golang程序对接prometheus过程

go get github.com/prometheus/client_golang/prometheus
go get github.com/prometheus/client_golang/prometheus/promhttp

var (
    requestsTotal = prometheus.NewCounter(
        prometheus.CounterOpts{
            Name: "http_requests_total",
            Help: "Total number of HTTP requests",
        },
    )
)

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

http.Handle("/metrics", promhttp.Handler())
http.ListenAndServe(":8080", nil)

func handler(w http.ResponseWriter, r *http.Request) {
    requestsTotal.Inc()
    w.Write([]byte("Hello World"))
}

requestsByStatus := prometheus.NewCounterVec(
    prometheus.CounterOpts{
        Name: "http_requests_by_status",
        Help: "Requests grouped by status code",
    },
    []string{"code"},
)

reg := prometheus.NewRegistry()
reg.MustRegister(customMetric)
handler := promhttp.HandlerFor(reg, promhttp.HandlerOpts{})

package main

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

var (
    requestsTotal = prometheus.NewCounter(
        prometheus.CounterOpts{
            Name: "myapp_requests_total",
            Help: "Total requests served",
        })
)

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

func main() {
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        requestsTotal.Inc()
        w.Write([]byte("OK"))
    })
    
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe(":8080", nil)
}