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动手写prometheus的exporter-01-Gauge（仪表盘）

2022-08-08 23:01:00 【开发运维玄德公】

文章目录

1. 不带lab的Gauge
2. 带lab的Gauge

特点：数据可增减（反应当前状态）。

1. 不带lab的Gauge

1.1 定义指标

语法

实例化

func NewGauge(opts GaugeOpts) Gauge

GaugeOpts

type GaugeOpts Opts

结构体Opts

type Opts struct {
    
    Namespace   string
    Subsystem   string
    Name        string
    Help        string
    ConstLabels Labels
}

完整示例

写一段简单的exporter如下：

package main

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

//自定义端口
var addr = flag.String("listen-address", ":1840", "The address to listen on for HTTP requests")

var (
	numOfBuns = prometheus.NewGauge(prometheus.GaugeOpts{
    
		Namespace: "xi_shu",
		Subsystem: "jing_zhou_team",
		Name:      "guanyu_eaten_num",
		Help:      "Number of steamed buns eaten by Guan Yu",
	})
)

func init() {
    
	prometheus.MustRegister(numOfBuns)
}

func main() {
    
	flag.Parse()
	http.Handle("/metrics", promhttp.Handler())
	log.Fatal(http.ListenAndServe(*addr, nil))
}

结果如下
我们访问http://127.0.0.1:1840/metrics页面，可以找到如下一段

# HELP xi_shu_jing_zhou_team_guanyu_eaten_num Number of steamed buns eaten by Guan Yu
# TYPE xi_shu_jing_zhou_team_guanyu_eaten_num gauge
xi_shu_jing_zhou_team_guanyu_eaten_num 0

如上可知，我们的指标是用Opts结构体的实例化拼接出来的。

1.2 给指标取值

语法

add() 增加n

func (Gauge) Add(float64)

sub() 减去n

func (Gauge) Sub(float64)

Inc() 增加1

func (Gauge) Inc()

dec() 减少1

func (Gauge) Dec()

set() 重新设置

func (Gauge) Set(float64)

设置值为当前时间时间戳

func (Gauge) SetToCurrentTime()

完整示例

代码

package main

import (
	"flag"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promhttp"
	"log"
	"net/http"
	"time"
)
var addr = flag.String("listen-address", ":1840", "The address to listen on for HTTP requests")

var (
	numOfBuns = prometheus.NewGauge(prometheus.GaugeOpts{
    
		Namespace: "xi_shu",
		Subsystem: "jing_zhou_team",
		Name:      "guanyu_eaten_num",
		Help:      "Number of steamed buns eaten by Guan Yu",
	})
)

func init() {
    
	prometheus.MustRegister(numOfBuns)
}

func main() {
    
	flag.Parse()
	go func() {
    
		for true {
    
			numOfBuns.Add(2)
			time.Sleep(time.Second)
		}
	}()
	http.Handle("/metrics", promhttp.Handler())
	log.Fatal(http.ListenAndServe(*addr, nil))
}

结果

我们不断刷新可见，每秒钟关羽吃的馒头+2

# HELP xi_shu_jing_zhou_team_guanyu_eaten_num Number of steamed buns eaten by Guan Yu
# TYPE xi_shu_jing_zhou_team_guanyu_eaten_num gauge
xi_shu_jing_zhou_team_guanyu_eaten_num 24

2. 带lab的Gauge

2.1 定义指标

语法

实例化

func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec

GaugeOpts 见上例

完整示例

package main

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

//自定义端口
var addr = flag.String("listen-address", ":1840", "The address to listen on for HTTP requests")

var (
	numOfBuns = prometheus.NewGaugeVec(prometheus.GaugeOpts{
    
		Namespace: "xi_shu",
		Subsystem: "jing_zhou_team",
		Name:      "eaten_num",
		Help:      "Number of steamed buns eaten by Guan Yu",
	},[]string{
    "name","age"})
)

func init() {
    
	prometheus.MustRegister(numOfBuns)
}

func main() {
    
	flag.Parse()
	http.Handle("/metrics", promhttp.Handler())
	log.Fatal(http.ListenAndServe(*addr, nil))
}

结果显示
有lab的Counter没有赋值是看不见的（而上例可知，没有tag的Counter模式值是0。）

2.2 取值

语法

添加lab
实例化之后，需要先给实例打上lab，因为不同的lab会单独作为一个数据显示。

func (v *GaugeVec) WithLabelValues(lvs ...string) Gauge

取值

见前文，同“不带lab的Gauge”

完整示例

代码如下

package main

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

//自定义端口
var addr = flag.String("listen-address", ":1840", "The address to listen on for HTTP requests")

var (
	numOfBuns = prometheus.NewGaugeVec(prometheus.GaugeOpts{
    
		Namespace: "xi_shu",
		Subsystem: "jing_zhou_team",
		Name:      "eaten_num",
		Help:      "Number of steamed buns eaten by Guan Yu",
	},[]string{
    "name","age"})
)

func init() {
    
	prometheus.MustRegister(numOfBuns)
}

func main() {
    
	flag.Parse()
	go func() {
    
		for true {
    
			numOfBuns.WithLabelValues("guan_yu","25").Add(2)
			time.Sleep(time.Second)
		}
	}()
	go func() {
    
		for true {
    
			numOfBuns.WithLabelValues("zhang_fei","22").Add(3)
			time.Sleep(time.Second)
		}
	}()
	http.Handle("/metrics", promhttp.Handler())
	log.Fatal(http.ListenAndServe(*addr, nil))
}

结果

# HELP xi_shu_jing_zhou_team_eaten_num Number of steamed buns eaten by Guan Yu
# TYPE xi_shu_jing_zhou_team_eaten_num gauge
xi_shu_jing_zhou_team_eaten_num{
    age="22",name="zhang_fei"} 21
xi_shu_jing_zhou_team_eaten_num{
    age="25",name="guan_yu"} 14