httpserver2.go

package main

import (
	"fmt"
	"gocamp/metrics"
	"io"
	"log"
	"math/rand"
	"net"
	"net/http"
	"net/http/pprof"
	"os"
	"strings"
	"time"

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

func index(w http.ResponseWriter, r *http.Request) {
	// w.Write([]byte("<h1>Welcome to Cloud Native</h1>"))
	// 03.设置version   os.Setenv("VERSION", "v0.0.1")
	version := os.Getenv("VERSION")
	w.Header().Set("VERSION", version)
	fmt.Printf("os version: %s \n", version)
	// 02.将requst中的header 设置到 reponse中
	for k, v := range r.Header {
		for _, vv := range v {
			{
				fmt.Printf("Header key: %s, Header value: %s \n", k, v)
				w.Header().Set(k, vv)
			}
			io.WriteString(w, fmt.Sprintf("%s=%s\n", k, v))
		}
		// 04.记录日志并输出
		clientip := getCurrentIP(r)
		//fmt.Println(r.RemoteAddr)
		log.Printf("Success! Response code: %d", 200)
		log.Printf("Success! clientip: %s", clientip)
	}
}

// 05.健康检查的路由

func healthz(w http.ResponseWriter, r *http.Request) {

	fmt.Fprintf(w, "200")
}
func getCurrentIP(r *http.Request) string {
	// 这里也可以通过X-Forwarded-For请求头的第一个值作为用户的ip
	// 但是要注意的是这两个请求头代表的ip都有可能是伪造的
	ip := r.Header.Get("X-Real-IP")
	if ip == "" {
		// 当请求头不存在即不存在代理时直接获取ip
		ip = strings.Split(r.RemoteAddr, ":")[0]
	}
	return ip
}

// ClientIP 尽最大努力实现获取客户端 IP 的算法。
// 解析 X-Real-IP 和 X-Forwarded-For 以便于反向代理（nginx 或 haproxy）可以正常工作。
func ClientIP(r *http.Request) string {
	xForwardedFor := r.Header.Get("X-Forwarded-For")
	ip := strings.TrimSpace(strings.Split(xForwardedFor, ",")[0])
	if ip != "" {
		return ip
	}
	ip = strings.TrimSpace(r.Header.Get("X-Real-Ip"))
	if ip != "" {
		return ip
	}
	if ip, _, err := net.SplitHostPort(strings.TrimSpace(r.RemoteAddr)); err == nil {
		return ip
	}
	return ""
}

func images(w http.ResponseWriter, r *http.Request) {
	timer := metrics.NewTimer()
	defer timer.ObserveTotal()
	randInt := rand.Intn(2000)
	time.Sleep(time.Millisecond * time.Duration(randInt))
	w.Write([]byte(fmt.Sprintf("<h1>%d<h1>", randInt)))
}

func main() {
	metrics.Register()
	mux := http.NewServeMux()
	// 06. debug   mux.HandleFunc("/debug/pprof/", pprof.Index)
	mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
	mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
	mux.HandleFunc("/debug/pprof/trace", pprof.Trace)
	mux.HandleFunc("/", index)
	mux.HandleFunc("/images", images)
	mux.HandleFunc("/healthz", healthz)
	mux.Handle("/metrics", promhttp.Handler())
	if err := http.ListenAndServe(":8080", mux); err != nil {
		log.Fatalf("start http server failed, error: %s\n", err.Error())

	}
}