main_final.go

package main

import (
	"fmt"
	"github.com/newrelic/go-agent/v3/newrelic"
	"math/rand"
	"net/http"
	"os"
	"time"
)

var (
	app *newrelic.Application
	client = &http.Client{
		Transport: newrelic.NewRoundTripper(nil),
	}
)

func index (rw http.ResponseWriter, req *http.Request) {
	txn := newrelic.FromContext(req.Context())
	txn.AddAttribute("customerLevel", req.URL.Query().Get("customerLevel"))

	time.Sleep(15 * time.Millisecond)
	rw.Write([]byte("Hello World"))
}

func hoge(rw http.ResponseWriter, req *http.Request) {
	rw.Write([]byte("hoge"))

	txn := newrelic.FromContext(req.Context())
	txn.AddAttribute("customerLevel", req.URL.Query().Get("customerLevel"))

	func() {
		defer txn.StartSegment("segment1").End()
		time.Sleep(10 * time.Millisecond)
	}()

	s2 := txn.StartSegment("segment2")
	time.Sleep(15 * time.Millisecond)
	s2.End()
}

func external(rw http.ResponseWriter, r *http.Request) {
	rw.Write([]byte("外部呼び出し"))

	txn := newrelic.FromContext(r.Context())

	rand.Seed(time.Now().UnixNano())
	url := "http://example.com"
	if (rand.Intn(2) == 0) {
		url = "http://example.invalid"
	}
	req, err := http.NewRequest("GET", url, nil)
	if (err != nil) {
		txn.NoticeError(err)
		rw.Write([]byte(fmt.Sprintf("リクエスト作成失敗: %v", err)))
		return
	}

	//client := http.Client{}
	req = req.WithContext(r.Context())
	resp, err := client.Do(req)
	if (err != nil) {
		txn.NoticeError(err)
		rw.Write([]byte(fmt.Sprintf("リクエスト実行失敗: %v", err)))
		return
	}
	resp.Body.Close()
	rw.Write([]byte(fmt.Sprintf("呼び出しステータス: %v", resp.Status)))

}

type replacementMux struct {
	app *newrelic.Application
	*http.ServeMux
}

func (mux *replacementMux) HandleFunc(pattern string, fn func(http.ResponseWriter, *http.Request)) {
	mux.ServeMux.HandleFunc(newrelic.WrapHandleFunc(mux.app, pattern, fn))
}

func main() {
	//newrelic.NewApplication(func (cfg *newrelic.Config){
	//	cfg.AppName = "lab1"
	//}, func (cfg *newrelic.Config){
	//	cfg.License = os.Getenv("NEW_RELIC_LICENSE_KEY")
	//})
	//
	//newrelic.NewApplication(func (cfg *newrelic.Config){
	//	cfg.AppName = "lab1"
	//	cfg.License = os.Getenv("NEW_RELIC_LICENSE_KEY")
	//})

	var err error
	app, err = newrelic.NewApplication(
		newrelic.ConfigAppName("lab1"),
		newrelic.ConfigLicense(os.Getenv("NEW_RELIC_LICENSE_KEY")),
		newrelic.ConfigDebugLogger(os.Stdout),
		newrelic.ConfigFromEnvironment(),
		func (cfg *newrelic.Config){

		},
	)

	if (err != nil) {
		panic(err)
	}

	//http.HandleFunc("/", instrumentHandler("index", index))
	//http.HandleFunc("/hoge", instrumentHandler("hoge", hoge))

	//http.HandleFunc(newrelic.WrapHandleFunc(app, "/", index))
	//http.HandleFunc(newrelic.WrapHandleFunc(app, "/hoge", hoge))

	mux := replacementMux{ServeMux: http.NewServeMux(), app: app}
	//mux := http.NewServeMux()
	mux.HandleFunc("/", index)
	mux.HandleFunc("/hoge", hoge)
	mux.HandleFunc("/external", external)

	http.ListenAndServe(":8123", mux)
}

main_initial.go

package main

import (
	"fmt"
	"net/http"
	"time"
)

func index(rw http.ResponseWriter, req *http.Request) {
	time.Sleep(15 * time.Millisecond)
	rw.Write([]byte("Hello World"))
}

func hoge(rw http.ResponseWriter, req *http.Request) {
	func() {
		time.Sleep(100 * time.Millisecond)
	}()

	time.Sleep(150 * time.Millisecond)
	rw.Write([]byte("hoge"))
}

func external(rw http.ResponseWriter, r *http.Request) {
	rw.Write([]byte("外部呼び出し"))

	rand.Seed(time.Now().UnixNano())
	url := "http://example.com"
	if (rand.Intn(2) == 0) {
		url = "http://example.invalid"
	}
	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		rw.Write([]byte(fmt.Sprintf("リクエスト作成失敗: %v", err)))
		return
	}

	client := http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		rw.Write([]byte(fmt.Sprintf("リクエスト実行失敗: %v", err)))
		return
	}
	resp.Body.Close()
	rw.Write([]byte(fmt.Sprintf("呼び出しステータス: %v", resp.Status)))
}

func main() {
	mux := http.NewServeMux()
	mux.HandleFunc("/", index)
	mux.HandleFunc("/hoge", hoge)
	mux.HandleFunc("/external", external)

	http.ListenAndServe(":8123", mux)
}