使用golang 自定义编写开发 Prometheus exporter

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锅包肉
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    Exporter是基于Prometheus实施的监控系统中重要的组成部分，承担数据指标的采集工作，官方的exporter列表中已经包含了常见的绝大多数的系统指标监控，比如用于机器性能监控的node_exporter, 用于网络设备监控的snmp_exporter等等。这些已有的exporter对于监控来说，仅仅需要很少的配置工作就能提供完善的数据指标采集。
    prometheus四种类型的指标Counter 计数，Gauge 观测类，Histogram 直方，Summary 摘要 用golang语言如何构造这4种类型对应的指标，二是搞清楚修改指标值的场景和方式。

    不带label的基本例子

    
package main

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
    "net/http"
)

func main() {
    // 定义指标
    cpuUsage := prometheus.NewGauge(prometheus.GaugeOpts{
        Name:        "cpu_usage",                              // 指标名称
        Help:        "this is test metrics cpu usage",         // 帮助信息

    })
    // 给指标设置值
    cpuUsage.Set(29.56)
    // 注册指标
    prometheus.MustRegister(cpuUsage)
    // 暴露指标
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe("localhost:9100", nil)
}

    image.png

    带有固定label指标的例子

    image.png

    image.png

    带有非固定label指标的例子

    package main

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
    "net/http"
)

func main() {
    //定义带有不固定label的指标
    mtu := prometheus.NewGaugeVec(prometheus.GaugeOpts{
        Name: "interface_mtu",
        Help: "网卡接口MTU",
    }, []string{"interface", "Machinetype"})

    // 给指标设置值
    mtu.WithLabelValues("lo", "host").Set(1500)
    mtu.WithLabelValues("ens32", "host").Set(1500)
    mtu.WithLabelValues("eth0", "host").Set(1500)

    // 注册指标
    prometheus.MustRegister(mtu)

    // 暴露指标
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe("localhost:9100", nil)
}

    image.png

    2. Counter指标类型

    不带label的基本例子

    package main

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
    "net/http"
)

func main() {
    // 定义指标
    reqTotal := prometheus.NewCounter(prometheus.CounterOpts{
        Name: "current_request_total",
        Help: "当前请求总数",
    })
    // 注册指标
    prometheus.MustRegister(reqTotal)

    // 设置值
    reqTotal.Add(10)

    // 暴露指标
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe("localhost:9100", nil)
}

    image.png

    带有固定label指标的例子

    package main

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
    "net/http"
)

func main() {
    // 定义指标
    suceReqTotal := prometheus.NewCounter(prometheus.CounterOpts{
        Name:        "sucess_request_total",
        Help:        "请求成功的总数",
        ConstLabels: prometheus.Labels{"StatusCode": "200"},
    })
    // 注册指标
    prometheus.MustRegister(suceReqTotal)

    // 设置值
    suceReqTotal.Add(5675)

    // 暴露指标
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe("localhost:9100", nil)
}

    image.png

    带有非固定label指标的例子

    package main

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
    "net/http"
)

func main() {
    // 定义指标
    pathReqTotal := prometheus.NewCounterVec(prometheus.CounterOpts{
        Name: "path_request_total",
        Help: "path请求总数",
    }, []string{"path"})
    // 注册指标
    prometheus.MustRegister(pathReqTotal)

    // 设置值
    pathReqTotal.WithLabelValues("/token").Add(37)
    pathReqTotal.WithLabelValues("/auth").Add(23)
    pathReqTotal.WithLabelValues("/user").Add(90)
    pathReqTotal.WithLabelValues("/api").Add(67)
    // 暴露指标
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe("localhost:9100", nil)
}

    image.png

    3. Histogram指标类型

    不带label的基本例子

    package main

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
    "net/http"
)

func main() {
    // 定义指标
    reqDelay := prometheus.NewHistogram(prometheus.HistogramOpts{
        Name:    "request_delay",
        Help:    "请求延迟，单位秒",
        Buckets: prometheus.LinearBuckets(0, 3, 6), // 调用LinearBuckets生成区间，从0开始，宽度3，共6个Bucket
    })

    // 注册指标
    prometheus.MustRegister(reqDelay)

    // 设置值
    reqDelay.Observe(6)

    // 暴露指标
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe("localhost:9100", nil)
}

    image.png

    带固定label的例子

    package main

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
    "net/http"
)

func main() {
    // 定义指标
    reqDelay := prometheus.NewHistogram(prometheus.HistogramOpts{
        Name:        "request_delay",
        Help:        "请求延迟，单位秒",
        Buckets:     prometheus.LinearBuckets(0, 3, 6), // 调用LinearBuckets生成区间，从0开始，宽度3，共6个Bucket
        ConstLabels: prometheus.Labels{"path": "/api"},
    })

    // 注册指标
    prometheus.MustRegister(reqDelay)

    // 设置值
    reqDelay.Observe(6)
    // 暴露指标
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe("localhost:9100", nil)
}

    image.png

    带有非固定label的例子

    package main

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
    "net/http"
)

func main() {
    // 定义指标
    reqDelay := prometheus.NewHistogramVec(prometheus.HistogramOpts{
        Name:    "request_delay",
        Help:    "请求延迟，单位秒",
        Buckets: prometheus.LinearBuckets(0, 3, 6), // 调用LinearBuckets生成区间，从0开始，宽度3，共6个Bucket
    }, []string{"path"})

