Prometheus开发中间件Exporter过程详解

Prometheus 为开发这提供了客户端工具，用于为自己的中间件开发Exporter，对接Prometheus 。

目前支持的客户端

• Go

• Java

• Python

• Ruby

以go为例开发自己的Exporter

依赖包的引入

工程结构

[root@node1 data]# tree exporter/
exporter/
├── collector
│ └── node.go
├── go.mod
└── main.go

引入依赖包

require (
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 github.com/modern-go/reflect2 v1.0.1 // indirect
 github.com/prometheus/client_golang v1.1.0
   //借助gopsutil 采集主机指标
 github.com/shirou/gopsutil v0.0.0-20190731134726-d80c43f9c984
)

main.go

package main

import (
 "cloud.io/exporter/collector"
 "fmt"
 "github.com/prometheus/client_golang/prometheus"
 "github.com/prometheus/client_golang/prometheus/promhttp"
 "net/http"
)

func init() {
  //注册自身采集器
 prometheus.MustRegister(collector.NewNodeCollector())
}
func main() {
 http.Handle("/metrics", promhttp.Handler())
 if err := http.ListenAndServe(":8080", nil); err != nil {
   fmt.Printf("Error occur when start server ％v", err)
 }
}

为了能看清结果我将默认采集器注释,位置registry.go

func init() {
 //MustRegister(NewProcessCollector(ProcessCollectorOpts{}))
 //MustRegister(NewGoCollector())
}

/collector/node.go

代码中涵盖了Counter、Gauge、Histogram、Summary四种情况，一起混合使用的情况，具体的说明见一下代码中。

package collector

import (
 "github.com/prometheus/client_golang/prometheus"
 "github.com/shirou/gopsutil/host"
 "github.com/shirou/gopsutil/mem"
 "runtime"
 "sync"
)

var reqCount int32
var hostname string
type NodeCollector struct {
 requestDesc  *prometheus.Desc  //Counter
 nodeMetrics   nodeStatsMetrics //混合方式
 goroutinesDesc *prometheus.Desc  //Gauge
 threadsDesc  *prometheus.Desc //Gauge
 summaryDesc  *prometheus.Desc //summary
 histogramDesc *prometheus.Desc  //histogram
 mutex     sync.Mutex
}
//混合方式数据结构
type nodeStatsMetrics []struct {
 desc  *prometheus.Desc
 eval  func(*mem.VirtualMemoryStat) float64
 valType prometheus.ValueType
}

//初始化采集器
func NewNodeCollector() prometheus.Collector {
 host,_:= host.Info()
 hostname = host.Hostname
 return &NodeCollector{
   requestDesc: prometheus.NewDesc(
     "total_request_count",
     "请求数",
     []string{"DYNAMIC_HOST_NAME"}, //动态标签名称
     prometheus.Labels{"STATIC_LABEL1":"静态值可以放在这里","HOST_NAME":hostname}),
   nodeMetrics: nodeStatsMetrics{
     {
       desc: prometheus.NewDesc(
         "total_mem",
         "内存总量",
         nil, nil),
       valType: prometheus.GaugeValue,
       eval: func(ms *mem.VirtualMemoryStat) float64 { return float64(ms.Total) / 1e9 },
     },
     {
       desc: prometheus.NewDesc(
         "free_mem",
         "内存空闲",
         nil, nil),
       valType: prometheus.GaugeValue,
       eval: func(ms *mem.VirtualMemoryStat) float64 { return float64(ms.Free) / 1e9 },
     },

},
   goroutinesDesc:prometheus.NewDesc(
     "goroutines_num",
     "协程数.",
     nil, nil),
   threadsDesc: prometheus.NewDesc(
     "threads_num",
     "线程数",
     nil, nil),
   summaryDesc: prometheus.NewDesc(
     "summary_http_request_duration_seconds",
     "summary类型",
     []string{"code", "method"},
     prometheus.Labels{"owner": "example"},
   ),
   histogramDesc: prometheus.NewDesc(
     "histogram_http_request_duration_seconds",
     "histogram类型",
     []string{"code", "method"},
     prometheus.Labels{"owner": "example"},
   ),
 }
}

// Describe returns all descriptions of the collector.
//实现采集器Describe接口
func (n *NodeCollector) Describe(ch chan<- *prometheus.Desc) {
 ch <- n.requestDesc
 for _, metric := range n.nodeMetrics {
   ch <- metric.desc
 }
 ch <- n.goroutinesDesc
 ch <- n.threadsDesc
 ch <- n.summaryDesc
 ch <- n.histogramDesc
}
// Collect returns the current state of all metrics of the collector.
//实现采集器Collect接口,真正采集动作
func (n *NodeCollector) Collect(ch chan<- prometheus.Metric) {
 n.mutex.Lock()
 ch <- prometheus.MustNewConstMetric(n.requestDesc,prometheus.CounterValue,0,hostname)
 vm, _ := mem.VirtualMemory()
 for _, metric := range n.nodeMetrics {
   ch <- prometheus.MustNewConstMetric(metric.desc, metric.valType, metric.eval(vm))
 }

ch <- prometheus.MustNewConstMetric(n.goroutinesDesc, prometheus.GaugeValue, float64(runtime.NumGoroutine()))

num, _ := runtime.ThreadCreateProfile(nil)
 ch <- prometheus.MustNewConstMetric(n.threadsDesc, prometheus.GaugeValue, float64(num))

//模拟数据
 ch <- prometheus.MustNewConstSummary(
   n.summaryDesc,
   4711, 403.34,
   map[float64]float64{0.5: 42.3, 0.9: 323.3},
   "200", "get",
 )

//模拟数据
 ch <- prometheus.MustNewConstHistogram(
     n.histogramDesc,
     4711, 403.34,
     map[float64]uint64{25: 121, 50: 2403, 100: 3221, 200: 4233},
     "200", "get",
   )
 n.mutex.Unlock()
}

执行的结果http://127.0.0.1:8080/metrics

来源：https://www.cnblogs.com/-wenli/p/13424790.html