一个简单的exporter示例文件

package main

import (
	"fmt"
	"log"
	"net/http"

	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promhttp"
)

// 定义一个指标，用于记录请求总数
var requestTotal = prometheus.NewCounter(
	prometheus.CounterOpts{
		Name: "request_total",
		Help: "Total number of requests",
	},
)

// 初始化函数，注册指标
func init() {
	prometheus.MustRegister(requestTotal)
}

// 处理请求的函数，每次请求都会增加指标的值
func handler(w http.ResponseWriter, r *http.Request) {
	requestTotal.Inc()
	fmt.Fprintf(w, "Hello, world!")
}

func main() {
	// 设置路由，使用promhttp包提供的Handler函数
	http.HandleFunc("/", handler)
	http.Handle("/metrics", promhttp.Handler())

	// 监听8080端口
	addr := "0.0.0.0:8080"
	fmt.Printf("Listening on %s\n", addr)
	log.Fatal(http.ListenAndServe(addr, nil))
}