main.go

package main

import (
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"time"

	"github.com/gin-gonic/gin"
	"go.uber.org/zap"
	gintrace "gopkg.in/DataDog/dd-trace-go.v1/contrib/gin-gonic/gin"
	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
)

var logger, _ = zap.NewProduction()

func getEnv(key string, def string) string {
	value := os.Getenv(key)
	if value != "" {
		return value
	}
	return def
}

func initDatadog(r *gin.Engine) {
	host := os.Getenv("DATADOG_TRACE_AGENT_HOSTNAME")
	if host == "" {
		return
	}

	env := getEnv("DATADOG_ENV", "development")
	addr := fmt.Sprintf("%s:%d", host, 8126)
	service := getEnv("DATADOG_SERVICE_NAME", "gin-test")
	log.Printf("Set datadog addr=%s, tag env=%s, service=%s\n", addr, env, service)
	tracer.Start(
		tracer.WithAgentAddr(addr),
		tracer.WithGlobalTag("env", env),
	)
	r.Use(gintrace.Middleware(service))
}

func accessLoop(url string) {
	ticker := time.NewTicker(10 * time.Second)
	defer ticker.Stop()
	for range ticker.C {
		res, err := http.Get(url)
		if err != nil {
			log.Println(err)
			continue
		}
		io.Copy(ioutil.Discard, res.Body)
		res.Body.Close()
	}

}

func main() {

	r := gin.Default()
	initDatadog(r)

	r.GET("/yahoo", func(c *gin.Context) {
	})
	r.GET("/google", func(c *gin.Context) {
	})

	r.Run(":8080")
}