    // 注册指标
    prometheus.MustRegister(reqDelay)

    // 设置值
    reqDelay.WithLabelValues("/api").Observe(6)
    reqDelay.WithLabelValues("/user").Observe(3)
    reqDelay.WithLabelValues("/delete").Observe(2)
    reqDelay.WithLabelValues("/get_token").Observe(13)
    // 暴露指标
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe("localhost:9100", nil)
}

    image.png

    4.Summary指标类型

    不带label的例子

    package main

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
    "net/http"
)

func main() {
    // 定义指标
    reqDelay := prometheus.NewSummary(prometheus.SummaryOpts{
        Name:       "request_delay",
        Help:       "请求延迟",
        Objectives: map[float64]float64{0.5: 0.05, 0.90: 0.01, 0.99: 0.001}, // 百分比:精度
    })

    // 注册指标
    prometheus.MustRegister(reqDelay)

    // 设置值
    reqDelay.Observe(4)
    // 暴露指标
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe("localhost:9100", nil)
}

    image.png

    带有固定label的例子

    package main

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
    "net/http"
)

func main() {
    // 定义指标
    reqDelay := prometheus.NewSummary(prometheus.SummaryOpts{
        Name:        "request_delay",
        Help:        "请求延迟",
        Objectives:  map[float64]float64{0.5: 0.05, 0.90: 0.01, 0.99: 0.001}, // 百分比:精度
        ConstLabels: prometheus.Labels{"path": "/api"},
    })

    // 注册指标
    prometheus.MustRegister(reqDelay)

    // 设置值
    reqDelay.Observe(4)
    // 暴露指标
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe("localhost:9100", nil)
}

    image.png

    带有非固定label的例子

    package main

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
    "net/http"
)

func main() {
    // 定义指标
    reqDelay := prometheus.NewSummaryVec(prometheus.SummaryOpts{
        Name:       "request_delay",
        Help:       "请求延迟",
        Objectives: map[float64]float64{0.5: 0.05, 0.90: 0.01, 0.99: 0.001}, // 百分比:精度
    }, []string{"path"})

    // 注册指标
    prometheus.MustRegister(reqDelay)

    // 设置值
    reqDelay.WithLabelValues("/api").Observe(4)
    reqDelay.WithLabelValues("/token").Observe(2)
    reqDelay.WithLabelValues("/user").Observe(3)
    // 暴露指标
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe("localhost:9100", nil)
}

    image.png

    5. 值的修改

    5.1 基于事件的触发来修改值，比如每访问1次/api就增1

    基于事件的触发对指标的值进行修改，通常大多数是来自业务方面的指标需求，如自研的应用需要暴露相关指标给promethus进行监控、展示，那么指标采集的代码（指标定义、设置值）就要嵌入到自研应用代码里了。

    package main

import (
    "fmt"
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
    "net/http"
)

func main() {
    urlRequestTotal := prometheus.NewCounterVec(prometheus.CounterOpts{
        Name: "urlRequestTotal",
        Help: "PATH请求累计 单位 次",
    }, []string{"path"})

    http.HandleFunc("/api", func(w http.ResponseWriter, r *http.Request) {
        urlRequestTotal.WithLabelValues(r.URL.Path).Inc() // 使用Inc函数进行增1
        fmt.Fprintf(w, "Welcome to the api")
    })

    prometheus.MustRegister(urlRequestTotal)
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe("localhost:9100", nil)
}

    image.png

    基于时间周期的触发来修改值，比如下面的示例中，是每间隔1秒获取cpu负载指标

    基于时间周期的触发，可以是多少秒、分、时、日、月、周。

    package main

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
    "github.com/shirou/gopsutil/load"
    "net/http"
    "time"
)

func main() {
    cpuUsage := prometheus.NewGaugeVec(prometheus.GaugeOpts{
        Name: "CpuLoad",
        Help: "CPU负载",
    }, []string{"time"})

    // 开启一个子协程执行该匿名函数内的逻辑来给指标设置值，且每秒获取一次
    go func() {
        for range time.Tick(time.Second) {
            info, _ := load.Avg()
            cpuUsage.WithLabelValues("Load1").Set(float64(info.Load1))
            cpuUsage.WithLabelValues("Load5").Set(float64(info.Load5))
            cpuUsage.WithLabelValues("Load15").Set(float64(info.Load15))
        }
    }()

    prometheus.MustRegister(cpuUsage)
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe("localhost:9100", nil)
}

    image.png

    基于每访问一次获取指标的URI才修改值，比如每次访问/metrics才去修改某些指标的值

    下面的这个示例是，每访问一次/metrics就获取一次内存总容量

    package main

import (
    "fmt"
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"

    "github.com/shirou/gopsutil/mem"
    "net/http"
)

func main() {
    MemTotal := prometheus.NewGaugeFunc(prometheus.GaugeOpts{
        Name: "MemTotal",
        Help: "内存总容量 单位 GB",
    }, func() float64 {
        fmt.Println("call MemTotal ...")
        info, _ := mem.VirtualMemory()
        return float64(info.Total / 1024 / 1024 / 1024)
    })
    prometheus.MustRegister(MemTotal)
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe("localhost:9100", nil)
}

    image.png

    go
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