main.go

package main

import (
	"fmt"
	"net/http"
	"./newrelic"
)

func main() {
	agent, err := newrelic.NewAgent("license", "example", true)
	if err != nil {
		panic(err)
	}

	http.HandleFunc("/", agent.HandleFunc(func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprintln(w, "Hello world")
	}))
	http.ListenAndServe(":8000", nil)
}

newrelic.go

package newrelic

import (
	metrics "github.com/yvasiyarov/go-metrics"
	"github.com/yvasiyarov/gorelic"

type Agent struct {
	newrelicAgent *gorelic.Agent
}

func NewAgent(license string, appname string, verbose bool) (*Agent, error) {
	if license == "" {
		return nil, fmt.Errorf("Please specify a NewRelic license")
	}

	agent := &Agent{
		newrelicAgent: gorelic.NewAgent(),
	}

	agent.newrelicAgent.NewrelicLicense = license
	agent.newrelicAgent.NewrelicName = appname
	agent.newrelicAgent.HTTPTimer = metrics.NewTimer()
	agent.newrelicAgent.CollectHTTPStat = true
	agent.newrelicAgent.Verbose = verbose

	agent.newrelicAgent.Run()

	return agent, nil
}

func (a *Agent) HandleFunc(f func(w http.ResponseWriter, r *http.Request)) func(w http.ResponseWriter, r *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		startTime := time.Now()
		f(w, r)
		if a.newrelicAgent != nil {
			a.newrelicAgent.HTTPTimer.UpdateSince(startTime)
		}
	}
}