gauge.Set(watch.ElapsedMilliseconds);
                  }
                  return Task.CompletedTask;
              });
              try
              {
                  await _next.Invoke(httpContext);
              }
              catch (Exception)
              {
                  statusCode = 500;
                  counter.Labels(path, method, statusCode.ToString()).Inc();
  
                  throw;
              }
  
          }
      }
  
      public static class RequestMiddlewareExtensions
      {
          public static IApplicationBuilder UseRequestMiddleware(this IApplicationBuilder builder)
          {
              return builder.UseMiddleware<RequestMiddleware>();
          }
      }
  }

• startup添加引用

     app.UseMetricServer();
  
     app.UseRequestMiddleware();

  
• 打开本地服务查看自定义监控属性
• 

•  配置Prometheus yml

   

  global:
    scrape_interval:     60s
    evaluation_interval: 60s
  
  scrape_configs:
    - job_name: prometheus
      static_configs:
        - targets: ['localhost:9090']
          labels:
            instance: prometheus
  
    - job_name: linux
      static_configs:
        - targets: ['192.168.3.10:9100']
          labels:
            instance: localhost
  
    - job_name: gotest
      static_configs:
        - targets: ['192.168.3.87:8080']
          labels:
            instance: windows test go
  
    - job_name: netcoretest
      scrape_interval: 15s
      scrape_timeout: 10s
      metrics_path: /metrics-text
      static_configs:
        - targets: ['192.168.3.87:5000']
          labels:
            instance: windows aspnet  test
  
    - job_name: netcoretest2
      static_configs:
        - targets: ['192.168.3.87:8081']
          labels:
            instance: windows test api

• 为了快速查看数据重启Prometheus服务  
• 使用语句快速查询自定义属性
• 在Grafana 配置仪表盘展示自定义属性
  • 首先配置数据源DataSource 参考https://www.cnblogs.com/chongyao/p/13993046.html
  • 添加dashboard 
  • 添加全局搜索条件 （这里监听的接口太多新增字段搜索）

    

    

    成功后如下图所示：

    

  • 添加 panel （我这里要算出接口的错误率  status=500/总请求数）

     点击Transform 算出结果集

  • 添加耗时面板 

  • 最终效果