Go AWS ELB Idle Timeout Test

healthcheck.go

package main

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

func main() {
	mux := http.NewServeMux()
	mux.HandleFunc("/healthcheck", func(w http.ResponseWriter, r *http.Request) {
		fmt.Printf("%v %v %v %v\n", time.Now().Format("2006-01-02 03:04:05 PM"), r.RemoteAddr, r.Method, r.URL)
		fmt.Fprintf(w, "ok")
	})
	http.ListenAndServe(":8081", mux)
}

main.go

package main

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

func main() {
	fmt.Println("Starting.")

	go func() {
		mux := http.NewServeMux()
		mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
			fmt.Printf("%v %v %v %v %v\n", time.Now().Format("2006-01-02 03:04:05 PM"), r.RemoteAddr, r.Method, r.URL, r.Header)
			wait := 0
			limit := 15
			for wait < limit {
				fmt.Println("Wait:", wait)
				time.Sleep(time.Second * 1)
				wait++
			}

			fmt.Fprintf(w, "Wait Done.")
		})
		mux.HandleFunc("/healthcheck", func(w http.ResponseWriter, r *http.Request) {
			fmt.Fprintf(w, "ok")
		})
		//http.ListenAndServe(":8080", mux)
		server := &http.Server{Addr: ":8080", Handler: mux}
		server.IdleTimeout = 2
		server.ListenAndServe()
	}()

	req, err := http.NewRequest("POST", "http://"+os.Getenv("ELBNAME")+":8080", nil)
	if err != nil {
		log.Println("Error creating POST request: ", err)
		return
	}
	req.Header.Set("Connection", "Keep-Alive")

	// setting long timeout for http client since scheduler MUST wait for responses
	client := http.Client{
		Timeout: time.Hour * 72,
		Transport: &http.Transport{
			Proxy: http.ProxyFromEnvironment,
			DialContext: (&net.Dialer{
				Timeout:   30 * time.Second,
				KeepAlive: 2 * time.Second,
				DualStack: true,
			}).DialContext,
			MaxIdleConns:          100,
			IdleConnTimeout:       3 * time.Second,
			TLSHandshakeTimeout:   10 * time.Second,
			ExpectContinueTimeout: 1 * time.Second,
			DisableKeepAlives:     false,
		},
	}
	res, err := client.Do(req)
	if err != nil {
		log.Println("Error sending POST request: ", err)
		return
	}
	defer res.Body.Close() //nolint
	fmt.Println("Returned:", res.StatusCode)

	fmt.Println("Done.")

	for {
	}
}